integrated science grade 8 week: one content
TRANSCRIPT
Integrated Science Grade 8
Week: One
Lesson: One
Topic: Energy
Content
What is Energy?
The simplest definition of energy is "the ability to do work". Energy is how things change and
move. It's everywhere around us and takes all sorts of forms. It takes energy to cook food, to drive
to school, and to jump in the air.
Types of Energy
There are two types of energy:
Kinetic (or energy in motion)
Potential (or stored energy)
Kinetic Energy
Any object in motion is using kinetic energy. For example, when a cricketer throws a cricket ball, the
“moving” ball has kinetic energy. Moving water and wind are also examples of kinetic energy. Electricity is
kinetic energy because even though you can't see it happen, electricity involves electrons moving along a
conductor.
Potential Energy
Potential energy is stored energy that can be converted to kinetic energy. A gallon of gasoline or a barrel of
oil contains stored energy that can be released when it is burnt. A lake in the mountains contain "stored"
energy because, if it were released, it would do a lot of work on objects caught in its path. When we talk
about oil, coal, wood, or gas, we are talking about "stored" energy.
Kinetic energy and potential energy can change forms. For example, a car moving up a hill has
kinetic energy. When the car reaches the top of the hill and is about to go down the hill, that is
the potential energy. When the car moves forward down the hill it is then again kinetic energy.
Forms of Energy
Examples of Kinetic and Potential Energy
Energy Conversion
An object's energy can be converted from one form to another.
Energy transfer is the movement of energy from one location to another. For example, when
electricity moves from a wall plug, through a charger, to a battery.
Energy transformation or conversion is when energy changes from one form to
another – like in a hydroelectric dam that transforms the kinetic energy of water into electrical
energy.
Examples:
Gasoline (chemical) is put into our cars, and with the help of electrical energy from a battery,
provides mechanical (kinetic) energy.
Purchased electricity is fed into our TVs and is converted to light and sound.
Similarly, purchased electricity goes into an electric bulb and is converted to visible light and
heat energy.
Law of Conservation
This law states that energy cannot be created or destroyed, but only changed from one form into
another or transferred from one object to another.
Examples of Energy Conversions
References
Kid's Korner (apogee.net)
Types of energy (article) | Khan Academy
Energy Conversion - Knowledge Bank - Solar Schools
Energy Conversion | EGEE 102: Energy Conservation and Environmental Protection (psu.edu)
Energy and Its Types - JustScience
Week: One
Lesson: One
Worksheet: Energy
Part A: Write them in the empty spaces and find these hidden words in the puzzle!
1. ________ gives you energy. Some foods give more _________ than others.
2. Energy is all ________ you. It is the ________ that allows things to move and happen.
3. The ____ gives them energy to grow. We eat them and they give us energy.
4. These ________ can harness the energy of wind to make electricity.
5. Scientists are working hard to find other kinds of energies. These are called alternative
________.
6. When we use too much of these kinds of energy, the temperature of our planet rises. This is
called the ____________ effect.
7. Energy can be ________ from one form to another. ________ can be burned to make heat
or electricity.
8. Coal, oil and gas are stored in the ________. Coal and oil come from the remains of
_________ animals.
R A I N E D E S U O H N E E R G
D E F O O D D U S L O R D F S R
E A R O U N D F A W R T E U U X
G O N G E D E L A V Y G R E N E
N I A S P T G O B A C O A L O C
A G R O U N D W E D A S E S K R
H E R T D E Z I L I S S O F L O
C V W I N D M I L L S A W E P F
Part B: Complete the cross work by using the clues below.
1 2
3
4 5
6
7 8
9 10
11
12
13 14
15 16
17
18
19 20
Across
1. law which states energy cannot be created or
destroyed only transferred
4. a person who designs safe energy systems
12. energy that can be used more than once
Down
2. The ability to do work
3. visible light energy
5. (chemistry) of, or relating to a chemical
reaction brought about by electricity
13. for example, logs burning in a fireplace
15. a form of solar energy, describes the process
by which wind is used to generate electricity.
17. radiant energy emitted by the sun
18. a form of energy that can be reflected or
emitted from objects through electrical or
magnetic waves traveling through space.
19. stored energy
20. kinetic plus potential energy
6. energy derived from the movement of water.
7. a natural fuel such as coal or gas, formed in
the geological past from the remains of living
organisms
8. the energy released during nuclear fission or
fusion, especially when used to generate
electricity
9. energy that happens when two or more
molecules have a chemical reaction
10. energy found in two electrically charged
particles
11. energy of motion
14. energy you can hear
16. energy which gives heat
Part C: Using the pictures below, create a scrap book and provide written explanation for the
transformation of energy in each case.
1. Flashlight 3. Solar Panel
2. Speaking on the telephone 4. Camp fire
Week: One
Lesson: Two
Topic: Machines
Content
What is a machine?
A machine is a device that uses a mechanical system to accomplish a task. A mechanical system
is a series of interrelated, moving parts that work together to accomplish a simple task.
The word “machine” comes from the Greek word meaning “to help make things easier.”
Machines are therefore devices that make our work easier, they change the direction of a force
and do work efficiently. Machines can be classified as being simple or complex.
Types of Machines
Simple machines are devices that can be used to multiply a force that we apply (effort) at a more
convenient point (distance). Simple machines are devices with no, or very few, moving parts that
make work easier. Levers, wheel and axles, pulleys, wedges, inclined planes, and screws are some
examples of simple machines.
source: (Lucas,2018).
Features of a simple machine
- They do not use electricity
- They have one or fewer moving parts
- They give us a mechanical advantage
- Even though they make work easier for us, they still need input (force or effort) from a
person.
- They make tough jobs easier by changing the force, direction, or speed of a movement.
Complex Machines
Complex machines can be created by combining one or more simple machines and a power source.
These machines can be as small as a mechanical watch or as large as a construction crane. Some
complex machines can also be classified as compound machines. Compound machines are made
up of two or more simple machines used together to accomplish a task. Examples of complex and
compound machines are bicycles, wheelbarrows, cranes, car jacks, lawnmowers. It is important to
note that some of the devices listed use a power source, hence those are complex machines. The
machines that use no power source are compound machines.
source: (Lucas,2018).
Usefulness of Machines
A machine makes work easier to perform. They do not decrease the amount of work you do. Work
is defined as a force acting on an object in the direction of the motion. Example: When you exert
a force on an object that force causes the object to move some distance in a particular direction.
Machines are useful because they provide a mechanical advantage by decreasing the effort you
apply but the distance is increased. Therefore, machines make work easier to perform by
accomplishing one or more of the following functions:
- transferring a force from one place to another,
- changing the direction of a force,
- increasing the magnitude of a force, or
- increasing the distance or speed of a force.
Reference
https://www.chathamnj.org/cms/lib/NJ01000518/Centricity/Domain/688/Simple%20and%20Co
mplex%20Machines.pdf
https://www.livescience.com/49106-simple-
machines.html#:~:text=The%20most%20notable%20of%20these,combinations%20of%20the%2
0first%20three.
Machine Class 8 Science | Notes | Khullakitab
Unit 3 - 8th Grade Physical Science (weebly.com)
Week: One
Lesson: Two
Topic: Machines
1. Which of the following is true about machines?
A. machines do all the work, hence people do not have to
B. machines help to make the work easier and faster
C. machines do not allow for the conservation of energy
D. humans can do more difficult jobs than machines
2. All of the following are examples of simple machines EXCEPT
A. a pencil sharpener
B. a screw
C. a wheelchair ramp
D. a sea saw
3. There are ---------------- types of simple machines
A. 2
B. 4
C. 6
D. 8
4. The types of simple machines are
A. first-class lever, second class lever, wedge, screw
B. lever, ax, pulley, wheel, hammer, screw,
C. lever, pulley, inclined plane, screw, wheel and axle, wedge
D. block and tackle, levers, screw, pulley, inclined plane, wheel and axle
The diagram below represents a complex machine
5. How many types of simple machines make up the scissors
A. 2
B. 3
C. 4
D. 5
6. The types of simple machines that make up the scissors are
A. wedge and lever
B. wedge, lever and wheel and axle
C. lever and wheel and axle
D. an inclined plane, lever, wheel and axle, and wedge
7. Which of the following is not a complex machine?
A. bicycle
B. sharpener
C. nutcracker
D. a sea saw
8. Which complex machine does not consist of a wheel and axle
A. wheelbarrow
B. sand truck
C. nutcracker
D. bicycle
9. A simple machine that has a chain wrapped around a wheel is called
A. pulley
B. wedge
C. inclined plane
D. lever
10. The picture shown below can make work easier by doing all of the following EXCEPT
A. transfer a force from one place to another,
B. change the direction of a force,
C. increase the magnitude of a force
D. decrease the magnitude of a force
11. Simple machines in a bicycle include
A. wheels and axles.
B. pulleys.
C. levers.
D. all of the above
12. Which of the following is a compound machine?
A. wheel and axle
B. scissors
C. pulley
D. lever
13. The mechanical advantage of a compound machine equals the
A. sum of the mechanical advantages of all its simple machines.
B. product of the mechanical advantages of all its simple machines.
C. highest mechanical advantage of all its simple machines.
D. average mechanical advantage of all of its simple machines.
14. The way friction is reduced in a compound machine such as a car is with
A. fans.
B. heaters.
C. lubricants.
D. none of the above
Determine if the following statements are true or false.
_____ 1. Some compound machines consist of thousands of simple machines.
_____ 2. Compound machines have more moving parts than simple machines.
_____ 3. The fewer simple machines a compound machine contains, the greater its mechanical
advantage.
_____ 4. Compound machines have more friction to overcome than do simple machines.
_____ 5. Machines decrease the amount of work we have to do even as it makes work easier.
Essay Questions
1. Why do compound machines tend to have lower efficiency than simple machines?
2. Which will have a greater mechanical advantage: a compound machine that consists of
200 simple machines or a compound machine that consists of 2 simple machines?
Explain your answer.
Week: One
Lesson: Three
Topic: Simple Machines - Levers
Content
A lever is a simple machine made of a rigid beam and a fulcrum. The effort (input force) and
load (output force) are applied to either end of the beam. The fulcrum is the point on which the
beam pivots. When an effort is applied to one end of the lever, a load is applied at the other end
of the lever. This will move a mass upward. Levers rely on a twisting force (torque) for their
operation. Torque is the amount of force required to cause an object to rotate around its axis (or
pivot point). There are three classes of levers – first, second and third-class levers.
Classes of Levers
First-class (also called first-order) levers have the applied force on one side of the fulcrum and
the load or resistance on the other side of the fulcrum. Moving the fulcrum closer to the load end
increases the effectiveness of the force from the effort end. These types of levers may be the most
easily recognized levers. Examples are seesaws and a pair of scissors.
source: (Blaettler, 2019)
Scissors and shears are first-class levers,
even though the fulcrum is slightly off-
centered. The centralized fulcrum still
serves as the pivot point that allows you
to raise and lower the dual bars at one
end with the handles on the other end.
Scissors are an example of a lever that
uses force to cut or separate materials.
Second-Class Levers
Second-class (or second-order) levers have the applied force on one end of the lever and the
fulcrum on the other side of the lever. The load or resistance lies between the fulcrum and the
applied force.
source: (Blaettler, 2019)
A bottle opener is a second-class lever because the pivot point
is at one end of the opener and the load is in the middle. In
this case, the load is the bottle itself, or specifically the
secured bottle cap on the bottle, and the handle provides a
way to lift and remove the cap from its tightly secured
position.
Third-Class Levers
Third-class (or third-order) levers have the load at one end of the lever and the fulcrum at the other
end of the lever. The applied force occurs between the load and the fulcrum.
source: (Blaettler, 2019)
Tweezers and tongs are third-class levers because the fulcrum is at
one end and the load is at the other. You must use human effort in
the center of the lever to pinch the tweezers or tongs to grasp and
lift or remove materials.
Reference
https://sciencing.com/ten-different-types-levers-7285923.html
https://sciencing.com/levers-used-everyday-life-8435160.html
Levers have a lot of Class | City Technology
Week: One
Lesson: Three
Worksheet: Machines - Levers
1. On a lever, the fulcrum is................
A. the point where the force applied to the lever
B. the spot where the lever is weakest
C. the point the lever balances or pivots on
D. the object being lifted or moved
2. On a lever, the load is
A. the object being lifted or moved
B. the centre of gravity
C. the point where the force is applied to the lever
D. the point the lever balances or pivots on
3. On a lever, the effort is
A. the spot where the load is placed
B. the object being lifted or moved
C. the point where the force applied to the lever
D. the point the lever balances or pivots on
4. Which is an example of someone using a simple machine to do work?
A. a boy runs across a football field
B. a banker counts money
C. a mother pushes a stroller up a ramp into a building
D. a girl eats a sandwich
5. The picture below shows an example of which class of lever
A. 1st class lever
B. 2nd class lever
C. 3rd class lever
D. none of the above
6. Which of the following statements best describes the human arm
A. the effort is between the fulcrum and the load
B. the load is between the fulcrum and the effort
C. the load is at one end and the pivot is at the other end
D. the effort is in the muscle, the load is in the wrist and the pivot is the joint
7. Which of the following is an example of a second class lever?
A. a nutcracker
B. a wheelbarrow
C. a sea saw
D. a pair of pliers
8. In a second class lever the
A. fulcrum is placed anywhere
B. the effort is between the fulcrum and the load
C. the fulcrum is between the effort and the load
D. load is between the effort and the fulcrum
Study the diagram below and then answer questions 9 and 10.
9. The letter W represents the
A. load
B. effort
C. fulcrum
D. pivot
10. The P represents the
A. load
B. effort
C. fulcrum
D. pivot
Complete the Crossword using the clues given,
DOWN
Week: Two
Lesson: One
Topic: Simple Machines – Inclined
Plane and Wheel & Axle
Content
An inclined plane, also known as a ramp, is a
flat supporting surface tilted at an angle, with
one end higher than the other, it is used as an
aid for raising or lowering a load.
How does an inclined plane work?
An inclined plane allows you to exert your input force over a longer distance, making the input
force needed less than the output force. Example: When a ramp is used to move an object, it
moves the object from a lower level to a higher level using less force. Inclined planes, therefore,
have a mechanical advantage that is greater than one since less force is put into moving an object
up a slope than if it was lifted straight up.
The mechanical advantage of an inclined plane is the input force over the output force. To
determine the ideal mechanical advantage of an inclined plane, the length of the incline is
divided by its height.
MA = length/distance
Example: Mr. Mike is loading a truck with a ramp that is three meters (3m) long and one meter
(1m) high. What is the mechanical advantage of the ramp?
MA = 3m/1m
MA = 3
Note that mechanical advantage has no units.
Characteristics of an inclined plane
- An inclined plane must have a mechanical advantage
- An inclined plane must have a slope
- An inclined plane must have a length
- An inclined plane must have a height
Examples of Inclined planes
- Roller coasters
- Bathtubs
- Boat propellers
- Parking ramps
- Car ramps
- Ladder
- Stairs
- Dump Truck
Advantages and Disadvantages of using an inclined plane
Advantages Disadvantages
- the inclined plane does not move
therefore it is very stable.
- the inclined plane can be at any angle
for maximum flexibility.
- some amount of energy will still be
required to move the object that has to
be elevated since the inclined plane
does not move.
Wheel and Axle
The wheel and axle is a type of simple machine used to make tasks easier. The wheel and axle
consist of a round disk, known as a wheel, with a rod through the centre of it, known as the axle.
source:(eSchoolToday, 2008)
Uses of Wheel and Axle
Wheel and axle are used for lifting heavy objects, moving people quickly, and moving parts of a
complex machine. There are two basic types of wheel and axle simple machines.
1. A machine where the force is applied to the axle
2. A machine where the force is applied
to the wheel
Examples of Force Applied to Axle
Applying a large force to the axle makes the
wheel go faster. Everyday examples of this
type of wheel and axle include:
- Bicycle
- Car tires
- Ferris wheel
- Electric fan
- Analog clock
- Winch
A Ferris wheel is an example of force being applied to the axle. When the axle turns it results
in the giant wheel turning. The wheel is much larger than the axle and covers more distance
and area. A ceiling fan works the same way.
Examples of Force Applied to Wheel
When you apply a small force to the wheel,
it travels a longer distance and creates a
stronger force on the axle. Everyday
examples of this type of wheel and axle
include:
- Screwdriver
- Drill
- Windmill
- Water wheel
- Doorknob
- Pizza cutter
- Skateboard
An example of a force being applied to the wheel is when a doorknob is turned. The wheel
(doorknob) is turned and the locking mechanism connected to the shaft turns and the door can
then be opened.
References
https://energyeducation.ca/encyclopedia/Inclined_plane
https://pulleys.weebly.com/inclined-plane.html
https://energyeducation.ca/encyclopedia/Mechanical_advantage
https://energyeducation.ca/encyclopedia/Wheel_and_axle#:~:text=The%20wheel%20and%20axl
e%20consists,is%20closely%20related%20to%20gears.
Grade 8 Science (Shafer) Simple Machines Notes: Inclined Plane and Lever You'll Remember |
Quizlet
Wheel and Axle Examples (softschools.com)
Week: Two
Lesson: One
Worksheet: Simple Machines – Inclined Plane and Wheel & Axle
1. A stair is an example of
A. inclined plane
B. screw
C. wheel and axle
D. pulley
2. A (n) ………………….. is also know as a ramp
A. wheel and axle
B. pulley
C. inclined plane
D. 3rd class lever
3. Which of the following is NOT a characteristic of the picture shown below.
A. it must have a slope
B. it must have a length
C. it must have a height
D. it must have a width
4. All of the following are examples of force applied to the part labeled A Except
A. drill
B. door knob
C. pizza cutter
D. bicycle
5. An example of where the force is applied to the part labeled B is
A. Ferris wheel
B. drill
C. door knob
D. pizza cutter
6. Which of the following is not an example of an inclined plane
A. bath tub
B. ramp
C. latter
D. water wheel
7. Which of the following has only simple machines
A. television, computer, lever
B. screw, car, tires
C. lawn mower, leaf dryer, edger
D. lever, screw, wheel
8. A wheel and axle is an example of
A. wheel barrow
B. complex machine
C. compound machine
D. simple machine
9. Which simple machine is closely related to gears
A. levers
B. wheel and axle
C. inclined plane
D. screw
10. Which of the following are variations of an inclined plane
A. wedge and screw
B. wedge and wheel and axle
C. pulley and screw
D. wedge and pulley
11. Elizabeth pushes a box 12 meters up a ramp to load a truck that is 2 meters off the
ground. What is the ideal mechanical advantage of the ramp?
A. 0.17
B. 6
C. 2
D. 0
12. How does a ramp make work easier?
A. By giving you more output work that you input.
B. By giving you more output force than you input.
C. By giving you less output work than you input.
D. By changing the direction of the force.
13. A 5-meter ramp lifts objects to a height of 0.75 meters. What is the mechanical advantage
of the ramp?
A. 0.15
B. 6.7
C. 3.75
D. 0.75
14. Joey’s little brother makes a ramp to push hos toy dump truck up to his sandbox. If he
uses 5N of force to push the 12N truck up the ramp, what is the mechanical advantage of
his ramp?
A. 6.0
B. 0.42
C. 2.4
D. 23.5
15. A ramp with a mechanical advantage of 13 lifts objects to a height of 11 meters. How
long is the ramp?
A. 0.84m
B. 1.2m
C. 143m
D. 14.3m
Week: Two
Lesson: Two
Topic: Simple Machines – Pulley
The Pulley
A pulley is simply a wheel with a groove and a rope in the groove. The groove is important because
it helps to keep the rope in place. A pulley is used to lift or lower heavy objects. With a pulley, the
item to be lifted is tied to one end of the rope. A force is applied to the other end by pulling the
rope downwards. The downward force turns the wheel with the rope and pulls the load upward at
the other end.
source: (eSchoolToday, 2008)
Types of Pulleys
There are three main types of pulleys. However, each pulley system depends on how the wheel
and ropes are combined. Now let us examine some of the types of pulleys listed above.
1. Fixed Pulley
It is the simplest form of pulleys. Simple pulleys have
their axles fixed in place and cannot be moved. The rope
moves in the groove of the pulley, but the wheel is fixed
to one spot. The wheel on your school flag pole is a
good example.
2. Movable Pulley
In a movable pulley, a load is attached to the
pulley and both of them can move from
place to place. In this type, one end of the
rope is attached to a fixed point that does not
move. With a movable pulley, you need less
effort to lift a load.
3. Compound Pulley
This is also called a combined pulley. It is a combination of pulleys designed to make the
effortless than half of the weight of the load. This kind is common at construction sites
where cranes lift very heavy steel and concrete objects. One good example of a
compound pulley is a Block and Tackle.
A block and tackle is a combination of pulleys and ropes used for lifting heavy loads. It can
reduce the effort required to move a heavy object. It has several movable and fixed pulleys
arranged parallel to each other in such a way that fixed ones are aligned and the movable
ones are also aligned.
source: (eSchoolToday, 2008)
References
How to Rig a Block & Tackle | Hunker
Types of Pulleys and How do They Work? - Pulleys (weebly.com)
How do pulleys work? - Explain that Stuff
Pulley Examples: Common Ways They're Used (yourdictionary.com)
Week: Two
Lesson: Two
Worksheet: Simple Machines – Pulleys
1. A pulley is
a. a bar used to lift heavy objects.
b. a wheel with a groove for a rope.
c. made of two inclined planes.
d. a lever with an arm and a fulcrum.
