Physics 1EnergyPPT. by, Robin D. Seamon

MOTION

•Position: the location of an object

•Direction: N, S, E, W

•Speed: distance over time (tells how fast it moved)

EXAMPLE: the soccer ball moved 20m east.

Did it move 20m in 2 sec? OR

Did it move 20m in 2 min?

Which is the slower speed?

How do you measure motion?

•Stopwatch

•Divide: distance time

QUESTIONS:

1. What is the speed of the golf ball that moves 35 m in 5 sec?

2. Why is a compass a useful tool to describe motion?

3. How can motion be described?

FORCE & MOTION

•Force: a push or pull on an object

The amount of force you apply, determines how fast the object will move

If an object stops, speeds up, slows down, or changes direction, a force has been applied to it!

EXAMPLES: gravity, lift, thrust, friction

EXAMPLE: Forces on a Shark

Thrust

Lift

Drag : air/water resistance

Describe the force the weight lifter is exerting on the bar. Are the forces balanced or unbalanced?

PRACTICE LINK

PRACTICE Q’s

Hydraulic Lift simulation

Activity 1

Quiz 2

Energy & Machines

•Energy: the ability to do work (joules)(amt. of E to lift an apple 1m)

•Machine: something that replaces human effort

•Friction: the force that slows down or stops motion

•Gravity: the fore that pulls all objects on Earth toward the center of Earth (All objects have gravity; the larger the object, the stronger the gravitational pull)

•Potential Energy: stored up Energy; energy ready to be used

•Kinetic Energy: energy of motion; WORKING Energy mv2

2

M= mass kg; v= speed

FORMS of ENERGY:

•Thermal energy: energy from the rapid movement of molecules, causing heat- high temp to low temp-moves faster at high temp

•Mechanical energy: Energy of motion & position-stays the same unless transfers to another object

•Electrical energy: energy from moving electrons in atoms (negative charge around atoms)

•Gravitational potential energy: potential energy an object has if it falls

•Elastic Potential energy: potential energy of an object as it is forced to change shape, but has the ability to return to its normal shape.

•Chemical energy: energy from the interaction of molecules

•photosynthesis sugar forms by work of joining different atoms together in certain patterns: C6 H10 O2

•burning wood releases E as heat

•explosion rapid release of E

•Nuclear energy: energy that comes from changes in the nucleus of an atom

•Fission break apart (power plants)

•Fusion put together (sun)100,000,000°C: H joins to form He

•Light energy: energy from light; vibrations of electrically charged particles (NOTE: do not need air to transmit… can transmit through a vacuum as photons)

•Sound energy: energy from sound waves; objects vibrate, transmitting some of the kinetic E to air around it, air particles vibrate & transmit E to your ear… YOU HEAR!

SIR ISAAC NEWTON: (1643-1727) Mathematician & astronomer

NEWTON LINK BIOGRAPHY

•Newton’s 1st law of Motion: objects remain still or in motion until another force is applied to it (law of inertia)

•Newton’s 2nd law of Motion: acceleration happens when a force is acted on an object. The greater the mass of the object, the more force is needed to move it. (f=ma)

•Newton’s 3rd law of Motion: for every action, there is an equal and opposite reaction

•NEWTON LINK: explore the 3 laws

http://www.mrdowling.com/601-newton.html

ENERGY CONVERSIONS:(changing from one form to another)

Elastic potential Energy

Chemical energy of food you eat: atoms rearrange to make energy for you

Energy pyramid

Light E > chemical