2. Which is another term for block and tackle?
a. fixed pulley
b. movable pulley
c. compound pulley
3. Which is an example of a movable pulley?
a. b.
4. Name the type of pulley shown in the diagram below.
a. fixed pulley
b. movable pulley
c. block and tackle
5. Name the type of pulley shown in the diagram below.
a. fixed pulley
b. movable pulley
c. block and tackle
6. It has one pulley and part of the load is carried by the pulley making the work easier.
a. Two Pulleys Together (block and tackle)
b. Single Fixed Pulley
c. Single Movable Pulley
7. Two types of pulleys are
a. wheel and rope.
b. fixed and movable.
c. compound and block and tackle.
8. Which of the following pulleys or systems provides a mechanical advantage? Choose the
best answer.
a. Single Fixed Pulley, Single Movable Pulley, Block and Tackle
b. Single Movable Pulley, Block and Tackle
c. Single Fixed Pulley, Single Movable Pulley
d. Single Fixed Pulley, Block and Tackle
e. None of the above
9. The tools shown are a combination of which two simple machines?
a. lever and screw
b. wedge and lever
c. screw and pulley
d. pulley and wedge
A pulley and first class lever are shown. Study the diagrams then answer question 10.
Pulley
First Class Lever
10. Which statement best describes the relationship between the pulley and first class lever?
a. The pulley is similar to the first class lever because it has a fulcrum between the load and
effort force.
b. The pulley is similar to the first class lever because it has an effort force between a
fulcrum and load.
c. The pulley is similar to the first class lever because it has load between a fulcrum and
effort force.
d. There are no similarities between the pulley and first class lever.
Week: Two
Lesson: Three
Topic: Simple Machines – Wedge and Screws
Content
A wedge is simply a triangular tool, often made of metal, wood, stone, or plastic. It is thick on one
end and tapers to a thin or sharp edge on the other end. A wedge is an inclined plane (or two
inclined planes put together to form a triangle) that moves. A wedge may be attached to a handle
to make it easier to use. Good examples of wedges are nails, knives, axes, and your teeth.
source: (eSchoolToday, 2008)
A wedge is used to:
- cut things (knife)
- split objects (axe)
- tighten and to hold back (doorstopper)
- hold together (nail)
- scrape (blades on the snowplow or farm grader)
How wedges work?
Wedges work by changing direction and force applied to it. Here is an illustration: Diagram of
change in direction and force.
source: (eSchoolToday, 2008)
The force applied to the thick end of the wedge overcomes the resistance of the wood. The force
is directed downwards, but the wedge directs the force sideways as it drives into the wood. A
wedge may be a single wedge or double wedge. Each does a slightly different job. An axe is a
double wedge and a chisel is a single wedge.
How do wedges make work easier?
Wedges make work easier by increasing distance and decreasing force. If you had a longer
wedge and a shorter wedge, then the longer wedge would make work easier. The longer wedge
has more mechanical advantage than the shorter wedge. The reason for this is because if a wedge
makes work easier by increasing distance and decreasing force, then the longer one will have
more distance which would mean less force. So, if you wanted to split a piece of wood with an
ax, you should probably use the longer ax.
The Screw
A screw is simply an inclined plane around a cylinder. To describe this better, you can view it as
a cylinder with a head (solid top) at one end and a pointed tip (like a nail) at the other end. More
importantly, it has ridges winding around it. The correct term for the ridges (or grooves) around
the shaft or cylinder is the thread.
source: (eSchoolToday, 2008)
The distance between threads is the same for each screw but is different on other screws. The
distance between threads is called a Pitch. Screws are useful for holding things together. They can
pull or push an object together. They can be used to lift heavy items and tighten things.
Examples of Screws
Some good examples of screws are
bolts, screws, bottle tops, guitar
tuners, light bulbs, faucet taps, and
cork openers.
Mechanical Advantage of Screws
A screw having threads close together has a mechanical advantage over those with wider spaces.
They will take less force but more turns. Those with wider spaces will take more force but less
turns.
Reference
https://eschooltoday.com/learn/the-pulley/
https://eschooltoday.com/learn/the-wedge-ramp/
https://www.britannica.com/technology/simple-machine
Week: Two
Lesson: Three
Worksheet: Simple Machines – Wedge and Screws
1. Which simple machine is used to hold objects together?
A. wedge
B. wheel and axle
C. inclined plane
D. screw
2. The simple machine used on a flagpole to help when the flag is raised is called
A. wedge
B. pulley
C. wheel and axle
D. incline plane
3. Sarah wants to split a log. Which simple should Sarah use?
A. wedge
B. wheel and axle
C. inclined plane
D. screw
4. The screwdriver shown in the picture below is that of a
A. wheel and axle
B. lever
C. screw
D. inclined plane
5. Which simple machine turns the image shown below
A. screw
B. wheel
C. pulley
D. wheel and axle
6. A pulley is
A. a bar used to lift heavy objects
B. a wheel with a groove for a rope
C. made of two incline planes
D. a lever with an arm and a fulcrum
7. Which of the following machine has a block and tackle pulley
A. sand truck
B. washing machine
C. crane
D. tractor
8. Which is not TRUE about a block and tackle pulley?
A. it is a compound pulley
B. it is a fixed pulley
C. it is a combination of pulleys
D. it is used for lifting heavy objects
9. Mark wants a bucket of sand up a three-story building. Which of the following machines
will be best suited for Mark to use
A. a pulley
B. a wheel barrow
C. a wheel and axle
D. an inclined plane
10. The picture shows an example of a
A. screw
B. wheel and axle
C. wheel
D. axle
Name the simple machines shown in the pictures.
Week: Three
Lesson: One
Worksheet: Machines – Review
Match the key terms listed in the word-bank with the correct definition. Write the correct letter in
the space provided.
A. Simple Machine B. Wheel C. Axle D. Friction
E. Mechanical Advantage F. Radius G. Diameter H. Circumference
J. Force K. Work L. Effort M. Load
1. ______ Using a force to move an object a distance.
2. ______ A shaft that is fixed to the center of a wheel, or placed through the center of a wheel,
allowing the wheel to rotate freely.
3. ______ The distance from the center of a circle to the outside edge.
4. ______ The object or weight being moved or lifted.
5. ______ A push or a pull.
6. ______ The resistance that one surface or object encounters while in contact with and moving
across another.
7. ______ A circular object that revolves with or around an axle.
8. ______ A device that transmits or modifies force or motion.
9. ______ The distance through the center of a circle from one side to another.
10. ______ A force applied to a machine to do work.
11. ______ The amount a machine multiplies force.
12. An example of a inclined planes are
a. gliders and rockets
b. ramps and wedges
c. wheels and axles
d. screws and gliders
13. Another name for the pivot of a lever is the:
a. torque
b. turning angle
c. fulcrum
14. The load in a lever is the:
a. focus of muscular contraction
b. weight to be moved
c. pivot point of the lever
15. The effort of a lever is the:
a. exertion of muscular activity
b. weight to be moved
c. turning point
16. An example of a first order lever with effort, fulcrum and load in that order is:
a. scissors
b. a bottle opener
c. a fishing rod
17. An example of a second order lever with fulcrum, load and effort in that order is a:
a. hammer pulling out a nail
b. wheelbarrow
c. shovel shifting soil
18. The rule for mechanical advantage of a Lever is:
a. Load / Effort
b. Effort arm length / Load arm length
c. both of the above
19. The rule for the mechanical advantage of a wheel and axle is:
a. Circumference of wheel / Circumference of axle
b. Axle diameter / Wheel diameter
c. Wheel diameter / Axle diameter
20. If a simple machine requires an effort of 20 newtons to lift a load of 100 newtons, its
mechanical advantage is:
a. 5
b. 5N
c. 5MA
21. Which is not a complex machine
a. car
b. vacuum cleaner
c. wheelbarrow
d. airplane
22. What is the purpose of a simple machine?
a. to change potential energy into kinetic energy
b. to produce inertia
c. to make work easier and use less force
d. to test force
Study the diagrams below, then answer question 23.
23. Which ramp requires a greater distance but less force?
a. A
b. B
c. C
24. Name the simple machines shown in the pictures below.
25. How much force is required to accelerate a 2 kg mass at 3 m/s2 ?
26. Given a force of 100 N and an acceleration of 10 m/s2 , what is the mass?
27. What is the acceleration of a 10 kg mass pushed by a 5 N force?
28. Given a force of 88 N and an acceleration of 4 m/s2 , what is the mass?
29. How much force is required to accelerate a 12 kg mass at 5 m/s2 ?
30. Given a force of 10 N and an acceleration of 5 m/s2 , what is the mass?
References
Simple Machines Quiz - Qld Science Teachers
F=MA WORKSHEET (sfponline.org)
Simple Machines Worksheets (easyteacherworksheets.com)
Week: Three
Lesson: Two
Topic: Forces and Motion
Content
A force is a push or a pull acting upon an object as a result of its interaction with another object.
Force is a quantity that is measured using the standard metric unit known as the Newton - symbol
(N).
Some Effects of Forces
- Force can make a body that is at rest move.
- It can stop a moving body or slow it down.
- It can accelerate the speed of a moving body.
- It can also change the direction of a moving body along with its shape and size.
Formula for Force
The quantity of a force is expressed by the vector products of mass (m) and acceleration (a). The
equation or the formula for force can be mathematically expressed in the form of:
F = ma Where: F = Force
m = mass
a = acceleration
Types of Force
There are two types of forces based on their applications:
- Contact Force
- Non-Contact Force
Contact Force
Forces that act on a body either directly or through a medium are called contact forces. These
forces are involved only when two objects physically interact or touch each other.
Types of Contact Force
There are different types of contact forces like normal force, spring force, applied force and
tension force.
1. Normal force is when nothing is happening like a book lying on a table because gravity is
pulling it down.
2. Spring force is created by a compressed or stretched spring that could push or pull.
3. Applied force is when someone is applying a force to an object, for example a horse pulling
a rope or a boy throwing a snowball.
4. Tension force is a force that is applied to a cable or a wire. Tension force causes a force to
pull equally in each direction.
5. Frictional force is another type of contact force, which acts between a pair of surfaces in
contact and tends to oppose the motion of one surface over the other.
Examples of contact forces are muscular, mechanical and frictional forces.
Non-contact Force
Forces that act through spaces without making direct contact with the body are called non-contact
forces.
Types of Non-contact Forces
1. Gravitational force is responsible for bringing the items we toss into the air back to earth.
When an object is resting on a surface it is exerting a downward force equal to its weight
and this downward force is known as Gravitational force.
2. The electrostatic force is very similar to the gravitational force, the difference here is that
gravitational force acts between masses and an electrostatic force acts between two charged
bodies.
3. The force exerted by a magnet on other magnets is called magnetic force.
Magnetic and electrostatic forces act on objects from a distance, that’s the reason they are non-
contact forces. The strength of gravity is an attractive force that is exerted by the Earth on objects,
which makes them fall to the land. The weight of a body is the force that is pulled by the earth
towards the center.
Examples of non-contact forces are.
1. An apple falling down from a tree is one of the best examples of non-contact force.
2. Iron pins attracted in the presence of a magnet bar without any physical contact.
3. Falling of raindrops on earth is also an example of non-contact force.
4. The charging of the hair and attraction of paper bits towards it.
5. Two magnets are placed close to each other is also a non-contact force example.
References
https://byjus.com/physics/force/
https://study.com/academy/lesson/what-is-the-formula-for-force-definition-lesson-
quiz.html#:~:text=The%20formula%20for%20force%20says,(%20m%2Fs2%20).
https://www.physicsclassroom.com/class/newtlaws/Lesson-2/The-Meaning-of-Force
Week: Three
Lesson: Two
Worksheet: Forces and Motion
1. Which of the following is the best example to explain that the force on an object may
change its shape?
A. A ball of dough rolled into a roti
B. Pressing a rubber ball kept on table
C. Making model using clay
D. All of the above
2. A ___________ exerted by an object on another is a force.
A. Push or pull
B. Contact or non-contact force
C. Pressure
D. Magnitude
3. The force exerted by the earth to pull the object towards itself is called
A. electrostatic force
B. gravitational force
C. muscular force
D. contact force
4. Muscular force is also called ___________ force.
A. non-contact
B. contact
C. gravitational
D. magnetic
5. Force changes the
A. motion of body
B. speed of body
C. shape of body
D. all of these
6. The force exerted by our muscle is called
A. electrostatic force
B. muscular force
C. gravitational force
D. non-contact force
7. Leaves fall down on the ground due to
A. electrostatic force
B. magnetic force
C. gravitational force
D. muscular force
8. Which one of the following forces is a contact force?
A. Force of gravity
B. Magnetic force
C. Force of friction
D. Electrostatic force
9. A ball rolling on the ground slows down and finally stops. This is because of
A. Force
B. Less force applied
C. Friction
D. None of the above
10. If in a tug-o-war, when two teams are pulling a rope, and the rope does not move towards
any team, it implies that
A. Equal force is being applied in the same direction
B. Equal Force is being applied in opposite direction
C. No force is applied in any direction
D. Cannot be explained
Forces and Motion
F C I R Q E R N U S D F U Q V
L A N O I T A T I V A R G X L
C O O M A S S F S J Z M U A M
U I I D G N K P D K A N C P U
P E T B I T O E U G I I P U S
Z T A A N R E T N S N A D L C
F H R G T P E E W A H F E L U
L E E M S S T C H E I C E S L
I M L T X I O C T U N M C G A
H E E W C M E R O I N R R A R
N N C J X M B L T E O C O U R
O U C K B A C V Z C Z N F C D
D I A Z E G P M Y F E Z R S K
F R I C T I O N A L G L S B D
T C A T N O C B J E T K E E T
ACCELERATION PULL SPEED
GRAVITATIONAL NEWTON
MECHANICAL MASS MAGNETIC
CONTACT DIRECTION
ELECTROSTATIC MUSCULAR PUSH FORCE FRICTIONAL
Week: Three
Lesson: Three
Topic: Motion
Content
Motion makes things move or go round. Motion also makes objects speed up or slow down.
Motion may be divided into three basic types — translational, rotational, and
oscillatory. Motion that results in a change of location is said to be translational. Motion that is
repetitive and fluctuates between two locations is said to be oscillatory. Motion that occurs when
an object spins is said to be rotational. Example: The Earth is in a constant state of motion.
How can we measure different amounts of motion or figure out where a flying bullet or a soaring
space rocket is going to end up? Isaac Newton's work helps us to understand the relationship
between forces and motion. It also lets us calculate how things will move when we apply forces
to them.
Newton’s three Laws of Motion
Sir Isaac Newton (1642–1727) summarized how things move with three simple laws. They are
often simply called Newton's laws.
1. Things that are still stay still and things that are moving keep moving with a steady
speed unless a force of some kind pushes or pulls on them.
2. When a force acts (pushes or pulls) on an object, it changes the object's speed or direction
(in other words, makes it accelerate). The bigger the force, the more the object
accelerates.
3. When a force acts on an object, there's an equal force (called a reaction) acting in the
opposite direction. This law is sometimes written "action and reaction are equal and
opposite."
Measuring Motion
There are four main ways of measuring the motion of an object. We can find the speed and
velocity, acceleration, momentum, and kinetic energy of an object to determine its motion.
1. The speed of an object tells us how fast or slow an object is moving. The velocity is the
speed of an object in a particular direction, if the direction changes, the speed, and
velocity also change.
2. Acceleration is the measurement of change in an object's velocity. When you press down
on the gas pedal in a car, the car surges forward going faster and faster. This change in
velocity is acceleration. A free-falling object is an object that is falling under the sole
influence of gravity. A free-falling object has an acceleration of 9.8 m/s2, downward on
Earth.
3. It takes energy to make something move, and the faster it goes the more energy it needs.
In other words, the energy feeds speed. The energy something has when it's moving is
called kinetic energy.
4. Momentum refers to the quantity of motion that an object has. A sports team that is on
the move has momentum. If an object is in motion (on the move) then it has momentum.
Finding the Force of Objects
In the previous lesson, we learned that the force of an object can be found by multiplying the
mass of the object by its acceleration. Now let us look at how to solve problems involving force.
F = ma Where: F = Force
m = mass
a = acceleration
Example 1:
If a rubber ball mass of 0.25 kg is falling freely and hits the ground, what force does it have?
Answer: F = 0.25 kg x 9.8 m/s2
F = 2.45 N
NB: 1 N is equivalent to 1 kg m/s2.
Reference
Motion – The Physics Hypertextbook
Momentum (physicsclassroom.com)
https://www.britannica.com/science/Newtons-laws-of-motion
https://www.physicsclassroom.com/Physics-Tutorial/Newton-s-Laws
https://www.physicsclassroom.com/class/1DKin/Lesson-1/Acceleration
Week: Three
Lesson: Three
Worksheet: Forces and Motion
Calculate the force in the following problems by using the equation:
Force = mass x acceleration F = m a
Be sure to (1) ALWAYS write the equation
(2) Plug in the numbers and units,
(3) Give the answer with the correct units.
1. A man hits a golf ball (0.2 kg) which accelerates at a rate of 20 m/s2. What amount of force
acted on the ball?
2. You give a shopping cart a shove down the aisle. The cart is full of groceries and
has a mass of 18kg. The cart accelerates at a rate of 3 m/s2. How much force did you exert
on the cart?
3. The wind pushes a paper cup along the sand at a beach. The cup has a mass of 0.025 kg
and accelerates at a rate of 5 m/s2. How much force is the wind exerting on the cup?
4. You push a friend sitting on a swing. She has a mass of 50 kg and accelerates at a
rate of 4 m/s2. Find the force you exerted.
5. How much force would it take to push another, larger friend who has a mass of 70 kg to
accelerate at the same rate of 4 m/s2?
6. A worker drops his hammer off the roof of a house. The hammer has a mass of 9kg, and
gravity accelerates it at the usual 9.8 m/s2. How much force does the earth apply to the
hammer?
7. A man hit a tennis ball with a force of 45N. The ball accelerated at a rate of 9m/s2. What
is the mass of the ball?
8. A wooden plank has a mass of 100kg. A force of 20 N was used to move it. What is its
acceleration?
9. A force of 10N was used to move a bag of potatoes that has a mass of 50kg. Calculate the
acceleration.
10. A wheelbarrow of sand was pushed with a force of 95N and accelerated at a rate of 5m/s2.
Determine the mass of the wheelbarrow.
Week: Four
Lesson: One
Topic: Review of Forces and Motion
Work all the questions in this lesson to practice some more of what was done on forces and
motion.
1. Which of the following is an example of a measurement of acceleration?
A. 4 m/s
B. 4 m/s 2
C. 4 m
D. 4 m/s3
2. Which of the following sets of measurements can be used to calculate acceleration?
A. change in time, initial and final velocity
B. change in time and change in position
C. time and distance
D. time, distance and position
3. What do the symbols Vi and Vf represent?
A. velocity in two different directions
B. the velocity of object i and object f
C. change in velocity
D. initial velocity and final velocity
4. A fox is traveling at a velocity of 2.7 m/s. 3.5 seconds later it is traveling at a velocity of
4.8 m/s. What is the acceleration of the fox?
A. 0.6 m/s2
B. 0.75m/s2
C. 1.75m/s2
D. 0.9m/s2
The figure shows the forces acting on a car moving at a constant speed.
5. Which force would have to increase to make the car accelerate?
A. A
B. B
C. C
D. D
The figure below shows the horizontal forces acting on a car.
6. Which one of the statements describes the motion of the car?
A. It will be slowing down
B. It will be stationary
C. It will have a constant speed
D. It will be speeding up.
7. If an object moves with a constant velocity, we can conclude that
A. it is moving toward its natural place.
B. there are no forces acting on it.
C. there is no unbalanced (net) force acting on it.
D. it has very large inertia.
8. According to Newton’s first law of motion, a moving object that is not acted on by an
unbalanced force will
A. remain in motion.
B. eventually, come to a stop
C. change its momentum.
D. accelerate.
9. A man hits a golf ball (5 kg) which accelerates at a rate of 20 m/s2. What amount
of force is acting on the ball?
A. 100N
B. 100m/s2
C. 4N
D. 4m/s2
10. You give a shopping cart a shove down the aisle. The cart is full of groceries and
has a mass of 20.5 kg. The cart accelerates at a rate of 4 m/s2. How much force did you
exert on the cart?
A. 5N
B. 80N
C. 82N
D. 82 m/s2
11. How much force is needed to accelerate a 66 kg skier at 2 m/sec2?
12. What is the force on a 1000 kg elevator that is falling freely at 9.8 m/sec2?
13. What is the acceleration of a 50 kg object pushed with a force of 500 Newton?
14. The mass of a large car is 1000 kg. How much force would be required to accelerate the
car at a rate of 3 m/s2?
15. A 50 kg skater pushed by a friend accelerates 5 m/sec2. How much force did the friend
apply?
16. A force of 250 N is applied to an object that accelerates at a rate of 5 m/sec2. What is the
mass of the object?
17. A bowling ball rolled with a force of 15 N accelerates at a rate of 3 m/sec2; a second ball
rolled with the same force accelerates 4 m/sec2. What are the masses of the two balls?
18. If a 60 kg person on a 15 kg sled is pushed with a force of 300 N, what will be a person’s
acceleration?
19. A force of 20 N acts upon a 5 kg block. Calculate the acceleration of the object.
20. An object of mass 300 kg is observed to accelerate at the rate of 4 m/s2. Calculate the
force required to produce this acceleration.
21. A 5 kg block is pulled across a table by a horizontal force of 40 N with a frictional force
of 8 N opposing the motion. Calculate the acceleration of the object.
22. An object of mass 30 kg is in free fall in a vacuum where there is no air resistance.
Determine the acceleration of the object.
Week: Four
Lesson: Two
Topic: Friction
Content
Friction is a force between two surfaces that are sliding, or trying to slide, across each other. For
example, when you try to push a book along the floor, friction makes this difficult. Friction always
works in the direction opposite to the direction in which the object is moving, or trying to move.
Friction always slows a moving object down.
source: (Byju’s, 2019)
The amount of friction depends on the materials from which the two surfaces are made. The
rougher the surface, the more friction is produced. Friction also produces heat. If you rub your
hands together quickly, you will feel them get warmer.
Types of friction
There are two main types of friction, static friction, and kinetic friction. Static friction operates
between two surfaces that are not moving relative to each other, while kinetic friction acts between
objects in motion.
Static friction
Static friction is a force that keeps an object at rest. Static friction is the friction experienced when
individuals try to move a stationary object on a surface, without actually triggering any relative
motion between the body and the surface on which it is. It can be explained as the force of friction
which precisely balances the applied force for the duration of the stationary state of the body. The
static frictional force is self-regulating, i.e. static friction will at all times be equivalent and
opposite to the force applied.
source: (Byju’s, 2019)
Kinetic friction
Kinetic friction is defined as a force that acts between moving surfaces. A body moving on the
surface experiences a force in the opposite direction of its movement. The magnitude of the force
will depend on the coefficient of kinetic friction between the two materials.
source: (Byju’s, 2019)
Static Electricity
Static electricity is the result of an imbalance between negative and positive charges in an object.
These charges can build up on the surface of an object until they find a way to be released or
discharged. The rubbing of certain materials against one another can transfer negative charges or
electrons. For example, if you rub your shoe on the carpet, your body collects extra electrons. The
electrons cling to your body until they can be released.
source: (American Physical Society 2019)
Applications of Static Electricity
Static electricity has several uses in the real world. One main use is in printers and photocopiers
where static electric charges attract the ink, or toner, to the paper. Other uses include paint
sprayers, air filters, and dust removal.
Static electricity can also cause damage. Some electronic chips, like the kind that are in
computers, are very sensitive to static electricity. There are special bags to store electrical
components in so they don't get destroyed by static electricity. Also, people that work with these
kinds of electronics wear special straps that keep them "grounded" so they won't build up a static
charge and ruin the electronic components.
Reference
https://www.livescience.com/51656-static-electricity.html
https://byjus.com/physics/staticfriction/#:~:text=Static%20friction%20is%20a%20force,surface
%20which%20it%20is%20on.
https://www.livescience.com/37161-what-is-friction.html
Week: Four
Lesson: Two
Worksheet: Friction
1. If two charges repel each other, the two charges must be
A. positive and positive.
B. negative and negative.
C. positive and negative
D. Either (a) or (c)
2. An object becomes charged when the atoms in the object gain or lose
A. protons.
B. electrons.
C. neutrons.
D. All of the above
3. If you rub a glass rod with a piece of silk, the rod becomes positively charged. This means
that
A. friction destroyed electrons in the rod.
B. the silk has become negatively charged.
C. protons have moved to the rod.
D. glass attracts more protons
4. Objects can become charged by
A. friction.
B. convection
C. conduction.
D. All of the above
5. When you rub a balloon on your hair, the balloon becomes charged by
A. friction.
B. induction.
C. conduction.
D. reduction.
6. Clothes stick together when you pull them out of the dryer because
A. clothing is a conductor.
B. they are not charged.
C. clothing is an inductor.
D. of static electricity.
7. Which of the following is NOT TRUE about static friction?
A. it keeps an object at rest
B. it operates between two surfaces that are moving relative to each other
C. it is a self-regulating force
D. it is all times equivalent to the opposite force applied
8. Static electricity is an imbalance between
A. electrons and protons
B. protons and neutrons
C. electron and neutrons
D. protons, neutrons and electrons
9. Friction always works in the ……….. direction
A. same
B. opposite
C. perpendicular
D. downwards
10. The amount of friction depends on
A. static electricity
B. the number of electrons
C. the number of protons
D. the materials from the surfaces are made
Forces and Motion
DIRECTION ELECTRONS FORCES FRICTION
FRICTIONAL KINETIC MAGNITUDE MOTION OPPOSITE
RUBBING STATIC
U L O I G P E S N S M G C W O
O M A T H D P L V W N N R O Z
P O G N I B B U R H O H G S Q
R T P A O E D U T I N G A M T
R I J P K I N E T I C S P O L
J O S N O R T C E L E F L E O
T N I V Q S E C R O F M P D Z
E L E C T R I C I T Y H G K Q
W V O C I T A T S R J F N X R
W D G D C D X R E C F U C V T
Week: Four
Lesson: Three
Topic: Importance of Friction
Content
Importance of fiction
Friction changes or tends to change the moving object from moving by reducing its speed to zero
or make stop the stationary objects from moving. The force exerted by friction is called the
frictional force. Since friction is a resistance force that slows down or prevents motion, it is
necessary for many applications where you might want to hold items or do things and prevent
slipping or sliding. In those cases, there is an advantage of having friction. Quite often uses of
friction can be seen from how things would be without friction. If there was no friction, you would
not be able to walk, drive a car, or hold objects. Pens and pencils would not work. Friction is also
necessary to stop a car or bike through the use of brakes.
Advantages of Friction
Walking
You will not be able to walk without the friction between your shoes and the ground. As you try
to step forward, you push your foot backward. Friction holds your shoe to the ground, allowing
you to walk. Consider how difficult it is to walk on slippery ice, where there is little friction.
Writing
Writing with a pencil requires friction. You could not hold a pencil in your hand without friction.
It would slip out when you tried to hold it to write. The graphite pencil led would not make a mark
on the paper without friction. A pencil eraser uses friction to rub off mistakes written in pencil
lead. Rubbing the eraser on the lead wears out the eraser due to friction, while the particles worn
off gather up the pencil lead from the paper.
Driving a car or riding a bicycle
Your car would not start moving if it wasn't for the friction of the tires against the street. With no
friction, the tires would just spin. Likewise, you could not stop without the friction of the brakes
and the tires.
source: (Teachoo, 2020)
Disadvantages of friction
- Friction produces unnecessary heat leading to the wastage of energy.
- The force of friction acts in the opposite direction of motion, so friction slows down the
motion of moving objects.
- Forest fires are caused due to the friction between tree branches.
- A lot of money goes into preventing friction and the usual wear and tear caused by it by
using techniques like greasing and oiling
source: (Teachoo, 2020)
Ways of reducing friction
- For objects that move in fluids such as boats, planes, cars, etc, the shape of their body is
streamlined to reduce the friction between the body of the objects as the fluid.
- By polishing the surface, as polishing makes the surface smooth and friction can be
reduced.
- Using lubricants such as oil or grease can reduce the friction between the surfaces.
- When objects are rolled over the surface, the friction between the rolled object and surface
can be reduced by using ball bearings
source: (Teachoo, 2020)
Reference
https://byjus.com/questions/what-are-the-methods-of-reducing-friction-explain/
https://www.google.com/search?q=disadvantages+of+friction&hl=en&source=lnms&tbm=isch&
sa=X&ved=2ahUKEwi6y5vxm9XsAhWmwVkKHZSqD50Q_AUoAXoECBwQAw&biw=1366
&bih=625#imgrc=tjivTOaaf-6BAM
https://www.toppr.com/ask/question/state-two-advantages-and-disadvantages-of-friction/
Week: Four
Lesson: Three
Worksheet: Importance of Friction
Short answer questions
1. What is the force responsible for wearing out of bicycle tires?
2. Is the friction the same for all objects?
3. Why are the wheels of vehicles made circular?
4. What is the direction of the force of friction acting on a moving object?
5. What is the use of lubricants?
6. Which surface does produce more friction—smooth or rough surface?
7. Why is it difficult to walk on the wet marble floor?
8. Which force helps us to write on the paper or blackboard?
9. Oil, creams, and grease are called lubricants. Why?
10. Can we reduce friction to zero?
Complete the wordsearch below.
Friction
P G N I L I O Q O G F S R V M
N O I T A C I R B U L E E S O
L M L E K S C K M G D U D T T
E G N I K L A W R O I Q U C I
P S M E S J T E S T U I C E O
G M Q Y B H A A D E L N I J N
K H V R G S I R Y X F H N B H
L U B R I C A N T S Y C G O L
Y W L N L M R S G V Y E N Y G
P F G D B F O R C E S T I Z F
FLUID FORCES GREASING
LUBRICANTS LUBRICATION MOTION
OBJECTS OILING POLISHING
REDUCING TECHNIQUES WALKING
Integrated Science Grade 8
Week: Five
Lesson: One
Topic: Review Forces and Motion
A force is a push or a pull in a specific direction and calculates it, we use the
following formula:
F = ma Where F = force in
newtons m =
mass in kg a =
acceleration in
m/s2
Example: If a rubber ball mass of 0.25 kg is falling freely and
hits the ground, what force does it have?
Answer: F = (0.25 kg) (9.8 m/s2)
F = 2.45 N
Provide the answers to the questions below.
1. The resistance that one surface or object encounters when moving over or against
another is called:
a. force
b. friction
c. unbalanced force
d. motion
2. Friction is a:
a. balanced force
b. unbalanced force
c. type of motion
d. type of direction
3. Friction is always __________ to the normal force in a moving object.
a. proportional
b. perpendicular
c. unbalanced
d. proportional and perpendicular
4. The friction force that exists between two unmoving objects is called:
a. the coefficient of dynamic friction
b. the coefficient of static friction
c. the coefficient of kinetic friction
d. the coefficient of unmoving objects
5. Which of the following is NOT a type of friction?
a. static
b. sliding
c. rolling
d. touching
6. When you push or pull an object, you are applying:
a. force
b. friction
c. gravity
d. electromagnetism
7. Which of the following is NOT a force?
a. friction
b. gravity
c. electromagnetism
d. none of the above
8. What is a newton (N)?
a. the unit by which scientists measure gravity
b. the unit by which scientists measure acceleration
c. the unit by which scientists measure magnitude D. the unit by which scientists
measure force
9. Which equation represents how force is calculated?
a. a = f * m
b. f = m * a
c. m = f * a
d. none of the above
10. When the net sum of all forces acting on an object is zero, we call that: A. being at
rest
a. acceleration
b. magnitude
c. motion
11. What force would be required to accelerate a 10 kg bowling ball at a rate of 3 m/s2?
12. If a car with a mass of 4,000 kg is accelerating at a rate of 2 m/s2 and hits a tree, what
force does it have?
13. If a freely falling rock hits the ground with a force of 245 Newton, what is its mass?
14. If a ball if it has a mass of 0.50 kg and hits the fielder's glove with a force of 4.9
Newton, what is its acceleration?
15. If a truck if it is accelerating at a rate of 5 m/s2 and hits a parked car with a force of
16,000 Newton, what is its mass?
ACROSS DOWN
3. Force multiplied by distance 1. The SI unit of force
4. A lever rotates around this point 2. The SI unit of work
5. Quantity of work done per unit of time 4. This reduces the efficiency of a machine by
creating heat energy
6. This is an inclined plane wrapped around a cylinder 8. SI unit or power
7. Machines make work easier by reducing force,
but increase the ______ required
10. The value of work output divided by the work
input.
9. The number of times a force is multiplied due to a
machine is its mechanical ______.
11. An inclined plane is an example of a _____
machine.
12. An automobile is an example of a _____ machine
3
4
5
6
7
8
9 10
11
12
1 2
Week: Five
Lesson: Two
Topic: Matter
Content
Matter is everything that makes up the universe. In other words, matter is anything that takes up
space (volume) and has mass.
The particulate theory of matter states that:
- all matter is made up of particles.
- the particles have spaces between them.
This theory can be used to help explain:
- the properties of matter.
- what happens during the physical changes between the states of matter.
The kinetic theory of matter is another theory that helps to explain why matter exists in different
phases (solid, liquid, and gas) and how matter can change from one phase to the next. This theory
states that:
- Matter is made up of particles that are constantly moving.
- All particles have energy, but the energy varies depending on the temperature. This in turn
determines whether the substance exists in the solid, liquid, or gaseous state. Matter in the
solid phase have the least amount of energy, while gas particles have the greatest amount
of energy.
- The temperature of a substance is a measure of the kinetic energy of the particles.
Kinetic energy is energy that an object has because of its motion.
Temperature is the term used to explain how hot or cold an object is.
- A change in phase may occur when the energy of the particles is changed.
States of Matter
There are four natural states of matter: Solids, liquids, gases and plasma.
Solid Liquid Gas Plasma
Properties of Matter
Property
Solid Liquid Gase
Arrangement of
Particles
Particles are arranged very
close to each other in definite
order.
Particles are more loosely
packed than in a solid.
Particles have a great
deal of space between
them.
Shape and
Volume
Definite or fixed shape and
volume.
Have a fixed volume but
not a fixed shape. Take
the shape of their
container.
Do not have a fixed
shape or volume. Take
the shape of their
container.
Movement particles are packed tightly
together so they don't move
much. The particles only
vibrate therefore, particles in
Particles are free to move
over each other, but are
still close to each other.
particles move in
random motion with
little or no attraction to
each other. These
a solid have very low kinetic
energy.
particles have high
kinetic energy.
Compressibility Least compressible Compressibility of liquids
are slightly higher than
that of solids.
High compressibility
Density High density because the
particles are packed very
close.
Less dense that solids Very low density
Plasma
Plasma is not a common state of matter here on Earth. Stars are essentially superheated balls of
plasma. Plasma consists of highly charged particles with extremely high kinetic energy. The noble
gases (helium, neon, argon, krypton, xenon and radon) are often used to make glowing signs by
using electricity.
Changes in the States of Matter
The processes involved in changing the states of matter are:
1. Melting is the process where a solid change to its liquid state at a certain temperature
(called the melting point).
2. Freezing is the process where a liquid changes to its solid state at a certain temperature
(called freezing point).
3. Vaporization, also called evaporation is the process whereby particles in the liquid state
gain sufficient energy to enter the gaseous state.
4. Condensation is the process by which a gas or vapour changes to liquid.
5. Sublimation is a process of conversion of a substance from the solid to the vapour state
without its becoming liquid.
6. Deposition is the process in which a gas changes directly to a solid without going
through the liquid state. It is the opposite of sublimation
Reference
https://www.le.ac.uk/se/centres/sci/selfstudy/particle01.html
https://www.scoe.org/files/ngss-particle-model.pdf
https://www.livescience.com/46506-states-of-matter.html
Week: Five
Lesson: Two
Worksheet: Matter
Circle the correct response to each question.
1. A solid is a state of matter that has a(n)
A. indefinite volume and an indefinite shape.
B. definite volume and a definite shape.
C. definite volume and an indefinite shape.
D. indefinite volume and a definite shape.
2. An uncovered pot of soup is simmering on a stove, and there are water droplets on the
wall above the back of the stove. What sequence can you infer has occurred?
A. melting, then boiling
B. freezing, then thawing
C. vaporization, then condensation
D. condensation, then vaporization
3. In which state of matter are particles packed tightly together in fixed positions?
A. gas
B. solid
C. liquid compound
4. The state of matter in which particles are arranged in either a crystalline or an
amorphous form is
A. liquid.
B. gas.
C. solid.
D. plasma
5. Particles of a liquid
A. are tightly packed together and stay in a fixed position.
B. have no viscosity.
C. decrease in volume with increasing temperature.
D. are free to move in a container but remain in close contact with one another.
6. In which state of matter do the particles spread apart and fill all the space available to
them?
A. crystalline
B. liquid
C. gas
D. solid
7. The change from liquid to solid, or the reverse of melting, is called
A. condensation
B. boiling
C. freezing
D. ionization
8. What is vaporization?
A. a gas becoming a liquid
B. a liquid becoming a solid
C. a gas becoming a solid
D. a liquid becoming a gas
9. During the process of sublimation,
A. a solid turns directly into a gas.
B. a solid turns into a liquid
C. a gas turns directly into a solid.
D. a liquid turns into a gas
10. The opposite of vaporization is called
A. condensation
B. sublimation
C. evaporation
D. freezing
11. Identify the state of matter described by the statements below. Many of these have
more than one answer! (Use S, L or G in the spaces.)
____ not easily compressible
____ rigid – particles locked into place
____ flows easily
____ compressible
____ lots of free space between particles
____ does not flow easily
____ assumes the shape of the part of the container which it occupies
____ particles can move past one another
____ retains a fixed volume and shape
____ assumes the shape and volume of its container
____ little free space between particles
12. Match each Description on the left with the correct change of state on the right.
You may use some changes of state more than once.
Term Descriptor
Ice is left out on the counter
A.
Sublimation
Frost forms on the window on a cold day
B.
Condensation
Water is left in a freezer
C.
Evaporation
Clothes are left out to dry
D.
Deposition
Dry ice is used to create fog
E.
Melting
The bathroom mirror gets fogged up after a shower
F.
Solidification
A pond gets shallower at the end of a long hot summer
Your hair was wet when you left the house, but dries by the time you get to school
The ice cream you are eating drips down your arm
A full pot of soup fills only half of the pot after summering for 2 h
Liquid glass cools and hardens
A cold drink is wet on the outside of the glass
Week: Five
Lesson: Three
Topic: Atoms and Elements
Content
In lesson one we said that all things are made up of matter and that matter is made up of
particles. The particle or particles that makes up matter is the atom.
Atom
Atoms are the basic unit or building-block of all matter. Atoms can be sub-divided into protons,
neutrons and electrons.
Structure of an Atom
source: (LifeScience Reference Editor, 2017)
Parts of an Atom
There are two parts to an atom
1. At the centre of an atom is a nucleus made up of two types of particles called protons and
neutrons.
- Protons have a positive (+) electrical charge.
- Neutrons are about the size of protons but have no charge (0).
2. Electrons are much smaller than protons and neutrons. They have a negative (-) electrical
charge and they orbit (move around) the nucleus.
Protons and neutrons are heavier than electrons and reside in the nucleus at the center of the
atom. Electrons are extremely lightweight and exist in a cloud (shell) orbiting the nucleus.
Protons and neutrons have approximately the same mass. However, one proton is about 1,835
times more massive than an electron. Atoms always have an equal number of protons and
electrons. Adding a proton to an atom makes a new element while adding a neutron makes an
isotope, or a heavier version, of that atom.
Scientists who contributed to the discovery of the atom
Year Scientist Model of the Atom
1807 Dalton
Atom is a hard dense sphere
1903 Thompson Atom is a mass of positive
charges containing negative electrons
1911 Rutherford Atoms has dense nucleus surrounded by
electrons
1913 Bohr Atom has a dense nucleus. Electrons
move in fixed orbit around the nucleus
Reference
Blackman, S., Bernard, M., Dalgety, F., & Sadoo, d. S. (2000). Science in Daily Life Bk. 2.
Georgetown, Guyana: Ministry of Education, Guyana.
https://courses.lumenlearning.com/suny-earthscience/chapter/atoms-to-molecules/
https://www.livescience.com/37206-atom-definition.html
Week: Five
Lesson: Three
Worksheet: Composition of Matter
All matter is made up of _________________and atoms are made up of smaller particles.
The three main particles making up an atom are the -
___________________, __________________,__________________.
Electrons spin around the center, or_________________, of atoms, in the same way the moon
spins around the earth. The nucleus is made up of __________________and
____________________.
Electrons contain a ____________________charge, protons a _____________________ charge.
Neutrons are ___________________
-- they have neither a positive nor a negative charge.
Each atom has a specific number of electrons, protons and neutrons. No matter how many
particles an atom has, the number of electrons usually needs to be the ____________________as
the number of protons. If the numbers are the same, the atom is called balanced, and it is very
stable.
So, if an atom had six protons, it should also
have______________________________.
Some kinds of atoms have loosely attached electrons.
An atom that loses electrons has more protons than electrons and is
_________________________ charged.
An atom that gains electrons has more negative particles and is
__________________________charged.
A "charged" atom is called an "______________________.”
Vocabulary
Crossword
Across
1. positively charged parts of an atom
6 . negatively charged parts of an atom
. 7 atoms are the building blocks for...
. 8 the number of electrons in atoms determine an element's ___ properties
9. neutrally charged parts of an atom
10 . a chart which lists all of the known elements
Down
2 . protons and neutrons are found in this part of an atom
. 3 type of force that holds the nucleus of an atom together
4 . area of science that studies tiny particles like atoms
5 . the word a'tomos comes from this language
Week: Six
Lesson: One
Topic: Elements and Compounds
Elements
An element is made up of one type of atom only. For example, a piece of pure copper is made up
of only copper atoms. There are 118 known elements on Earth and they are all listed in the
periodic table.
Elements in the Earth’s Crust
The earth is composed of various kinds of elements.
About 98% of the total crust is made up of eight elements - oxygen, silicon, aluminium, iron,
calcium, sodium, potassium, and magnesium.
The rest is constituted by elements like titanium, hydrogen, phosphorous, manganese,
sulphur, carbon, nickel and others.
The elements in the earth’s crust are rarely found exclusive but are usually combined with
other elements to make various substances.
These substances are recognized as minerals.
The pie chart below shows the percentage wise share of each element in both the earth’s
crust and the whole earth.
Pie Chart Showing the Percentage of Elements in the Earth’s Crust
Elements and their symbols
In Science, symbols are used to represent elements and each element from the periodic table has
a symbol. This symbol can be made up of one or two letters but it always starts with a capital
letter. For example, the symbol for nitrogen is N and the symbol for lithium is Li.
Table showing elements and their symbols
Name of the Element Symbol of the Element
Hydrogen H
Helium He
Lithium Li
Beryllium Be
Boron B
Carbon C
Nitrogen N
Oxygen O
Fluorine F
Neon Ne
Sodium Na
Magnesium Mg
Aluminium Al
Silicon Si
Phosphorus P
Sulfur S
Chlorine Cl
Compounds
A Compound is a substance that is made up of two or more atoms of different elements
chemically joined (or bonded) together. For example, carbon dioxide gas (CO2) consists of one
carbon atom and two oxygen atoms bonded together. Sodium chloride (NaCl) consist of one
sodium atom and one chlorine atom.
Examples of Compounds
Common Household Compounds and their Uses
Can you give the chemical names of at least 5 other household compounds?
References
Elements and Compounds | Introduction to Chemistry (lumenlearning.com)
Earth’s Crust: Elements, Minerals and Rocks | UPSC STUDY SHARING (wordpress.com)
118 Elements and Their Symbols and Atomic Numbers - BYJU’S
Week: Six
Lesson: One
Worksheet: Elements and Compounds
Circle the correct response in the questions below.
1. The nucleus of an atom consists of
A. positive and negative charges
B. protons and neutrons
C. negative charges alone
D. neurons and electrons
2. Which of the following is NOT an element?
A. Hydrochloric acid
B. Calcium
C. Iron
D. Argon
3. The molecule C6 H12O6 is made up of
A. 6 carbons, 12 hydrogen and 6 oxygen atoms
B. 1 carbon, 1 hydrogen and 1 oxygen atom
C. 12 carbons, 12 hydrogens and 12 oxygen atom
D. 12 carbons, 6 hydrogen and 12 oxygen atoms
4. Which of the following depicts a molecular compound?
A B
C D
5. Which scientist describes an atom as a mass of positive charges containing negative
electrons?
A. Dalton
B. Rutherford
C. Thompson
D. Bohr
6. In which year was the atom shown below discovered
A. 1807
B. 1903
C. 1913
D. 1911
7. Which two elements are likely to share electron
A. sodium and chlorine
B. hydrogen and oxygen
C. magnesium and chlorine
D. aluminium and oxygen
Fill in the blanks with words from the box.
atoms carbon electrons element
mass negative neutrons nucleus
positive properties protons space
A model of an atom showing a
nucleus in the center and electrons
moving around the nucleus.
Matter is anything that has _________________ and takes up
_________________. An _________________ is matter that cannot
be broken down into anything simpler by a chemical reaction.
Copper, oxygen, and _________________ are examples of
elements.
If you kept trying to divide an element into smaller and smaller pieces eventually you would
come to a piece of that element that cannot be divided further. These smallest indivisible pieces
of elements are called _________________. An atom is the smallest unit of an element that
keeps the _________________ of the element.
All atoms of every element are composed of smaller particles. The center of each atom, called
the _________________, contains _________________ and _________________. Moving
around the atom on the outside of the nucleus there are _________________. Protons have a
_________________ charge whereas electrons have a _________________ charge. Neutrons
have no charge at all.
Week: Six
Lesson: Two
Topic: Formation of Compounds
Formation of Compounds
Compounds can be formed by sharing electrons, or by gaining and losing electrons.
Formation of Molecular compounds
These compounds are formed by sharing the electrons in the last shell of their atoms. The atoms
involved may be from the same element or from two different elements that are both non-metals
(hydrogen, oxygen, nitrogen and chlorine). When these elements combine they form molecules.
Example:
Here we see the two hydrogen atoms sharing their one electron in their last shell with one
oxygen atom. The oxygen is sharing one electron with each hydrogen atom.
Examples of molecular compounds are:
Water
Ammonia
Oxygen
Nitrogen
Chloroform
Formation of Ionic compounds
These compounds are formed by gaining and losing the electrons in their last shell of their
atoms. This type of compound is formed between an element that is a metal and one that is a
non-metal. Example: sodium (metal) and chlorine (non-metal).
Example
The diagram shows clearly that sodium with one electron in its last shell is losing that electron to
chlorine which has seven electrons in its last shell. Every atom wants to be electrically neutral or
stable by losing and gaining the electrons they are able to achieve this state. The compound
formed is sodium chloride (always put the name of the metal first).
Examples of Ionic compounds
Sodium chloride
Copper sulphate
Aluminium oxide
Iron oxide
Potassium nitrate
Chemical Formula of Compounds
A compound may be represented by a chemical formula.
A chemical formula shows the elements in the compound and the ratio of atoms.
A formula is a shorthand way of showing the elements in a compound. The formula for sodium
chloride is NaCl. This compound must be made up of two elements as there are two capital
letters present in the formula. By consulting the Periodic Table, you can discover that this
compound is made up of one sodium atom (Na) and one chlorine atom (Cl). Another compound,
potassium oxide has the formula K2O. It consists of potassium atoms (symbol K) and one oxygen
atom (symbol O). Apart from the elements present in a compound, the formula also indicates
how much of each atom is in the compound. It, therefore, means that this compound has two (2)
potassium (K) atoms.
When writing symbols of elements be sure to take extra care, paying close attention to whether
the letters should be in upper or lower case.
For example, writing CO instead of Co completely changes the substance you are talking about.
CO is the formula for the compound carbon monoxide (a deadly, colourless gas), whereas Co is
the symbol for the element Cobalt (a magnetic metal found in the Earth’s crust).
Combining more than one element
When magnesium ribbon is burnt, white ash called magnesium oxide is produced. To obtain
magnesium oxide, magnesium must combine with oxygen. Thus the wore equation is
magnesium + oxygen Magnesium oxide
Magnesium + Chlorine Magnesium chloride
Hydrogen + Oxygen Water
Calcium + Oxygen Calcium oxide
Examples of compounds and their chemical formulae
- carbon dioxide (CO2)
- sodium chloride (NaCl)
- magnesium chloride (MgCl2)
- potassium nitrate (KNO3)
- sodium sulphate (Na2SO4)
Making compounds in Industries
Many compounds are made by industries and are very beneficial to our everyday life. Here are
some compounds that are made by industries.
Sugar
Sugar cane (sucrose – C6H22O11) is manufactured from the juice of sugar cane. The juice is
extracted from the cane, then the chemical, calcium hydroxide, is added to the juice and the
mixture is boiled. This chemical causes the impurities to collect in such a way that it is easily
removed (clarified). The mixture is then filtered. The clean syrup left is then boiled in a special
way until a mixture of crystals and molasses are formed. The mixture is cooled and the molasses
is separated from the crystal by the method of centrifugation. Hence the compound sugar which
is sucrose – C6H22O11 is formed in this way.
Rum
Rum is mainly ethanol (C2H5OH) or it is also called ethyl alcohol. Rum is made by the process
of fermentation followed by distillation. When molasses or sugarcane juice is allowed to
ferment, rum is produced. After some time, it is distilled. This process is carried out in stills and
the rum is stored in casks to mature. This adds flavor to the rum. Rum is another a compound
that is made by industries. Wines and beers undergo a similar process and they too form
compounds.
Ammonia
This gas (NH3) is manufactured from the elements of nitrogen and hydrogen. Ammonia in turn is
used in the production of nitric acid, fertilizers, nylon, and other man-made fibers. Nitric acid is
used to make explosives, dyes, fertilizers, and many other chemicals.
References
Blackman, S., Bernard, M., Dalgety, F., & Sadoo, d. S. (2000). Science in Daily Life Bk. 2.
Georgetown, Guyana: Ministry of Education, Guyana.
https://www.britannica.com/science/periodic-table
https://courses.lumenlearning.com/introchem/chapter/elements-and-compounds/
https://www.britannica.com/science/chemical-compound
Week: Six
Lesson: Two
Worksheet: Formation of Compounds
Circle the correct response for the questions below.
1. How many atoms are there in total in a molecule of sulphur trioxide, SO3?
A. 1
B. 2
C. 3
D. 4
2. Which of these contains two carbon atoms and six hydrogen atoms?
A. CH4
B. C2H6
C. C2H4
D. none of the above
3. The compound sodium chloride is made from
A. Na and Cl
B. So and Cl
C. S and Cl
D. Na and C
4. Potassium nitrate is made up of ……….. different atoms
A. 2
B. 4
C. 5
D. 6
5. The symbol for potassium is
A. P
B. K
C. PO
D. Po
6. The element found in sodium nitrate are:
A. Na and O
B. So and O
C. Na, N and O
D. So, N and O
Name the following ionic compounds:
1) NaBr __________________________________________
2) CaO __________________________________________
3) Li2S __________________________________________
4) MgBr2 _________________________________________________
Write the formulas for the following ionic compounds:
1. potassium iodide __________________________________________
2. magnesium oxide __________________________________________
3. aluminum chloride __________________________________________
4. calcium chloride __________________________________________
5. aluminum oxide __________________________________________
Write the names of the following molecular compounds:
1. N2S __________________________________________
2. BF3 __________________________________________
3. CO __________________________________________
4. SiO2 __________________________________________
5. NH3 __________________________________________
6. NO2 __________________________________________
Write the formulas of the following molecular compounds:
1. methane __________________________________________
2. sulfur dibromide __________________________________________
3. carbon dioxide __________________________________________
4. oxygen difluoride __________________________________________
5. carbon monoxide __________________________________________
Week: Six
Lesson: Three
Topic: Mixtures and Separation Methods
What is a Mixture?
Mixtures are made up of two or more substances that are not chemically combined.
General Properties of Mixtures
The properties of mixtures are listed below.
The components of a mixture each keep their original properties.
The separation of components can be easily done by physical means.
The proportion of the components varies.
Examples of Mixtures
Crude oil: A mixture of organic compounds (mainly hydrocarbons)
Seawater: A mixture of various salt and water.
Air: a mixture of various gases like oxygen, carbon dioxide, nitrogen, argon, neon, etc.
Ink: A mixture of coloured dyes.
Gun powder: A mixture of sulfur, potassium nitrate and carbon.
Types of Mixtures
Heterogeneous Mixture
Heterogeneous mixtures possess different properties and compositions in various parts i.e. the
particles are not uniformly distributed throughout the mixture. A mixture of sand mixed and water
is an example of a heterogeneous mixture. If you mix sand and water you will see that while you
are stirring the mixture it appears to be mixing. However, when stirring stops, all the sand will
settle at the bottom of the container.
Examples – a mixture of oil and water
Homogeneous Mixture
Homogeneous mixtures possess the same properties and combinations throughout their mass.
Sugar mixed with water is the most common example of a homogeneous mixture. The sugar is
distributed evenly throughout the mixture.
Examples – alloys, salt in water, alcohol in water
Methods of Separating Mixtures
Separation
Technique
Meaning Diagram
Chromatography A separation
technique
used to
separate
colours and
pigments.
Distillation The
evaporation
and
subsequent
collection of a
liquid by
condensation
as a means of
purification
Fractional
Distillation
components in
a chemical
mixture
separated into
different parts
due to their
different
boiling points
Separating funnel A method
used to
separate
liquids of
different
densities
Sedimentation the deposition
or production
of sediment
Filtration Filtration is
the separation
of substances
based on their
different
physical and
chemical
qualities.
References
What is a Mixture? - Definition, Properties, Examples & Types with Videos (byjus.com)
Chemistry for Kids: Chemical Mixtures (ducksters.com)
Methods of Separation - Learn Various Separation Techniques With Examples (byjus.com)
Chemistry for Kids: Separating Mixtures (ducksters.com)
Week: Six
Lesson: Three
Worksheet: Mixtures and Separation Methods
1. Classify each of the following as elements (E), compounds (C), or Mixtures (M). Write
the letter X if it is none of these.
__Diamond(C)
__Sugar (C6H12O6)
__Milk
__Air
__Sulfuric Acid (H2SO4)
__Gasoline
__Krypton (K)
__Bismuth(Bi)
__Uranium (U)
__Water(H2O)
__Alcohol (CH3OH)
__Pail of Garbage
___Ammonia(NH3)
___Salt (NaCl)
___Energy
___Wood
___Bronze ___Ink
__Dry Ice (CO2)
__Baking Soda (NaHCO3)
__Titanium (Ti)
__Iron (Fe)
__Popcorn
__Gold (Au)
__Electricity
__A dog
__Concrete
2. Match each diagram with its correct description. Diagrams will be used once.
A B C D E
__ Pure Element – only one type of atom present.
__ Mixture of two elements – two types of uncombined atoms present.
__ Pure compound – only one type of compound present.
__ Mixture of two compounds – two types of compounds present.
__ Mixture of a compound and an element.
3. Read each description and determine whether it is a pure substance or mixture. Then
further classify the matter (element, compound, homogeneous mixture, heterogeneous
mixture)
Description Pure Substance
or Mixture?
Classification?
1. Chocolate syrup is added to milk and stirred
2. Copper metal (used to make wires)
3. Sand is added to water
4. Distilled water
5. Tap water
6. Diamond
7. Table sugar
8. Table sugar added to a cup of coffee and
stirred
9. Kool-Aid is added to water
10. Coca-Cola
11. Helium gas (used to inflate a balloon)
12. Mercury metal (used in old thermometers)
13. Hydrogen gas (an explosive gas)
14. Trail mix (peanuts, pretzels and m&m's)
15. The air we breathe
Week: Seven
Lesson: One
Topic: Electrolysis
Content
In our previous lesson we looked at how compounds are made. Today we will look at how
compounds are broken down to produce the elements from which they came.
Scientists have learned how to use the power of electricity to split elements and compounds. The
term 'electrolysis' is easy to remember if you break the word down into its parts. The first part of
the word, electro, refers to electric. The second part of the word, lysis, is a scientist's way of saying
that something is splitting. So, electrolysis is 'electric splitting.'
Electrolysis is the process where an electric current is passed through a liquid that conducts
electricity.
In order for electrolysis to be possible the following must me present:
electrodes
an electrolyte
power source
conducting wires
Electrolyte: This is a liquid that conducts electricity. A liquid will only conduct electricity if it
contains ions.
Electrode: This is a solid electric conductor that carries electric current. Electrodes are good
electric conductors. In electrolysis, there are usually two electrodes – the anode and the cathode.
An anode is the positively charged
electrode.
A cathode is the negatively charged
electrode.
Power Supply
The process of Electrolysis
The process is carried out in an electrolytic cell, an apparatus consisting of positive and negative
electrodes held apart and dipped into a solution containing positively and negatively charged
ions. Electric current (i.e., electrons) enters through the negatively charged electrode (cathode);
components of the solution travel to this electrode, combine with the electrons, and are
transformed. The products can be neutral elements or new molecules. Components of the
solution also travel to the other electrode (anode), give up their electrons, and are transformed to
neutral elements or new molecules.
E
source: (Free Exam Academy, 2018)
Importance of Electrolysis in Industry
The process of electrolysis is used to extract and purify metals in industries. Example -
Electrolysis plays an important role in the Bauxite Industry. Bauxite is a red - brown rock found
in some parts of Guyana. Bauxite is impure aluminum oxide. It was difficult for the aluminum to
be separated from aluminum oxide until the method of electrolyzing was devised during the 19th
century.
How is Aluminium made?
The aluminum production process can be broken down into three stages.
1. Bauxite which contain aluminum is extracted from the ground.
2. Bauxite is processed into alumina or aluminium oxide.
3. Pure aluminium is produced using electrolytic reduction. Here the aluminium oxide is
broken down into its components (aluminium and oxygen) using electric current.
Production of Pure Aluminium
The impure aluminium oxide is boiled with sodium hydroxide solution in order to purify
it.
The impurity removed is brown iron oxide. The pure alumina is a white powder. Alumina
is insoluble in water and has a very high melting point.
The alumina is dissolved in molten cryolite at a temperature of about 9000C in iron tanks.
A very high current, about 10 000A (A- ampere), is used.
Aluminium and oxygen are produced. The aluminum runs off from the bottom of the tank
and is cast into bars.
Electrolytic cell for aluminium extraction
source: (GSCE OCR 21st Century, n.d)
Reference
Blackman, S., Bernard, M., Dalgety, F., & Sadoo, d. S. (2000). Science in Daily Life Bk. 2.
Georgetown, Guyana: Ministry of Education, Guyana.
https://www.bbc.co.uk/bitesize/guides/zpxn82p/revision/2
https://www.britannica.com/science/electrolysis
How to Define Anode and Cathode (thoughtco.com)
Week: Seven
Lesson: One
Worksheet: Electrolysis
Circle the correct answer for each question.
1. Which statement correctly describes the 2 electrodes?
A. The anode is negative and the cathode is positive
B. The anode and cathode are both positive
C. The anode is positive and the cathode is negative
D. The anode and cathode are both negative.
2. What is the name given to the solution that is being electrolysed?
A. Salt solution
B. Electric solution
C. Mineral solution
D. Electrolyte
3. What happens at the positive electrode?
A. Positive non-metal ions are attracted
B. Positive metal ions are attracted
C. Negative non-metal ions are attracted
D. Negative metal ions are attracted
4. The process of electrolysis is carried out in a ……………, an apparatus consisting of
positive and negative electrodes
A. electrode
B. anode
C. electrolyte
D. electrolytic cell
5. Covalent compounds cannot act as electrolytes because
A. they are neutral
B. they contain positive atoms only
C. they contain negative atoms only
D. they contain both positive and negative atoms
6. Electrolysis is used to
A. extract and purify metals
B. purify liquids
C. extract liquids from solids
D. purify solids and liquids
7. In electrolysis, a very high current of …………….. A is passed
A. 40 000
B. 30 000
C. 20 000
D. 10 000
8. Positive ions are called
A. cations
B. anions
C. anode
D. cathode
9. …………………. can be used to remove the impurities from aluminium oxide
A. water
B. sodium hydroxide
C. hydrochloric acid
D. chlorine
10. Which of the following is true about Alumina
A. it is insoluble in water and has high melting point
B. it is soluble in water and had a low meting point
C. it is insoluble in water and has a low melting point
D. it is soluble in water with a high melting point
Electrolysis
1
2 3
4
5 6 7
8 9
10
11 12
13
14
15
Across
2. The negative electrode.
6. What type of current must be used for
electroysis?
8. A negatively charged ion.
12. What state must compounds be in for
electrolysis? Aqueous or _______________.
13. What happens to compounds during
electrolysis?
14. The gain of electrons.
Down
1. What type of compounds can split up by
electrolysis?
3. What type of element usually forms
positively charged ions?
4. What charge do the ions have that move
towards the positive electrode during
electrolysis?
5. The loss of electrons.
15. The positive electrode. 7. What charge do the ions have that move
towards the negative electrode during
electrolysis?
9. A positively charged ion.
10. Do negative ions lose or gain electrons when
they get to the electrode in order to form neutral
atoms?
11. Do positive ions lose or gain electrons when
they get to the electrode in order to form neutral
atoms?
Week: Seven
Lesson: Two
Topic: Electrolysis - Experiment
Content
In our previous lesson we looked at how electricity can be used to purify substances. Now let us
determine which electrolytes will best conduct electricity.
Pure water is not a good conductor of electricity, so for this experiment baking soda will be
added to make the solution an electrolyte.
Title: Electrolysis
Aim: to determine which electrolyte conducts electricity the best.
Diagram
Materials
Distilled water
Tap water
2 silver-colored thumb tacks
9V battery
Small, clear plastic container cup
2 test tubes
Stopwatch
Baking soda
Table salt
Lemon
Dishwashing detergent
Procedure
1. Half fill the cup with water and then stir in a ¼ teaspoon of baking soda.
2. Sharpen both end of both pencils with a sharpener – these will be our terminals.
3. Bore two holes in the lid of the plastic cup about 3-4cm apart.
4. Push the pencils through the doles so that they are halfway down the lid.
5. Place the lid back on the cup and make sure the pencils are submerged in the water.
6. Connect crocodile clips (wires) to each of the exposed ends of the pencils.
7. Connect these crocodile clips to the ends of the battery terminal. Record your
information in a table.
8. Discard the solution, and repeat the procedure with a different combination of
substances.
Distilled water and lemon juice
Distilled water and table salt
Distilled water and dish detergent
Distilled water (no additive)
Tap water
Questions
1. Does distilled water conduct electricity on its own? Explain your answer.
2. Does tap water conduct electricity? If so, why?
3. Why was baking soda, lemon juice or table salt added to the distilled water.
4. Which experiment was the control?
5. Name the substances produced from this experiment.
References
Part water with a simple electrolysis experiment - Coffee Cup Science
Electrolysis of Water - A Simple Experiment - Eva Varga
Part water with a simple electrolysis experiment - Coffee Cup Science
Week: Seven
Lesson: Two
Worksheet: Electrolysis - Experiment
Electrolysis word search
J Z R D K E N E R G Y J N O V U T Z X L C Z O D
H F T I X D O T R M K A O C W L P R E X P S W X
I H X B E L E C T R O L Y S I S J I X I Z U N H
O J N B S V W U E C W R N A G K P V O F O F N Y
F S J P Q Z B S V B A R Z P N Y H N R B O X L B
E F A G R U C N I L W G F P U N I P J A D V B J
L E V A Q R O Z T X H O U Y U C K D X K E V L E
E S S I M Q W Q I U M N P U C F L X F T Y O D P
C G E F G A M B S F P D E O P U M N E E V O V U
T O R J J H X G O T I T M G J T A V X R H A K D
R W S V M V B Y P H S P W H A C O O Y T L T X X
I L W Q W F S H N O O L P F N T I R A J O I P T
C J S S N O I T A U Q E F L A H I C W J Y R E B
C U V Z P T Q L N V E A S D Z S E V N F Y N R R
U K Y M K F N D N T Y Z Y D B V D W E B X V E R
R I L Z X F M C Y V P Q N N Z U O W A C E V T A
R T G R T Z C L U G W G E L Y G N E R O B U A F
E G G L U V O W V X E B T J P N A Q O C M M W J
N Z Q T E R X N C P H L A H J X K X O A Q J L I
T D F E T G S P V Y M R V N J F D B F E O D S M
W O V C D A J E A Q U S R G R R S T I W U D E Y
Q U E Y D V I R Q E D O R T C E L E P U F Y W M
Z L L I Q N C I L N U E O F P R R G O B P X G C
E J N A A L Z N L S G G V V Q L M L N B Y N M X
negative positive water energy electrolyte electrode anode cathode
electric current ionic compound electrolysis
Week: Seven
Lesson: Three
Topic: Review
Part 1. We use chemical formulas to represent the number and identities of atoms in molecules.
For each of the chemical formula listed below, provide the name of the compound and the names
of the individual elements present.
Compound Formula Elements
1 CH4
2 C2H5OH
3 CO2
4 CuSO4
5 H2O
6 H2SO4
7 HCL
8 NaCl
9 NaOH
10 NH3
Part 2: In the table below, classify the following materials as elements, compounds or mixtures by
writing E, C or M respectively in the empty boxes.
1
air
11
milk
2
alcohol
12
nail polish
3
blood
13
nitrogen
4
cake batter
14
oxygen
5
carbon dioxide
15
salt water
6
coffee
16
sodium
7
cola
17
soil
8
eggs
18
soup
9
ice cream
19
table salt
10
iron
20
water
Part 3: In the table below, classify the following substances or mixtures as homogeneous or
heterogeneous by placing an X in the appropriate box.
HOMOGENEOUS HETEROGENEOUS
1 alcohol
2 aluminum foil
3 beach sand
4 black liquid coffee
5 cherry vanilla ice cream
6 dirty polluted air
7 flat soda pop
8 iron
9 paint
10 pure clean air
11 salad dressing
12 soil
13 spaghetti sauce
14 sugar
Part 4: Often we wish to separate mixtures into their individual components (e.g., if one is more
valuable or useful on its own) We can do this by using the differences in the physical and
chemical properties of the components. For the mixtures below, describe a method that would
allow us to separate them into their components?
____________________________________________________________________________________
____________________________________________________________________________________
5. A mixture of salt and iron fillings ________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
1 . Sugar and water
2 . Oil and water
3 . Sand and gravel
4 . A mixture of water and alcohol (ethanol)
Part 5:Provide the chemical symbols for the elements listed below.
1 bromine 11 lead
2 calcium 12 magnesium
3 carbon 13 manganese
4 chlorine 14 neon
5 copper 15 nitrogen
6 fluorine 16phosphorus
7 Gold 17 potassium
8 helium 18 silver
9 hydrogen 19 sodium
10 iron 20 sulfur
Provide the name for the element corresponding to the chemical symbols below.
21 Al
22 Au
23 C
24 Ca
25 Cu
26 F
27 Fe
28 H
Week: Eight
Lesson: One
Topic: Indicators and the pH Scale
Content
The nature of a substance, that is, whether it is acidic, basic or neutral can be determined by using
a pH scale or an indicator.
Indicator are substance that give a visible sign, usually by a colour change when it comes into
contact with acidic, basic or neutral substances. Examples of indicators include litmus paper,
phenolphthalein, universal indicator and methyl orange are all indicators that are commonly used
in the laboratory.
1. Universal indicator - is a mixture of coloured compounds, which is used for simple testing
of solutions.
2. Litmus paper - Litmus is a vegetable based dye that was used in schools before the
advent of universal indicator. It has a simple colour scheme, in acids it turns red and in
bases it turns blue. It is usually used in the form of a paper, impregnated with the
litmus dye. This comes in two varieties, the red litmus paper that is used to test for
bases and the blue litmus paper that is used to test for acids.
3. Phenolphthalein is an organic indicator. It is red in bases and colourless in acids.
4. Methyl orange is an acid base indicator that turns red in acidic solution and yellow in
base.
The pH Scale
This scale is used to
compare the strengths of
acids and bases using a
range of number from 0-
14. A pH value between
0 – 6 indicates that a substance is acidic while a range between 8-14 indicates that the
substance is basic. A pH value of 7 denotes a neutral substance. Water is a good example of a
neutral substance.
Comparing the pH of substances
Reference
Blackman, S., Bernard, M., Dalgety, F., & Sadoo, d. S. (2000). Science in Daily Life Bk. 2.
Georgetown, Guyana: Ministry of Education, Guyana.
http://chemistry.elmhurst.edu/vchembook/184ph.html
https://www.bbc.co.uk/bitesize/guides/z89jq6f/revision/1
Week: Eight
Lesson: One
Topic: Indicators - pH Scale
Circle the correct response for each question below.
1. Acids are found on the pH scale between which numbers?
A. 0-7
B. 7
C. 7-14
D. 19-42
2. Which is the stronger acid?
A. pH 1
B. pH 4
C. pH 8
D. pH 13
3. According to the pH range which substance is more acidic than lemon juice
A. cabbage
B. milk
C. hydrochloric acid
D. lye
4. According the pH scale, which of the
following is alkaline
A. water
B. milk of magnesia
C. lemon juice
D. hydrochloric acid
5. The pH scale measures ____ and
____
A. acidity only
B. the temperature
C. acidity and alkalinity
D. alkalinity only
6. A solution with a pH of 7 is________
A. neutral
B. acidic
C. alkaline
D. acidic as well as neutral
7. A solution with a pH of 10 is mixed
with a solution with a pH of 4. What
would the pH of the mixture most
likely be?
A. 10
B. 4
C. 40
D. 7
8. The pH scale ranges from
A. 7 to 10
B. 1 to 14
C. 0 to 14
D. 7 to 10
9. All of the following can be used as
indictors EXCEPT
A. Litmus
B. phenolphthalein
C. methyl orange
D. orange litmus
10. Our stomach is likely to have a pH of
A. 1-2
B. 4-5
C. 6-7
D. 8-9
Find the words listed below in the word search
S N E U T R A L I Q P X X J M W F S X Y N W N M
U Q W F K X V Z B O A E N F X D X O E M I C D O
L A H B Z F Y I B L Z W P H P F B S V F T B N K
P D I R T M S O W V G L F U R E D Y L M R M R T
H J K T S F O X G M W L L H V X B C E G I J M O
U F R K R K M R A C I D I T Y C V G Z P C B V U
R M J J D F B S K M K B M M S O N L W R S L M J
I H S V Z G C N I U E E B D B Z P K Y G Y U O W
C E Y D F R U V U U V E L K W N B J C S U E E D
D W N N K G H A B Z A A Z V K E V T Q U Q S W W
C E T X B A U Y M M M K R Z R S A L K A L I N E
N A S O D I U M H Y D R O X I D E Q H W X Z T D
I K J Y D H E O H K V C H P G U K H S X J R K T
V B Y S D U S L H L H B S M Z C G H D F E A G Y
A A V T Q Y F I M E R L W A C I D A H S W V N O
Y S T R X F T T L B S G R E E N L Y C M C S S A
P E I E P G C M A V K E U S O P A Z E J B Q V S
C F T N B C W U H K D N F J Y V Y U O W C N R R
S C R G O D K S F W D Z Z R W M Y F A C T X G U
I K A T I H S P Q C L Y U P M W E A K A C I D O
K M T H C T E A S V P T E D C S T R O N G J A Z
H M E D L S S P Z U N K H Y D R O C H L O R I C
M O K J R H U E L K A T P P A W W I D Q H I K S
G H U N I V E R S A L I N D I C A T O R L C Q U
Acid Acidity Alkaline Blue Green Hydrochloric Litmus paper
Neutral Nitric Red Sodium hydroxide Strength Strong Sulphuric
Titrate Universal Indicator Weak acid Weak base
Solve the crossword using the clues below.
1
2
3
4
5 6
7
8
9
10
Across
4. The paper to test acids or alkilis
5. Shampoo is a
7. What is mixed with oxygen to make air
8. Iron+Oxygen=
9. What type of acid is in fizzy drinks
10. Calcium+oxygen=
Down
1. When it burns your skin
2. The scale to test if they are strong or weak
acids and alkalis
3. What bleach is
6. The acid found in lemons and oranges
Week: Eight
Lesson: Two
Topic: Making Indicators
Content
In the previous lesson we looked at indicators found in a science laboratory and how they are
used to test the acidity, basicity or neutrality of a substance.
Today we will learn how to make our own indicators and use them to test the pH of substances in
and around the home. In order to do this activity, we will use red cabbage.
Red Cabbage Indicator
Red cabbage juice contains a natural pH indicator that changes colors according to the acidity of
the solution. Red cabbage juice indicators are easy to make, exhibit a wide range of colors, and
can be used to make your own pH paper strips.
Materials You Will Need
Red cabbage
Blender or knife
Boiling water
Strainer or Colander
2 small glass containers
Household ammonia (NH3)
Baking soda
Baking powder
Lemon juice
Vinegar
Antacids
Soda water
Cherries
Bright bowl
Distilled water
Tap water
Squeezy or any other soap solution
Procedure
1. Chop the cabbage into small pieces until you have about 2 cups of chopped cabbage.
Place the cabbage in a large beaker or other glass container and add boiling water to
cover the cabbage. Allow at least 10 minutes for the color to leach out of the cabbage.
Alternatively, you can place about 2 cups of cabbage in a blender, cover it with boiling
water, and blend it.
2. Filter out the plant material to obtain a red-purple-bluish colored liquid. This liquid is at
about pH 7. The exact color you get depends on the pH of the water.
3. Pour about 50–100 mL of your red cabbage indicator into each 250 mL beaker.
4. Add various household solutions to your indicator until it changes color. Use separate
containers for each household solution—you don't want to mix chemicals that don't go
well together.
5. Record our observations in a table.
Red Cabbage pH Indicator Colors
pH 2 4 6 8 10 12
Color Red Purple Violet Blue Blue-Green Greenish Yellow
Questions
1. What is the name of the pigment in red cabbage that causes it to work as an
indicator?
2. Name 2 other foods in which this substance is found.
3. Why does the colour of the cabbage juice change?
4. Make a list of 3 safety precautions that you should take when carrying out this
experiment.
5. Write the steps you would take to make red cabbage indicator.
References
How to Make a Red Cabbage pH Indicator (thoughtco.com)
Make Your Own Indicators | Carolina.com
Week: Eight
Lesson: Three
Topic: Acids
Content
The word acid comes from the Latin words acidus or acere, which mean "sour,". This sourness of
acids is caused by the hydrogen ions they contain. An acid is a substance with many hydrogen
ions in it.
Some Properties of Acids
source: (CK-12 Foundation, 2020)
Classification of Acids
Acids can be classified based on their source or origin. Acids are classified into two groups based on
their source of origin - Organic acid and Mineral acid (Inorganic acid)
Inorganic acids (mineral) are manufactured and are widely used in industrial processes.
Examples of inorganic acids are sulphuric, hydrochloric, nitric and phosphoric acid. Organic
acids are compounds found in vinegar, fruit, sour milk and other natural substances.
Organic acids contain carbon atoms and are not strong. Ascorbic acid or vitamin C which is found
in limes, oranges and tomatoes prevent us from having a disease called scurvy. Carbonic acid is
another example. Amino acids are another group of acids that contain nitrogen. They play an
important part in the structure of protein, since they are the building blocks of proteins.
What is the importance of acid?
Acids play significant roles within the human body. The presence of hydrochloric acid in the
stomach helps digestion by breaking down large and complex food molecules. Amino acids are
required for protein synthesis needed to grow and repair body tissues.
Table showing some common acids and where they can be found
Acids Where found
Acetic acid (Ethanoic acid) vinegar
Ascorbic acid (vitamin c) Fruits e.g cherries, citrus fruits
Citric acid Citrus fruits e,g lemons, limes, oranges
Lactic acid Sour milk
Tartaric acid Fruits
Tannic acid Tea leaves
Reference
Blackman, S., Bernard, M., Dalgety, F., & Sadoo, d. S. (2000). Science in Daily Life Bk. 2.
Georgetown, Guyana: Ministry of Education, Guyana.
https://byjus.com/chemistry/acids-and-bases/
https://www.britannica.com/science/acid
http://chemed.chem.purdue.edu/genchem/topicreview/bp/ch11/acidbase.php
Week: Eight
Lesson: Three
Topic: Review
1. Which of the following word pairs correctly completes the sentence below?
_______ are corrosive substances characterized as having a strong smell, a sour taste, and
a _______.
A. Acids; pH less than 7
B. Acids; pH greater than 7
C. Bases; pH greater than 7
D. Bases; pH less than 7
2. The esophagus is the tube that connects the mouth to the stomach. Heartburn occurs when
some of the stomach juices flow backwards up the esophagus. To help relieve heartburn, a
person should take medicine that is
A. neutral
B. basic
C. acidic or basic.
D. acidic
3. If an acid is combined with a base of equal strength, the result will most likely be
A. a neutral solution.
B. a stronger acid.
C. impossible to tell without testing the pH.
D. a stronger base
4. Holly has an unknown substance in a beaker. She wants to determine the relative pH of the
unknown substance. She places a piece of blue litmus paper into the substance, and the
litmus paper stays blue. The substance in the beaker
A. is a base.
B. has a neutral pH.
C. is an acid.
D. does not have a pH.
5. Which of the following statements is correct?
A. Blue litmus paper turns red when placed in an acid
B. Red litmus paper turns blue when placed in an acid
C. Blue litmus paper stays blue when placed in an acid.
D. Red litmus paper stays red when placed in a base.
6. Which of the following is an acid?
A. shampoo
B. baking soda
C. orange juice
D. water
7. The pH of a solution is tested, and it is found to be an acidic solution. Of the following
choices, what could the pH have been?
A. 14
B. 7
C. 8
D. 5
8. When using pH paper, the pH of a solution can be determined by looking at the _______ of
the paper.
A. texture
B. colour
C. length
D. mass
9. Which of the following is not a property of a substance that has a pH of 4
A. sour taste
B. turns blue litmus red
C. turns red litmus blue
D. produces H+ ions in water
10. The acid found is sour milk is called
A. citric acid
B. lactic acid
C. ascetic acid
D. tannic acid
11. Which statement correctly describes a solution with a pH value of 10?
a. It would turn litmus red.
b. It would turn methyl orange-red.
c. It would turn thymol blue yellow.
d. It would turn phenolphthalein pink.
12. Which of the following indicators would be most useful to distinguish between soda, which
has a pH of 2, and a sample of acid rain, which has a pH of 5?
a. bromthymol blue
b. methyl orange
c. litmus
d. phenolphthalein
13. A lake has a pH of 3.0, where the rates of mortality for adult fish are steadily increasing over
time. How would a sample of water from this lake affect bromothymol blue?
a. It would turn the indicator blue.
b. It would turn the indicator red.
c. It would turn the indicator yellow.
d. It would turn the indicator pink.
14. What is the color of methyl orange for a sample of potassium hydroxide, KOH?
a. It is red.
b. It is orange.
c. It is yellow.
d. It cannot be determined, based on the information given.
15. Phenolphthalein helps to provide the endpoint of titration with a reasonable amount of
accuracy.
a. True
b. False
SHOW ANSWER
Week: Nine
Lesson: One
Topic: Chemical Properties and Uses of Acids
Content
Acids react with elements and compounds to form new substances. Some chemical properties of
acids are:
produce heat when dissolved in water
change the colour of indicators.
react with bases and produce salt and water, it is called a neutralization reaction.
react with some metals and produce hydrogen.
React with carbonates to produce salt, water and carbon dioxide
Uses of Acids
Hydrochloric Acid (HCl)
Dilute hydrochloric acid is used in various industries that use heating applications. It is applied to
remove deposits from the inside of the boilers. Hydrochloric acid is also used for cleaning sinks
and sanitary ware.
source: (Knapp, 2020)
Sulphuric Acid (H2SO4)
Sulphuric acid is such an important industrial
chemical that it is called the king of chemicals.
Some of its major uses are as follows:
- Sulphuric acid is used in car batteries.
- It is used in the manufacture of paints,
drugs, dyes, and to produce fertilizers.
Nitric Acid (HNO3)
- It is used by goldsmiths for cleaning gold and silver ornaments.
- It is also used for the production of fertilizers such as ammonium nitrate.
Acetic Acid (CH3COOH)
Acetic acid is used directly to enhance the flavour of food. We commonly know acetic acid as
vinegar.
- It is also used as a cleansing agent in products meant for cleaning windows, floors, utensils,
etc.
- It also helps to remove stains on woodwork such as furniture and carpets.
Acetic acid is used as a preservative in pickles, etc. Most microorganisms cannot live in an acidic
environment. An acidic environment either slows down their activities or can also kill them. This
is why you will find vinegar in many commonly packaged food items such as pickles, sauce,
ketchup, etc.
Table showing the summary uses of some organic and inorganic acids.
Acid Uses
Organic acids
Citric acid 1. As a preservative for food
2. As a flavouring agent
Ascorbic acid (also
called vitamin C) 1. In the treatment of bone marrow and scurvy diseases
Acetic acid 1. Added to pickles to make them sour
Tartaric acid 1. A component of baking powder (baking powder is a mixture of
sodium hydrogen carbonate and tartaric acid)
Inorganic acids
Hydrochloric acid
1. Its presence in the gastric juice helps the digestion of food we
eat.
2. As a bathroom cleaner
3. In the manufacture of polyvinyl chloride (PVC)
Nitric acid
1. Nitric acid present in rainwater forms nitrates in the soil which
are then used by plants to obtain nitrogen.
2. In the manufacture of fertilizers like ammonium nitrate
3. In making explosives like TNT and dynamite
Sulphuric acid
1. In storage batteries
2. In the manufacture of fertilizers, paints and pigments, detergents
and artificial fiber
3. In the manufacture of hydrochloric acid and alum
Phosphoric acid 1. In fertilizer and detergent industries
Boric acid
1. In the manufacture of glass, glazes and enamels, leather, paper,
adhesives and explosives
2. Widely used in detergents
3. As a grain preservative
Reference
Blackman, S., Bernard, M., Dalgety, F., & Sadoo, d. S. (2000). Science in Daily Life Bk. 2.
Georgetown, Guyana: Ministry of Education, Guyana.
https://www.aplustopper.com/uses-of-acids/
https://www.thoughtco.com/definition-of-acid-and-examples-604358
Week: Nine
Lesson: One
Worksheet: Chemical Properties and Uses of Acids
Circle the correct response for the questions.
1. An acid that is used in the manufacture of fertilizers is
A. nitric acid
B. hydrochloric acid
C. sulphuric acid
D. carbonate acid
2. Which acid leads to a deficiency disease?
A. nitric acid
B. hydrochloric acid
C. sulphuric acid
D. citric acid
3. The formula for sulphuric acid is
A. HSO4
B. H2SO4
C. S2HO4
D. HSO
4. One acid that is used in the manufacture of paints is
A. nitric acid
B. hydrochloric acid
C. sulphuric acid
D. citric acid
5. Acetic acid is commonly known as
A. hydrochloric acid
B. nitric acid
C. vinegar
D. citric acid
6. All of the following are uses of acetic acid EXCEPT
A. enhance flavor of food
B. cleaning agent
C. preservative
D. breaking down food in the stomach
7. Which of the following does not contain citric acid?
A. lime, lemons, cherries
B. lime, lemon, pumpkin
C. cherries, grapefruit, oranges
D. tangerines, oranges, cherries
8. Which acid is used in the manufacture of glass and paper?
A. hydrochloric acid
B. boric acid
C. sulphuric acid
D. citric acid
9. All of the following can be used as preservatives EXCEPT
A. nitric acid
B. boric acid
C. acetic acid
D. citric acid
10. Which acid is used to break down our food?
A. hydrochloric acid
B. boric acid
C. sulphuric acid
D. citric acid
11. Fruit juices, such as orange juice, contain:
A. Boric Acid
B. Citric Acid
C. Sulphuric Acid
D. Nitric Acid
12. A solution reacts with crushed egg-shells to give a gas that turns lime-water milky. The
solution contains:
A. NaCl
B. LiCl
C. HCl
D. KCl
13. Write the formula of the following acids in the space given:
NAME OF THE ACID FORMULA
Carbonic acid
Phosphorus acid
Hydrobromic acid
Nitric acid
Hydrocyanic acid
14. What are the main products of the following reactions?
a) acid/base neutralization = ________________________________________.
b) acid reacting with a metal = _______________________________________.
c) acid reacting with a carbonate salt = ________________________________.
15. What are indicators used for?
________________________________________________________________
________________________________________________________________
_______________________________________________________________.
Week: Nine
Lesson: Two
Topic: Bases
Content
A base is a substance with oxide or hydroxide ions in them. Bases include the oxides, hydroxides
and carbonates of metals.
Alkalis
Alkalis are bases that dissolve in water
Properties of Base
Classification of Bases
Bases can be classified based on their strength. A high amount of hydroxyl ion represents a strong
base and a low amount of base represents a weak base.
Strong base: A base that dissolves completely or almost completely in water is known as a strong
base.
source: (Helmenstine, 2019)
Weak base: A base that does not dissolve completely in water is called a weak base.
Example: ammonium hydroxide
Examples of bases found in the laboratory and their uses
Bases or alkalis form the main ingredient of many household substances. For example,
- Sodium hydroxide is also called caustic soda. It is the main ingredient in the manufacture
of soap and other products for the removal of grease
- Potassium hydroxide is also called caustic potash. It is used for making soap and removing
grease.
- Calcium hydroxide is also called slaked lime. It is used to make plaster and mortar. A
mixture of calcium hydroxide and water (limewater) is used in tanneries to remove hair
from cowhides.
- Calcium oxide is also called lime. It is used by framers to reduce the acid content of the
soil.
Example of Bases in the Home
Comparing the Property of Acids and Base
Reference
Blackman, S., Bernard, M., Dalgety, F., & Sadoo, d. S. (2000). Science in Daily Life Bk. 2.
Georgetown, Guyana: Ministry of Education, Guyana.
https://byjus.com/chemistry/examples-of-bases/
https://www.thoughtco.com/most-common-strong-bases-603649
Introduction to Bases: Classification, Examples with Questions & Videos (toppr.com)
Week: Nine
Lesson: Two
Worksheet: Bases
Circle the correct response to each question.
1. How do acids taste compare to bases
A. Acids are sour
and bases are
bitter
B. Acids are bitter
and bases are
sweet
C. Acids are spicy
and bases are
sour
D. Acids are bitter
and bases are
sour
2. Which of the
following are
characteristics of
bases
(i) very bitter
taste Feels
(ii) slippery to
the touch
(iii) Produces
OH- ions
when
dissolved in
water
(iv) pH less than
7
A. (i) , (ii) and (iii)
only
B. (i) and (ii) only
C. (i) and (iii) only
D. (i) to (iv)
3. Which of the
following statements
is correct?
A. Blue litmus
paper turns red
when placed in a
base.
B. Red litmus paper
turns blue when
placed in a base.
C. Blue litmus
paper stays blue
when placed in
an acid.
D. Red litmus paper
stays red when
placed in a base.
4. Which of the following is not an
example of a base?
A. NaOH
B. KOH
C. Ca(OH)2
D. H2SO4
5. An example of a strong base is
A. ammonia
B. potassium hydroxide
C. silicon dioxide
D. sodium hydride
6. An example of a weak base is
A. ammonia
B. potassium hydroxide
C. silicon dioxide
D. sodium hydride
7. Potassium hydroxide is also called
A. caustic soda
B. lime
C. slaked lime
D. caustic potash
8. A farmer wishes to reduce the acid
content of the soil in his garden.
Which of the following base
should he use
A. sodium hydroxide
B. potassium hydroxide
C. calcium hydroxide
D. calcium oxide
9. Carrie's teacher hands out test
tubes filled with different
chemicals and tells the students to
identify their liquid as an acid,
base, or neutral chemical. Carrie's
test tube contains a clear chemical.
She adds red litmus to her test tube
and gently moves the tube from
side to side. A few moments later,
the chemical in the test tube turns
blue. What type of chemical does
Carrie have?
A. Carrie has a neutral chemical.
B. Carrie has an acidic chemical.
C. Carrie has a basic chemical.
D. The type of chemical Carrie has
cannot be determined.
10. Which of the following is NOT a
base?
A. shampoo
B. baking soda
C. lemon juice
D. bright bowl cleaning agent
11. Which of the following is not a
property of bases?
A. feel slippery on the skin
B. react with salts to form acids
C. taste bitter
D. turn litmus blue
12. . The base often used in soap making is (a) Ca (OH) 2 (b) Mg (OH) 2
(c) NaOH (d) NH3
13. When dissolved in water, there are no visible differences between the substances referred
to as 'acids’ or ‘bases’. However, there are many other physical and chemical properties
that allow us to distinguish an acid from a base. The table below illustrates some of the
differences and similarities between acids and bases.
Indicators Properties of Acids Properties of Bases Properties shown by
Both
Taste
Feel
Reaction with metals
Electrical
conductivity
Action on litmus
pH
Examples
14. Give the name and formula for any four strong bases.
________________________________________________________________
_______________________________________________________________.
15. Five solutions A, B, C, D and E when tested with universal indicator showed pH as 4, 1,
11, 7 and 9, respectively. Which solution is
a. neutral?______________________________________________________.
b. strongly alkaline? ______________________________________________.
Week: Nine
Lesson: Three
Worksheet: Review
Fill in the blank spaces below with the appropriate words.
1. A ________taste is a characteristic property of all acids in aqueous solution.
2. Acids react with some metals to produce ___________ gas.
3. Acids react with bases to produce ___________ and water.
4. Acids turn _________ litmus to _________.
5. Because aqueous acid solutions conduct electricity, they are identified as___________.
6. Bases tend to taste ___________ and feel ___________ to touch.
7. Bases react with ___________ to produce a salt and ________.
8. Bases turn _________ litmus to _________.
9. Like acids, aqueous basic solutions conduct _____________, and are identified as
____________.
10. The _______ scale is a number scale that shows the acidity or alkalinity of a solution in
water.
11. An __________ is a dye that changes colour when pH changes.
12 These are certain substances whose odour (smell) changes in acidic or basic solutions. These
substances are called ______________
13. Farmers use quick lime (calcium oxide) to neutralise _________soils.
14. Our stomach contains _____________, and too much of this causes indigestion. ________
tablets contain bases such as magnesium hydroxide and magnesium carbonate to
__________ the extra acid.
15. Bee stings are ________. They can be ___________using baking powder, which contains
sodium hydrogen carbonate.
Circle the correct response to the questions below.
1. Which of the following is not a property of acids?
(a) feel slippery on the skin (b) react with Zn to form hydrogen gas
(c) taste sour (d)turn blue litmus red
2. Which of the following is not a property of bases?
(a) feel slippery on the skin (b)react with salts to form acids
(c) taste bitter (d)turn litmus blue
3. In general, when an acid and a base are mixed,
(a) a new acid and a salt are formed (b) a new base and a salt are formed
(c) no reaction occurs (d) a salt and water are formed
4. The acid present in sour milk is:
(a) Citric acid (b) Lactic acid
(c) Oxalic acid (d) Tartaric acid
5. The sour taste of lemon is due to
(a) acetic acid (b) ammonia
(c) carbonic acid (d) citric acid
6. The acid used in automobile batteries is
(a) citric acid (b) hydrochloric acid
(c) nitric acid (d) sulphuric acid
7. When a person with excess stomach acid takes an antacid, the pH of the person’s stomach
changes
(a) from a low value to a value nearer 7
(b) from 7 to a much higher value
(c) from a low value to an even lower value
(d) from a high value to a lower value
8. What happens when a solution of an acid is mixed with a solution of a base in a test tube?
(i) The temperature of the solution increases
(ii) The temperature of the solution decreases
(iii) The temperature of the solution remains the same
(iv) Salt formation takes place
(a) (i) only (b) (i) and (iii)
(c) (ii) and (iii) (d) (i) and (iv)
9. Calcium phosphate is present in tooth enamel. Its nature is
(a) basic (b) acidic
(c) neutral (d) amphoteric
10. A sample of soil is mixed with water and allowed to settle. The clear supernatant solution
turns the pH paper yellowish-orange. Which of the following would change the colour of this pH
paper to greenish-blue?
(a) Lemon juice
(b) Vinegar
(c) Common salt
(d) An antacid
Acids, Alkalis and Indicators
2
3
4
5 6
7
8
9
10
Across
4. The paper to test acids or alkalis
5. Shampoo is a
7. What is mixed with oxygen to make air
8. Iron+Oxygen=
9. What type of acid is in fussy drinks
10. Calcium+oxygen=
Down
1. When it burns your skin
2. The scale to test if they are strong or week
acids and alkalis
3. What bleach is
6. The acid found in lemons and oranges
Acid and Bases
1
2 3
4
5
6
7 8
9
10 11
12
Across
4. A solution that is neither acidic nor alkaline,
such as pure water.
7. A numeric scale is used to specify the acidity
or basicity of an aqueous solution.
8. Any substance that gives a visible sign,
usually by a colour change, of the presence or
absence of a threshold concentration of a
chemical species, such as an acid or an alkali in
a solution.
9. A chemical compound that neutralizes or
effervesces with acids and turns litmus blue;
typically.
Down
1. The ion H3O+, consisting of a protonated
water molecule and present in all aqueous acids.
2. Is a chemical reaction in which an acid and a
base react quantitatively with each other.
3. A solution that resists changes in pH when
acid or alkali is added to it. Buffers typically
involve a weak acid or alkali together with one
of its salts.
5. A molecule or other entity that can donate a
proton or accept an electron pair in reactions.
6. A measure of acidity or alkalinity of water-
soluble substances.
10. Are substances that, in aqueous solution, are
slippery to the touch, taste bitter, change the
color of indicators.
11. Any chemical compound formed from the
reaction of an acid with a base, with all or part
of the hydrogen of the acid replaced by a metal
or other cation.
12. The monovalent anion OH− consisting of
one atom of hydrogen and one of oxygen.
Week: Ten
Lesson: One
Topic: Neutralization
Content
A neutralization reaction can be defined as a chemical reaction in which an acid and base react
together to form a salt and water as products. A salt is an ionic compound composed of a cation
from a base and an anion from an acid.
Examples of Acids ad Bases
Below is an example of the reaction between solutions of hydrochloric acid and sodium hydroxide.
The overall equation for this reaction is:
Examples of other Acid – Base reactions
How to name the salt formed in a neutralization reaction
source: (KS4 Chemistry Chemical Reactions, n.d)
Remember
Reference
https://courses.lumenlearning.com/cheminter/chapter/neutralization-reaction-and-net-ionic-
equations-for-neutralization-reactions/
Neutralisation. - ppt download (slideplayer.com)
Week: Ten
Lesson: One
Worksheet: Neutralization
Circle the correct response to each question.
1. A neutralization reaction will always produce.
A. water & salt
B. water
C. salt
D. water & carbon
2. NaCl is a/an ...
A. acid
B. base
C. salt
D. water
3. What are the products of the following reaction?
A. H20 and NaOH
B. H2O and Na2SO4
C. H2O only
D. H2O and H2SO4
4. A salt is composed of
A. a cation from a base and an anion from an acid.
B. a cation from an acid and an anion from a base
C. cation only
D. anion only
5. What are the products of the neutralization reaction between HCl and LiOH
A. H2O
B. H3O+ and OH
C. LiCl
D. H2O and LiCl
6. A salt is an ionic compound that is
A. an acid
B. a base
C. both acid and base
D. neither an acid nor a base
7. The chemical formula for potassium
hydroxide is
A. POH
B. KOH
C. PHO
D. KHO
8. Our stomach contains hydrochloric acid. To relieve indigestion of food what should we
intake?
A. water
B. hydrochloric acid
C. milk of magnesia
D. orange juice
9. The neutralisation reaction between hydrochloric acid and sodium hydroxide
can be written as
A. Hydrochloric acid + Sodium hydroxide → Sodium chloride + Water
B. Hydrochloric acid +Sodium hydroxide → Potassium chloride + Water
C. Hydrochloric acid + Sodium hydroxide → calcium chloride + carbonhydroxide
D. Sodium hydroxide + Water → Sodium chloride + Hydrochloric acid
10. To produce potassium chloride by the reaction
illustrated you need.
A. sodium hydroxide + hydrochloric
acid
B. potassium hydroxide +
hydrochloric acid
C. sodium chloride + potassium
hydroxide
D. potassium sulfate +
hydrochloric acid
Week: Ten
Lesson: Two
Topic: Identifying Gases
Content
Identifying Hydrogen - Burning splint test
A splint is lit and held near the opening of the tube, then the stopper is removed to expose the
splint to the gas. If the gas is flammable, the mixture ignites. This test is most commonly used to
identify hydrogen, which extinguishes with a distinctive 'squeaky pop' sound. Hydrogen is easily
ignited, as it is flammable over a wide range of concentrations in air, making this test quite robust.
If the gas is non-flammable, the burning splint will be extinguished.
source : ( Good Science, n.d)
Identifying Carbon Dioxide
Carbon dioxide reacts with calcium hydroxide (lime water) solution to produce a white precipitate
(solid) of calcium carbonate. Limewater is a solution of calcium hydroxide. If carbon dioxide is
bubbled through limewater, the limewater turns milky or cloudy white.
source: (GCSE OCR Gateway, n.d)
Identifying Oxygen
Oxygen supports combustion so a good method of testing for oxygen is to take a glowing splint
and place it in a sample of gas. If it re-ignites the gas is oxygen. This is a simple but effective test
for oxygen. There are sometimes confusions as the splint can create a pop very slightly on re-
ignition, which sometimes is mistaken for hydrogen. A hydrogen pop is much more violent,
sometimes enough to completely extinguish the splint.
source: ( Santa Monica College, 2020)
Physical Properties of Common Gases
Name and formula Colour Odour Effect on litmus
Oxygen (O2) Colourless Odourless Neutral
Carbon dioxide (CO2) Colourless Odourless Turns red
Hydrogen (H2) Colourless Odourless Neutral
Chlorine (Cl2) Yellow green Choking smell Bleaches
Ammonia (NH3) Colourless Choking smell Turns blue
Reference
Blackman, S., Bernard, M., Dalgety, F., & Sadoo, d. S. (2000). Science in Daily Life Bk. 2.
Georgetown, Guyana: Ministry of Education, Guyana.
- https://chemstuff.co.uk/analytical-chemistry/tests-for-
gases/#:~:text=Oxygen%20supports%20combustion%20so%20a,but%20effective%20tes
t%20for%20oxygen.
- https://www.bbc.co.uk/bitesize/guides/z6dtgwx/revision/1#:~:text=Carbon%20dioxide%
20reacts%20with%20calcium,turns%20milky%20or%20cloudy%20white.
- https://www.goodscience.com.au/year-9-chemistry/acid-metal-reactions/
- https://en.wikipedia.org/wiki/Splint_(laboratory_equipment)#:~:text=with%20an%20acid
).-,Burning%20splint%20test,distinctive%20'squeaky%20pop'%20sound.
Week: Ten
Lesson: Two
Worksheet: Identifying Gases
Circle the correct response to the questions below.
When a burning splint is placed near the opening of a test tube containing this gas, a
popping sound occurs.
1. The clue given above is used to identify
A. hydrogen
B. oxygen
C. carbon dioxide
D. chlorine
2. When moist litmus paper is placed in a test tube of this gas, it bleaches
A. hydrogen
B. oxygen
C. carbon dioxide
D. chlorine
3. Which gas is colourless, odourless and turns litmus red
A. hydrogen
B. oxygen
C. carbon dioxide
D. chlorine
4. The presence of NH3 changes litmus to ……………………
A. red
B. blue
C. orange
D. yellow
5. Dilute hydrochloric acid is added to a colourless solution. Bubbles appear immediately
and this gas turns limewater cloudy. What ion was present in the solution?
A. carbonate
B. sulphate
C. nitrate
D. chloride
Identifying substances
S N E G Y X O P W S
A S P L I N T L B S
I R E T A W E M I L
N P G L O W I N G V
O H Y D R O X I D E
M I L K Y U C I W Z
M O E N I R O L H C
A N N E G O R D Y H
S S E L R U O L O C
P O P P I N G W L I
AMMONIA CHLORINE COLOURLESS
GLOWING HYDROGEN HYDROXIDE
IONS LIMEWATER MILKY
ODOURLESS OXYGEN POPPING
SPLINT
Week: Ten
Lesson: Three
Topic: Review
Part 1: Fill in the blanks
A ____________ taste is a characteristic property of all acids in aqueous solution.
Acids react with some metals to produce ____________ gas.
Because aqueous acid solutions conduct electricity, they are identified as ____________.
Acids react with bases to produce a ____________ and water. Acids turn
____________ different colors. Bases tend to taste ____________ and feel
____________.
Like acids, aqueous basic solutions conduct ____________, and are identified as ____________.
Bases react with ____________ to produce a salt and ____________. Bases turn
____________ different colors.
(a) The most commonly used natural indicator is__________________________and is
extracted from______________________________
(b) Aqueous solution of baking soda is bitter in taste and feels soapy on touching because
it contains______________________________
(c) __________________are used to test whether a substance is acidic or basic in nature.
(d) ____________________change their colour when added to a solution containing an
acidic or basic substance.
(e) Lemon juice, orange juice taste sour because they contain_______________________
(f) The solutions which do not change the colour of either blue or red litmus are called
____________________solutions.
(g) Turmeric and litmus are _________ acid-base indicators..
(h) In neutralization reaction heat is always___________________________________.
(i) Salts may be____________________________or_____________________in nature.
(j) Chemically milk of magnesia is______________and baking soda is_______________
(k) China rose indicator turns__________________________solution to dark pink
and______________________solution to green
(l) The correct way of making a solution of acid in water is to _________
Part 2A: Write word equations for the following reactions.
1. Zinc and hydrochloric acid react to make zinc chloride and hydrogen
2. Copper oxide reacts with sulfuric acid to make copper sulfate and water.
3. Magnesium and chlorine react to make magnesium chloride.
4. Copper and silver nitrate react to make copper nitrate and silver.
5. Copper carbonate and sulfuric acid react to make copper sulfate, carbon dioxide and
water.
Part 2B: Write the formula of the compounds in bold.
Part 3: Unscramble the words below to solve. Clue: Tests for gases and water
1. -GETSRIHL _________________________________________
2. DAMP RED LIMTSU EPARP _____________________________
3. DAMP ULBE UTSMIL PARPE ____________________________
4. YLCY/OLMDKIU ______________________________________
5. CIROLENH __________________________________________
6. IMNAMOA ___________________________________________
7. LMLSE _____________________________________________
8. EYOXNG ____________________________________________
9. YUKESAQ PPO _______________________________________
10. NRBCOA IIOXEDD ____________________________________
11. YDNHREGO __________________________________________
Part 4: Complete the Venn diagram by filling in the notes in the correct places.
Complete the table below
Bases Uses in the Home/Industries
Sodium Hydroxide
Potassium Hydroxide
Calcium Hydroxide
Ammonium Hydroxide
INTEGRATED SCIENCE GRADE 8
Week: Eleven
Lesson: One
Topic: Neutralization
Content
A neutralization reaction can be defined as a chemical reaction in which an acid and base react
together to form a salt and water as products. A salt is an ionic compound composed of a cation
from a base and an anion from an acid.
Examples of Acids ad Bases
Below is an example of the reaction between solutions of hydrochloric acid and sodium hydroxide.
The overall equation for this reaction is:
Examples of other Acid – Base reactions
How to name the salt formed in a neutralization reaction?
source: (KS4 Chemistry Chemical Reactions, n.d)
Remember
Reference
https://courses.lumenlearning.com/cheminter/chapter/neutralization-reaction-and-net-ionic-
equations-for-neutralization-reactions/
Neutralisation. - ppt download (slideplayer.com)
Week: Eleven
Lesson: One
Worksheet: Neutralization
Circle the correct response to each question.
1. A neutralization reaction will always produce.
A. water & salt
B. water
C. salt
D. water & carbon
2. NaCl is a/an ...
A. acid
B. base
C. salt
D. water
3. What are the products of the following reaction?
A. H20 and NaOH
B. H2O and Na2SO4
C. H2O only
D. H2O and H2SO4
4. A salt is composed of
A. a cation from a base and an anion from an acid.
B. a cation from an acid and an anion from a base
C. cation only
D. anion only
5. What are the products of the neutralization reaction between HCl and LiOH
A. H2O
B. H3O+ and OH
C. LiCl
D. H2O and LiCl
6. A salt is an ionic compound that is
A. an acid
B. a base
C. both acid and base
D. neither an acid nor a base
7. The chemical formula for potassium hydroxide is
A. POH
B. KOH
C. PHO
D. KHO
8. Our stomach contains hydrochloric acid. To relieve indigestion of food what should we
intake?
A. water
B. hydrochloric acid
C. milk of magnesia
D. orange juice
9. The neutralisation reaction between hydrochloric acid and sodium hydroxide
can be written as
A. Hydrochloric acid + Sodium hydroxide → Sodium chloride + Water
B. Hydrochloric acid +Sodium hydroxide → Potassium chloride + Water
C. Hydrochloric acid + Sodium hydroxide → calcium chloride + carbonhydroxide
D. Sodium hydroxide + Water → Sodium chloride + Hydrochloric acid
10. To produce potassium chloride by the reaction
illustrated you need.
A. sodium hydroxide + hydrochloric
acid
B. potassium hydroxide +
hydrochloric acid
C. sodium chloride + potassium
hydroxide
D. potassium sulfate +
hydrochloric acid
Week: Eleven
Lesson: Two
Topic: Identifying Gases
Content
Identifying Hydrogen - Burning splint test
A splint is lit and held near the opening of the tube, then the stopper is removed to expose
the splint to the gas. If the gas is flammable, the mixture ignites. This test is most commonly
used to identify hydrogen, which extinguishes with a distinctive 'squeaky pop' sound.
Hydrogen is easily ignited, as it is flammable over a wide range of concentrations in air,
making this test quite robust. If the gas is non-flammable, the burning splint will be
extinguished.
source : ( Good Science, n.d)
Identifying Carbon Dioxide
Carbon dioxide reacts with calcium hydroxide (lime water) solution to produce a white
precipitate (solid) of calcium carbonate. Limewater is a solution of calcium hydroxide. If
carbon dioxide is bubbled through limewater, the limewater turns milky or cloudy white.
source: (GCSE OCR Gateway, n.d)
Identifying Oxygen
Oxygen supports combustion so a good method of testing for oxygen is to take a glowing
splint and place it in a sample of gas. If it re-ignites the gas is oxygen. This is a simple but
effective test for oxygen. There are sometimes confusions as the splint can create a pop
very slightly on re-ignition, which sometimes is mistaken for hydrogen. A hydrogen pop
is much more violent, sometimes enough to completely extinguish the splint.
source: ( Santa Monica College, 2020)
Physical Properties of Common Gases
Name and formula Colour Odour Effect on litmus
Oxygen (O2) Colourless Odourless Neutral
Carbon dioxide
(CO2)
Colourless Odourless Turns red
Hydrogen (H2) Colourless Odourless Neutral
Chlorine (Cl2) Yellow green Choking smell Bleaches
Ammonia (NH3) Colourless Choking smell Turns blue
Reference
Blackman, S., Bernard, M., Dalgety, F., & Sadoo, d. S. (2000). Science in Daily Life Bk.
2. Georgetown, Guyana: Ministry of Education, Guyana.
- https://chemstuff.co.uk/analytical-chemistry/tests-for-
gases/#:~:text=Oxygen%20supports%20combustion%20so%20a,but%20effective
%20test%20for%20oxygen.
- https://www.bbc.co.uk/bitesize/guides/z6dtgwx/revision/1#:~:text=Carbon%20
dioxide%20reacts%20with%20calcium,turns%20milky%20or%20cloudy%20white
.
- https://www.goodscience.com.au/year-9-chemistry/acid-metal-reactions/
- https://en.wikipedia.org/wiki/Splint_(laboratory_equipment)#:~:text=with%20an
%20acid).-,Burning%20splint%20test,distinctive%20'squeaky%20pop'%20sound.
Week: Eleven
Lesson: Two
Worksheet: Identifying Gases
Circle the correct response to the questions below.
When a burning splint is placed near the opening of a test tube containing this gas, a
popping sound occurs.
1. The clue given above is used to identify
A. hydrogen
B. oxygen
C. carbon dioxide
D. chlorine
2. When moist litmus paper is placed in a test tube of this gas, it bleaches
A. hydrogen
B. oxygen
C. carbon dioxide
D. chlorine
3. Which gas is colourless, odourless and turns litmus red
A. hydrogen
B. oxygen
C. carbon dioxide
D. chlorine
4. The presence of NH3 changes litmus to ……………………
A. red
B. blue
C. orange
D. yellow
5. Dilute hydrochloric acid is added to a colourless solution. Bubbles appear
immediately and this gas turns limewater cloudy. What ion was present in the
solution?
A. carbonate
B. sulphate
C. nitrate
D. chloride
Identifying substances
S N E G Y X O P W S
A S P L I N T L B S
I R E T A W E M I L
N P G L O W I N G V
O H Y D R O X I D E
M I L K Y U C I W Z
M O E N I R O L H C
A N N E G O R D Y H
S S E L R U O L O C
P O P P I N G W L I
AMMONIA CHLORINE COLOURLESS
GLOWING HYDROGEN HYDROXIDE
IONS LIMEWATER MILKY
ODOURLESS OXYGEN POPPING
SPLINT
Week: Eleven
Lesson: Three
Topic: Review
Part 1: Fill in the blanks
A ____________ taste is a characteristic property of all acids in aqueous solution.
Acids react with some metals to produce ____________ gas.
Because aqueous acid solutions conduct electricity, they are identified as ____________.
Acids react with bases to produce a ____________ and water. Acids turn
____________ different colors. Bases tend to taste ____________ and
feel ____________.
Like acids, aqueous basic solutions conduct ____________, and are identified as
____________.
Bases react with ____________ to produce a salt and ____________. Bases turn
____________ different colors.
(a) The most commonly used natural indicator
is__________________________and is extracted
from______________________________
(b) Aqueous solution of baking soda is bitter in taste and feels soapy on touching
because it contains______________________________
(c) __________________are used to test whether a substance is acidic or basic in
nature.
(d) ____________________change their colour when added to a solution
containing an acidic or basic substance.
(e) Lemon juice, orange juice taste sour because they
contain_______________________
(f) The solutions which do not change the colour of either blue or red litmus are
called ____________________solutions.
(g) Turmeric and litmus are _________ acid-base indicators..
(h) In neutralization reaction heat is
always___________________________________.
(i) Salts may be____________________________or_____________________in
nature.
(j) Chemically milk of magnesia is______________and baking soda
is_______________
(k) China rose indicator turns__________________________solution to dark
pink and______________________solution to green
(l) The correct way of making a solution of acid in water is to _________
Part 2A: Write word equations for the following reactions.
1. Zinc and hydrochloric acid react to make zinc chloride and hydrogen
2. Copper oxide reacts with sulfuric acid to make copper sulfate and water.
3. Magnesium and chlorine react to make magnesium chloride.
4. Copper and silver nitrate react to make copper nitrate and silver.
5. Copper carbonate and sulfuric acid react to make copper sulfate, carbon dioxide
and water.
Week: Twelve
Lesson: One
Topic: The Human Skin
Content
The skin is a soft outer covering of humans and all other animals with a backbone. The
skin is the largest organ of the body. It is our first line of protection against the outside
environment, it houses one of our five senses, it absorbs sunlight for vitamin D and heat,
and regulates our internal temperature.
Structure of the Skin
Nerves: These nerves sense and transmit heat, pain, and other sensations.
Sweat Glands: These glands are located in the epidermis and produce moisture
(sweat) that is secreted through tiny ducts onto the surface of the
skin.
Blood Vessels: Veins and arteries carry nutrients and oxygen-rich blood to the
cells that make up the layers of skin and carry away waste
products.
Hair: Helps with regulating the body temperature
Sweat Pore: Are small openings on the surface of the skin that allow sweat to
exit the body.
Functions of the skin
The skin has three major functions.
1. Protection - One of the basic functions of the skin is protection. Over the majority
of your body the skin is around 2mm thick. In some areas, like your eyelids, it's
thinner, while in other areas, like the soles of your feet, it's much thicker. The skin
helps to keep bad stuff out of our body, like germs and dirt that can cause
infection. It also keeps good stuff in, like fluids such as water and blood.
2. Sense of Touch - The skin also houses one of our five senses: touch. In our skin
are thousands and thousands of sensors or receptor cells. These sensors send
information to the brain about things we touch. They can tell the brain if it's hot,
cold, rough, smooth, or painful. Different areas of our body have more receptor
cells than others. Our hands, feet, and lips all have extra receptors making those
areas even more sensitive. There are actually different types of receptor cells for
each type of sensation.
3. Temperature Control - The skin plays a large role in regulating our body's
temperature. When we get too hot it sweats to help cool us off. It can also widen
the skin's blood vessels to get more blood near the skin where it can cool off. At
the same time the skin can narrow the blood vessels to help us warm up. By
controlling blood flow and sweat, the skin regulates our body's temperature.
Layers of the skin
The skin has three primary layers. Each one has its own function.
Epidermis - The epidermis, is super thin on some parts of your body (your eyelids) and
thicker on others (the bottoms of your feet). The epidermis is the layer of skin in charge
of:
Making new skin cells: This happens at the bottom of the epidermis. The skin
cells travel up to the top layer and flake off, about a month after they form.
Giving skin its color: The epidermis makes melanin, which is what gives your
skin its color.
Protecting your body: The epidermis has special cells that are part of your
immune system and help you stay healthy.
Dermis - The dermis is thicker than the epidermis. The dermis houses blood cells, hair
follicles, and sweat glands. The jobs of the dermis include:
Making sweat: There are little pockets called sweat glands in the dermis. They
make sweat, which goes through little tubes and comes out of holes called pores.
Sweating keeps you cool and helps you get rid of bad stuff your body doesn't
need.
Helping you feel things: Nerve endings in the dermis help you feel things. They
send signals to your brain, so you know how something feels if it hurts (meaning
you should stop touching it), is itchy or feels nice when you touch it.
Growing hair: The dermis is where you'll find the root of each tiny little hair on
your skin. Each root attaches to a tiny little muscle that tightens and gives you
goose bumps when you are cold or are scared.
Making oil: Another type of little pocket, or gland, in your skin makes oil. The
oil keeps your skin soft, smooth and waterproof. Sometimes the glands make too
much oil and give you pimples. (See Acne: Pimples and Zits.
Bringing blood to your skin: Blood feeds your skin and takes away bad stuff
through little tubes called blood vessels.
Hypodermis (Subcutaneous fat layer) - is the deepest and thickest layer of the skin. It lies
under the dermis and connects the skin to muscles and bone. This layer plays an
important role in your body by:
Attaching the dermis to your muscles and bones: This layer has a special
connecting tissue that attaches the dermis to your muscles and bones.
Helping the blood vessels and nerve cells: Blood vessels and nerve cells that
start in the dermis get bigger and go to the rest of your body from here.
Controlling your body temperature: The subcutaneous fat is the layer that helps
keep your body from getting too warm or too cold.
Storing your fat: This fat pads your muscles and bones and protects them from
bumps and falls.
Care of our Skin
It is important for us to take special care of our skin since it plays a very major role in
protecting us. Listed below are some thing that we can do to care our skin.
1. Bathe at least twice a day with soap and water.
2. Use a wash-cloth to rub away dirk from exposed surfaces of the skin such
as hands, arms and face.
3. Wounds, bruises and other damage to the skin should be treated by a
doctor.
Important facts on the skin
1. The skin renews itself completely in 28 days and sheds 30,000 to 40,000 dead cells
per minute while it renews itself. An average human sheds 9 pounds of skin cells in
a year.
2. The human skin is home to 1000 species of bacteria.
3. The thickest skin in humans is found on the soles of the feet, whereas the thinnest
is found on the eye lids.
4. On a hot day, the sweat glands can produce up to 3 gallons of sweat in a day.
5. Goose bumps help retain a layer of warm air over our body.
References
Biology for Kids: The Skin (ducksters.com)
Structure and Function of the Skin - Biology for Kids | Mocomi
Human skin. layered epidermis with hair follicle, sweat and sebaceous glands. healthy
skin anatomy medical vector | CanStock (canstockphoto.com)
Week: Twelve
Lesson: One
Worksheet: The Human Skin
Content
Complete the word search below.
J X D A Y Q O X D E Z T F M F V E T J H D M F V
Y O K E U S I M R E D I P E D O F G S P U B M H
Q D O W H J T G Q E G M T L E U O W B S E N U R
E N O E R C R Y E F S K V X R D L K Q K Z E S I
E F K N A I B C T Q Z H B A M M L K R V E R O M
Z Y P M T P G B E G F M R E I M I R H F M N M P
J M E L A N O M A F L O B X S Y C A L R I D A W
Z H X J Q J O A G N O C S X P Y L Z U K O O I M
Z T A C U Q X B G H I O P F F F E Q S B R U A W
R J R X B O P W L W E Q X H X A H A N M F I U M
S Z J T S I G O L O T A M R E D R J N P N X T M
D X M F E I N J D N A L G S U O E C A B E S X P
L U K X X Q O W K U E R Z F Z B S L G P F M J L
S O U K N N E S N S D E E D W U F X M E Q G V Q
M T L O S U B C U T A N E O U S L A Y E R Y A A
S Q R R V W S Z B J E X S E F H F X M R H M Q R
Y M A A J A G F E Y M E L A N I N I P C F R M U
G L U W W V W L D C A X V Y O P N C U I I U Z D
M Z R B T S Z F Y E G A E U P S B G K A Q F C H
T C A P E J Z U M P N P B F Q D V G H B T S U Z
H V D H P S N N Y S P C J J V E N A M E Z C E I
L X R L G J K U A X J G A I X T S A A D H U V U
H A M O N I C R A C L L E C S U O M A U Q S G E
E J E J A M O N I C R A C L L E C L A S A B E G
sebaceous gland sebum follicle hair skin dermatologist acne
eczema warts melanin melanoma squamous cell carcinoma basal cell
carcinoma subcutaneous layer epidermis dermis
Fill-in the blank spaces with the appropriate words.
1. The outer layer of skin is the _______________ layer. The inner layer is the
________________ layer. Which layer is the thickest? ___________________ What is
the subcutaneous layer?
2. Epidermis contains a few distinct cell types. Fill in the name of the cell type that fits
each description:
a. Most numerous cell type, this cell produces keratin which helps to
waterproof skin: _________________________
b. This type of cell produces the pigments which give skin its color:
__________________________.
3. The epidermis is ________________________; that is it has no blood supply of its
own, similar to epithelial tissue.
4. Match the following disease or disorder with the description that best describes the
condition:
A. Acne B. Athletes Foot C. Burns D. Cancer E. Boils & Carbuncles
_____________Uncontrolled cell growth
_____________A fungus infection that invades and lives off of the dead outer layers of
the skin.
_____________A sometimes hereditary, chronic condition characterized by reddened
epidermal lesions covered with dry, silvery scales.
_____________An inflammatory condition of infected sebaceous glands
_____________Tissue injury caused by thermal, electrical, chemical or radioactive
sources.
5. Which is not a function of the skin?
a. Protection against mechanical injury
b. Protection against foreign invaders c. Regulation of body heat
d. All of the above are functions
6. The layer of skin that lacks blood vessels is …
a. Subcutaneous.
b. Dermis.
c. Integument.
d. Epidermis.
7. The dermis does not contain …
a. Sebaceous glands.
b. Hair follicles.
c. Mucous glands.
d. Nerves.
8. The color of human skin depends upon …
a. Whether the blood within the skin is well oxygenated.
b. The number of underlying blood vessels.
c. The kind and amount of pigment.
d. All of the above.
9. The amount of melanin produced in the skin is determined by the …
a. Number of melanocytes.
b. Activity of melanocytes.
c. Diet.
d. Proximity of blood vessels to the skin.
10. The dermis is primarily composed of which tissue type?
1. Nervous
2. Muscle
3. Connective
4. Epithelial
Week: Twelve
Lesson: Two
Topic: The Tongue
Content
The tongue is a fleshy muscular organ in the mouth which is attached at the back to the floor of
the buccal cavity (mouth cavity).
Structure of the Tongue
The diagram below shows the areas of the tongue used for tasting.
The upper or top section of the tongue is covered with tiny little taste buds that contain what is
called ‘taste receptors’. These help to taste the food and liquids that we consume.
When you look at your tongue you can see little bumps all over it. These are called ‘papillae’ and
our taste buds are situated on top of the papillae. The papillae present on the tongue gives it a
rough texture.
Functions of the Tongue
The main function of the tongue is tasting, however, the tongue has other functions. Listed below
are you will find those functions.
1. The tongue helps in mixing saliva with food during chewing (which is important for
digestion).
2. Helps with swallowing food and pushing it into the esophagus,
3. Helps in getting the taste of food.
4. Is essential to talking and speaking.
Care of our Tongue
1. Cleaning your tongue every time you brush using a toothbrush. Clean your tongue in a
downward motion to expel all the accumulated bacteria, and never apply a lot of pressure when
doing so.
2. Apply a thin layer of your toothpaste on your tongue before cleaning it. This makes
removing bacteria from your tongue much easier.
3. After cleaning your tongue, rinse your mouth thoroughly with water. Use a mouthwash once
in a while as that keeps foul odour at bay. Using a mouthwash daily is not advised as it can
cause dryness in the mouth.
4. A saline water (salt water) solution can be used to rinse your mouth to keep your tongue
clean. A glass of lukewarm water with half a teaspoon of salt is recommended.
5. Sometimes, a whitish layer on your tongue can be a sign of a fungal infection, in which case
you should go for a professional clean-up.
6. Drinking lots of water is good for your tongue as it helps in washing out all the accumulated
food and bacteria. Also, discoloration of the tongue can often be caused by dehydration, which
is why drinking adequate amounts of water (10-12 glasses a day) is vital.
References
Tongue Structure - Parts and Functions of Tongue (byjus.com)
How Your Tongue Works | HowStuffWorks
How To Take Care Of Your Tongue? - By Dr. Anupreet Kaur Choudhury | Lybrate
Week: Twelve
Lesson: Three
Worksheet: The Human Tongue
Indicate whether the following statements re True or False
True | False 1. The tongue is a flexible, muscular organ in the mouth of most organisms that
manipulates and tastes food.
True | False 2. A goat has a specialized tongue that it uses to smell for food.
True | False 3. The long and slender tongue of a giraffe grabs leaves from the branches of tall
trees.
True | False 4. A human tongue is divided into two, namely the base and the posterior part.
True | False 5. The action of the tongue is involved in the production of sounds.
True | False 6. The anterior surface of the tongue is located near the back of the throat.
True | False 7. The median sulcus divides the anterior of the tongue into symmetrical halves.
True | False 8. Our tongue's posterior part is attached to the roof of the mouth.
True | False 9. A way to clean the tongue is by using a scraper to remove extra particles on the
tongue.
True | False 10. Different taste buds are found all over the tongue's posterior surface
11. Label the parts of the tongue to show what foods they taste and then complete the table
shown below.
Week: Twelve
Lesson: Three
Topic: Review
Study the diagram below then answer the questions that follow.
Indicate whether the following statements are True or Fales.
Circle the correct response to the questions below.
1. What animal has a black tongue?
a. Giraffe
b. Rabbit
c. Human
d. Cat
2. About how many taste buds, or papillae, do you have?
a. Anywhere between 3,000 and 10,000
b. Anywhere between 300 and 1,000
c. Anywhere between 30 and 100
d. Anywhere between 3 and 10
3. What muscles move the tongue body forward, back, up, and down?
a. Intrinsic tongue muscles
b. lip muscles
c. velum
d. Extrinsic tongue muscles
4. Follicle, root, and pigment are all words that tell about my _____.
a. hair
b. tongue
c. nose
5. Which organ contains the three smallest bones existing in the human body?
a. ear
b. eye
c. brain
d. tongue
6. The tiny little bumps on our tongues are
a. tongue tasters.
b. flavor sensors.
c. taste buds.
7. The tip of the tongue detects sweet tastes.
a. True
b. False
8. The back of the tongue detects bitter tastes.
a. True
b. False
9. Hypoglottis is the underside of the tongue.
a. True
b. False
10. ______________tongue muscles shape the tongue body (bunch, flatten, curl tip up or
down)
a. Intrinsic
b. Extrinsic
Week: Thirteen
Lesson: One
Topic: At Home Science Projects
Why do apples turn brown?
Aim: To find out how chemical reactions work to keep apples (or pears) fresh even after they
are cut.
Materials:
An apple or pear
Sharp knife
Lemon juice
Small bowl (big enough to fit half
the apple or pear)
Clock/timer
Paper plates
Pen and paper
Adult help
Method
1. Use your pen and paper to make two labels, one
reading “control” and the other reading “lemon.”
2. Pour lemon juice so it completely covers the
bottom of the bowl.
3. With adult help, cut the apple in half from top
to bottom.
4. Take one apple half and place it cut side
down into the bowl of lemon juice. Leave it for
two minutes. The other apple half without
lemon juice is your ‘control’ sample that lets
you see what normally happens to a cut apple.
5. Observe the color of both apple halves, then
place them white part up on the plates, with the
corresponding labels nearby.
6. Observe the apples again at 10-minute
increments, up to 30 minutes. Note any color
changes and/or differences in appearance.
7. Look at the apples again periodically
throughout the day. What do you find?
8. Record all observations.
Questions
1. Name the substance released from apples or pears that causes them to go brown.
2. What does this substance react with to cause the browning?
3. Why do most plants contain this substance?
4. The browning creates an antibacterial effect. How is this beneficial to the plant?
5. What is the function of the lemon juice? How does it do its job?
Week: Thirteen
Lesson: Two
Topic: At Home Science Projects
Volcanic Eruption Science Projects
You can demonstrate a volcanic eruption using some simple household items.
Method
1. Use a small plastic bottle (the size 20-oz soft drinks come in works well). Fill the bottle
halfway (1 to 1.5 cups) of vinegar. Add a few drops of red food colouring to the acid in
the bottle.
2. Use clay or playdough to make a ‘mountain’ around the bottle.
3. Place one tablespoon of baking soda into a small piece of tissue paper, tying the ends
with string.
4. Now drop the baking soda ‘bomb’ into the bottle with the acid.
5. Record your observations.
Questions
1. State which substance is the acid and which is the base.
2. What is the pH of baking soda?
3. Name the type of reaction that occurs when the baking soda is dropped into the bottle
with the acid.
4. Write a simple word equation to show this reaction.
5. Give the name of any gas or gases produced during this reaction.
6. How can you determine when a gas is produced in a reaction?
Week: Thirteen
Lesson: Three
Topic: At Home Science Projects
Title: Crystal Growing
Aim: To grow crystals at home – making rock candy.
Materials:
1 1/2 cups of white sugar
1 cup of water
Small plate
A spoon
A glass
Wax paper
Saucepan
Stove
Several 250 ml beakers or small clean jars
Cake pop sticks or wooden skewers
Food coloring pack (optional)
An adult to help you
Note: You can make Rock Candy without sticks. Use a piece of clean cotton string or thread.
Follow steps 2-7 below then dip the string into the solution so that half of the string is coated.
Take the string out and let it dry. Once the string has dried, tie the clean end around a pencil and
put the dipped end back into the glass of sugar water solution, balancing the pencil across the rim
of the glass. Make sure the string does not touch the bottom or the sides of the glass, or your
crystals will not form right! When your piece of “rock candy” is as big as you want it to be
(about one week), take it out of the glass, let it dry, and enjoy!
1. Fill a glass with water, pour some sugar on a small plate, and lay out a sheet of waxed
paper. Dip one end of each stick (cut pointed ends off if you use skewers) into the water
and then roll it in the sugar, tapping it gently to remove excess. Set each stick to dry on
the waxed paper.
2. Pour the cup of water into the saucepan and add 1/2 cup sugar. Stir it well until no more
sugar will dissolve. Add more sugar (1/2 cup at a time) until you can’t get any more to
dissolve even after stirring for several minutes. You should end up with about 1 1/2 cups
sugar dissolved in the saucepan. It’s OK if there is some undissolved sugar at the bottom
of the pan. (You now have a saturated sugar solution.)
3. Ask an adult to help you heat the sugar mixture on the
stove until it boils, stirring the whole time. Turn the
heat to medium-low and keep stirring until all the sugar
dissolves. (Now you have made a supersaturated
solution!)
4. Keep cooking the liquid and stirring it until it becomes clear, but not for more than 5
minutes, or it will get too hot and turn into hard candy. Turn off the stove as soon as it
starts to look clear.
5. Move the pan off the heat and allow it to cool down
until the pan is no longer hot (the sugar solution will
still be slightly warm).
6. Have an adult slowly pour the thick sugar solution into the jars. Fill each about 2/3 full,
or enough so that sugar solution will cover several inches of your sugar-coated sticks.
7. Add 5-6 drops of food coloring to each jar and stir.
(Optional: Only do this step if you want to make
different colors of rock candy!)
8. Once the solution is cool and the sugar-coated sticks are
completely dry, place several sticks into each jar.
9. Carefully move the jars to a place where they won’t be
disturbed. Check them every other day and gently stir the
sticks around in the sugar solution to break up any large
crystals forming on the surface.
10. Within a few days, you should start to see crystals growing
on the sticks. After about one week, you will probably have a
lot of crystals. When your “rock candy” crystals are as big as
you want them to be, take them out of the jars and set each
color of candy in a clean glass to dry.
Questions
1. What is a saturated solution?
2. What is a supersaturated solution?
3. Why did sugar molecules start to form on the sticks?
4. The sugar on the sticks are called “seed” molecules and the sugar molecules in the
solution attach themselves to the seed molecules. Why do you think this occurs?
5. Do you think that the crystals would form if the solution was just saturated?
Explain your answer.
Week: Fourteen
Lesson: One
Worksheet: General Review
Answer All Questions
1. (a) Define the term force and state its SI unit (2mks).
(b) Briefly explain Newton’s first and second law of motion (4mks)
(c) The wind pushes a paper cup along the sand at a beach. The cup has a mass of 0.025 kg
and accelerates at a rate of 5 m/s2. How much force is the wind exerting on the cup? (3mks)
2. (a) Describe two ways in which friction helps you on a daily basis. (4mks)
(b) List two ways in which friction can be reduced (2mks)
3. (a) Match one item of column A to one item of column B (4mks)
Column A Column B
Lift a car so you can change a wheel A crowbar
Lift a bucket of cement to the top of a building under construction An auger
Remove a big rock from the ground A jack
Drill a hole through a board A pulley
(b) Label the load, fulcrum and effort on each type of lever given below and identify the
levers as 1st, 2nd or 3rd class. (6mks)
(c) Identify the type of simple machine for each example given below (5mks).
- a bath tub
- an electric fan
- an axe
-a knife
- a ramp
4. Differentiate between the following terms
(i) atoms and molecules (2mks)
(ii) elements and compounds ((2mks)
5. List the elements and the number of each atoms present in the formula in the following
compounds. ( 2mks each )
(i) CuSO4
(ii) CuCl2
(iii) CuO
(iv) ZnS
6. State whether each of the following is a physical or chemical property
(i) the sulphur is yellow
(ii) iron reacts with sulphur to give heat and a flame
(iii) Baking soda reacts with acid to produce bubbles and a gas
(iv) Helium is less dense than air, hence a Helium balloon floats
(1mk each, 4mks )
7. (a) The Kinetic Theory is based about three theories of matter. Briefly explain the three
theories. (5mks)
(b) Complete the concept map given below. (6mks)
8. Fill in the blanks
(i) In the presence of an acid, blue litmus changes to …………………
(ii) ………………. acid is found in oranges
(iii) I am used in the production of shampoos, soaps and disinfectants …………..
(iv) Water-soluble bases are called ……………
(v) When an acid reacts with a metal , …………….. and ………… are produced
(1mks each , 5mks)
9. Complete the word equations given below
(a) Hydrochloric acid and sodium (2mks)
(b) sulfuric acid and iron (ii) carbonate (2mks)
10. (a) What is a neutralization reaction (2mks)
(c) Write an example of neutralization reaction (5mks)
Week: Fourteen
Lesson: Two
Worksheet: Review-Matter
Part 1: Column A lists a substance. In Column B, list whether the substance is an element (E), a
compound (C), a Heterogeneous Mixture (Het), or a Homogeneous (Homo). In Column C, list
TWO physical properties of the substance.
Column A Column B Column C
1. Summer Sausage
2. Steam
3. Salt Water
4. Pencil lead (Pb)
5. Dirt
6. Pepsi
7. Silver (Ag)
8. Toothpaste (Na2HPO4)
9. A burrito
10. Italian Dressing
11. Chicken Soup
12. Lemonade
Part 2: Answer the questions below using your own words.
1) Define MIXTURE in your own words.
2) List two properties of mixtures.
3) Complete the table below by filling in the type of mixture: Heterogeneous
Mixture / Solution / Suspension
Example Type of Mixture
a) saltwater
b) a garden salad
c) A bag of different colored jelly beans
e) Strawberry ice cream with fruit
f) Instant coffee in water
4) Complete the VEN Diagram below by listing the similarities and differences
between Homogeneous and Heterogeneous Mixtures
Homogeneous Heterogeneous
Differences Differences
Similarities
Part 3: Circle the correct response for each question below.
1. Of the four boxes shown, which one represents a model of elements only?
A. B and C
B. A and C
C. A, C and D
D. B and D
2. Which one of the following elements has the symbol C?
A. Copper
B. Calcium
C. Carbon
D. Chlorine
3. One of the following substances is not an element. Which one is it?
A. water
B. hydrogen
C. mercury
D. nitrogen
4. Elements are sometimes written with two letters. Magnesium is one of these elements.
What is the symbol for magnesium?
A. M
B. Mg
C. MG
D. mg
5. Approximately how many elements are there on earth?
A. 1000
B. 100
C. 10
D. 20
6. A compound is a molecule that contains at least two different elements. Each of the
following substances in the list is a molecule. One of these is not a compound. Which one
is it?
A B
C D
7. Which one of the following statements about compounds is correct?
A. At least one of the elements in a mixture must be a gas.
B. The elements in a compound are always present in the same ratio.
C. properties of a compound are the same as the properties of the elements of which it is
made up.
D. It is easy to separate a compound into the elements that it is made from.
8. How many atoms are there in a molecule of CH4?
A. 3
B. 4
C. 2
D. 5
9. Which of the following statements is correct?
A. Air is a mixture and carbon is a compound.
B. Carbon is a mixture and air is a compound.
C. Table salt is a mixture and carbon is a compound.
D. Air is a mixture and table salt is a compound.
10. How many different types of the atom may be present in a compound?
A. Two or more different types
B. Three or more different atom types
C. Exactly four different atom types
D. Only one type of atom
Use your chart to determine who is responsible for the following:
1. Stated that in a chemical reaction, atoms are combined, separated or rearranged
_______________
2. Discovered the nucleus of the atom
_______________
3. Stated that atoms of a particular element are all alike
_______________
4. First discovered there are particles smaller than an atom
_______________
5. Stated that atoms of different elements combine in small whole number ratios
_______________
6. Discovered that atoms of each element contain a unique + charge in nuclei
_______________
7. Discovered the charge to mass ratio of the electron
_______________
8. Stated that atoms cannot be subdivided, created or destroyed
_______________
9. Discovered the neutral particle in the nucleus
_______________
10. Stated that atoms of one element are different from atoms of another element
_______________
11. Discovered the charge on an electron
_______________
12. First stated that all matter was made of indivisible atoms
_______________
States of Matter
1
2
3
4
5 6 7
8
9
10
11 12
13 14 15
16 17
18
19
Across
2. The pressure caused by the collisions of
particles in a vapor with the walls of a container
3. A reversible physical change that occurs
when a substance changes states of matter
6. The energy a substance must absorb into
change from solid to liquid
9. A description of change in which a system
absorbs energy from it's surroundings
13. The process that changes a substance from
liquid to gas based on temperature
15. The state of matter in which ba material has
neither a definite shape or a definite volume
16. The state of matter in which materials have a
definite shape and a definite volume
17. The direct proportion of the volume of a gas
to it's temperature if it is constant
18. The state of matter in which a material has a
definite volume but not a definite shape
19. A result of force distributed over an area
Down
1. The phase change in which a substance
changes from a gas or vapor to a liquid
4. The phase change in which a substance
changes from liquid to gas
5. The energy a substance must absorb in order
to change from solid to liquid
7. The energy an object has due to it's motion
8. The inverse relationship between volume and
gas
10. The phase change in which a gas or vapor
changes directly into a solid without first
changing into a liquid
11. A description of change in which a system
releases energy to it's surroundings
12. A temperature of zero Kelvins
14. The phase change in which a substance
changes from a solid to a gas or vapor without
changing to a liquid first
Week: Fourteen
Lesson: Three
Worksheet: Review-Matter
Part 1: Complete the crossword puzzles below.
Chapter 6 - Acids, Bases, and Solutions
1 2 3
4
5 6
7 8
9
10 11 12
13
14
15 16
17
18
Across
4. A range of values used to indicate how acidic
or basic a substance is; expresses the
concentration of hydrogen ions in a solution.
8. A substance that tastes bitter, feels slippery,
and turns red litmus paper blue.
Down
1. A mixture in which particles can be seen and
easily separated by settling or filtration.
2. A mixture that contains as much dissolved
solute as is possible at a given temperature.
12. An ionic compound made from the
neutralization of an acid with a base.
13. A mixture containing a solvent and at least
one solute that has the same properties
throughout; a mixture in which one substance is
dissolved in another.
14. A substance that tastes sour, reacts with
metals and carbonates and turns blue litmus red.
15. A mixture containing small, undissolved
particles that do not settle out.
16. The part of a solution that is usually present
in the largest amount and dissolves a solute.
17. A measure of how much solute can dissolve
in a given solvent at a given temperature.
18. A mixture that has only a little solute
dissolved in it.
3. A mixture that has a lot of solute dissolved in
it.
5. A negatively charged ion made of oxygen and
hydrogen
6. A reaction of an acid with a base, yielding a
solution that is not as acidic or basic as the
starting solutions were.
7. The gradual wearing away of a metal element
due to a chemical reaction.
9. A positively charged ion formed of a
hydrogen atom that has lost it electron.
10. The part of a solution that is dissolved by a
solvent.
11. A compound that changes color in the
presence of an acid or a base.
Part 2: Match the statements to the correct word or phrase on the right.
Electrolysis
1. Decomposition of aqueous or fused chemical compounds by
passage of a direct electric current.
A. Liberates ions only
2. Covalent compounds which do not conduct electricity in
fused or aqueous state.
B. Non electrolytes
3. Electrolytes which dissociates completely. C. Strong electrolyte
4. Ions and molecules are liberated by dissociation of these
electrolytes.
D. Electrolysis
5. They allow electric current to enter or leave the electrolytic
solution.
E. Anode
6. Negatively charged particles. F. Electrodes
7. Positively charged electrode. G. Weak
8. Lead nitrate , Sodium chloride and Nitric acid. H. Anions
Part 3: Circle the correct response to the questions
1. Which of the following descriptions explains how litmus paper can be used to test for
acids?
a. Acids turn blue litmus paper red.
b. Acids keep blue litmus paper blue.
c. Acids turn red litmus paper blue.
d. Acids turn red litmus paper purple.
e. Acids turn blue litmus paper purple.
2. Coffee has a pH of 5. Is it acidic, basic, or neutral?
a. Neutral
b. Basic
c. Acidic
3. Ocean water has a pH of 8. Is it acidic, basic, or neutral?
a. Neutral
b. Acidic
c. Basic
4. Milk of magnesia has a pOH of 3.5. Is it acidic, basic, or neutral?
a. Basic
b. Acidic
c. Neutral
5. Orange juice has a pOH of 9.8. Is it acidic, basic, or neutral?
a. Neutral
b. Basic
c. Acidic
6. In which range of values would the pH of a basic solution be found?
a. >5
b. >10
c. >7
d. <7
e. <10
7. Is a solution of pH 6.9 acidic, basic, or neutral?
a. Acidic
b. Basic
c. Neutral
8. In which range of values would the pH of an acidic solution be found?
a. <7
b. >5
c. <5
d. >7
e. <10
9. Is a solution of pH 3.2 acidic, basic, or neutral?
a. Basic
b. Neutral
10. What is the pH of a neutral solution at room temperature?
11. Calcium carbonate will produce a fizz of carbon dioxide when added to lemon juice.
Based on this observation, what can be said about the pH of lemon juice?
a. <10
b. >5
c. >7
d. <7
e. <5
12. Which of the following pH values would a solution of lemon juice most likely have?
a. 2.5
b. 7.5
c. 0.0
d. 10.0
e. 5.0
13. Fill in the blanks: Litmus is a mixture of dyes extracted from lichen. It can be used to
detect if solutions are acidic or basic. It is ______ in acidic solutions and
______
14. in basic solutions.
a. red, blue
b. colorless, pink
c. green, blue
d. pink, colorless
e. blue, red
15. Which of the following substances is likely to have the lowest pH?
a. Seawater
b. Lemon juice
c. Bleach
d. Baking soda
e. Black coffee
Week: Fifteen
Lesson: One
Topic: Review
Part 1. We use chemical formulas to represent the number and identities of atoms in molecules.
For each of the chemical formula listed below, provide the name of the compound and the names
of the individual elements present.
Compound Formula Elements
1 CH4
2 C2H5OH
3 CO2
4 CuSO4
5 H2O
6 H2SO4
7 HCL
8 NaCl
9 NaOH
10 NH3
Part 2: In the table below, classify the following materials as elements, compounds or mixtures by
writing E, C or M respectively in the empty boxes.
1
air
11
milk
2
alcohol
12
nail polish
3
blood
13
nitrogen
4
cake batter
14
oxygen
5
carbon dioxide
15
salt water
6
coffee
16
sodium
7
cola
17
soil
8
eggs
18
soup
9
ice cream
19
table salt
10
iron
20
water
Week: Fifteen
Lesson: Two
Topic: Review
Part 1: In the table below, classify the following substances or mixtures as homogeneous or
heterogeneous by placing an X in the appropriate box.
HOMOGENEOUS HETEROGENEOUS
1 alcohol
2 aluminum foil
3 beach sand
4 black liquid coffee
5 cherry vanilla ice cream
6 dirty polluted air
7 flat soda pop
8 iron
9 paint
10 pure clean air
11 salad dressing
12 soil
13 spaghetti sauce
14 sugar
Part 2: Often we wish to separate mixtures into their individual components (e.g., if one is more
valuable or useful on its own) We can do this by using the differences in the physical and
chemical properties of the components. For the mixtures below, describe a method that would
allow us to separate them into their components?
____________________________________________________________________________________
____________________________________________________________________________________
5. A mixture of salt and iron fillings
________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
1 . Sugar and water
2 . Oil and water
3 . Sand and gravel
4 . A mixture of water and alcohol (ethanol)
Part 3: Provide the chemical symbols for the elements listed below.
1 bromine 11 lead
2 calcium 12 magnesium
3 carbon 13 manganese
4 chlorine 14 neon
5 copper 15 nitrogen
6 fluorine 16phosphorus
7 Gold 17 potassium
8 helium 18 silver
9 hydrogen 19 sodium
10 iron 20 sulfur
Part 4: Provide the name for the element corresponding to the chemical symbols below.
21 Al
22 Au
23 C
24 Ca
25 Cu
26 F
27 Fe
28 H
Week: Fifteen
Lesson: Three
Topic: Review
Part 1: Unscramble the words below to solve. Clue: Tests for gases and water
1. -GETSRIHL _________________________________________
2. DAMP RED LIMTSU EPARP _____________________________
3. DAMP ULBE UTSMIL PARPE ____________________________
4. YLCY/OLMDKIU ______________________________________
5. CIROLENH __________________________________________
6. IMNAMOA ___________________________________________
7. LMLSE _____________________________________________
8. EYOXNG ____________________________________________
9. YUKESAQ PPO _______________________________________
10. NRBCOA IIOXEDD ____________________________________
11. YDNHREGO __________________________________________
Part 2: Complete the Venn diagram by filling in the notes in the correct places.
Complete the table below
Bases Uses in the Home/Industries
Sodium Hydroxide
Potassium Hydroxide
Calcium Hydroxide
Ammonium Hydroxide
Part 3: Circle the correct answer to the questions below.
11. Carbon is considered an element while carbon dioxide is considered a compound. This is
because carbon dioxide is
A. a gas at room temperature
B. given off by plants
C. a mixture of two elements
D. a mixture of two compounds
12. Which statement best describes an element?
A. made from a mixture
B. thousands are found
C. can be separated
D. pure, made of only one atom
13. Water is an example of
A. element
B. compound
C. solution
D. none of the above
14. When two or more elements chemically combined, is formed
A. element
B. compound
C. mixture
D. solution
15. Compounds are different from elements because compounds are
A. a combination of two or more elements
B. made of the same type of atoms
C. not able to be broken down into parts
D. pure substances
16. The smallest particle of any particular type of matter is known by which of the following
terms?
A. element
B. atoms
C. compounds
D. substance
17. The picture below represents which of the following
A. an element
B. a compound
C. solution
D. none of the above
18. Which of the following is likely to be represented by the picture above
A. H2O
B. HCL
C. CH4
D. O2
19. A molecule is defined as the smallest part of an element or compound that can exist on its
own. Which one of the following is not a molecule?
A. Sodium (Na)
B. Water (H2O)
C. Hydrogen (H2)
D. Sodium chloride (NaCl)
20. Which one of the following four statements is correct?
A. The symbol for sodium is So.
B. Water is an element made up of hydrogen and oxygen atoms.
C. Compounds always contain different types of atoms.
D. All gases are elements.
Complete the crossword puzzles below.
Particle Theory of Matter
1
2
3 4
5
6
7
8
9
10 11
12
13
14
15 16
17
18
19
Across
2. Anything that takes up space and has mass
3. The ability to do work
7. How fast a solute will dissolve in a solvent.
9. A mixture where particles of each component
substance are not evenly dispersed.
10. The energy that flows from a warmer
substance to a cooler substance.
11. The transfer of heat through special waves
Down
1. A measure of the energy contained within a
substance.
4. A mixture where particles of each component
substance are evenly dispersed.
5. Matter consisting of only one type of particle
6. Is an explanation for why things work or how
things happen and are based on observations of
the world around us that are then tested.
13. The amount of solute that will dissolve in a
solvent.
15. The transfer of heat energy through solids.
16. The amount of particles in a substance
18. A homogeneous mixture composed of two
or more substances.
19. The transfer of heat energy in liquids and
gases
8. A mixture where individual particles can be
identified
12. A substance that is dissolved in a solvent.
14. The substance that the solute is dissolved in.
17. Matter consisting of more than one type of
particle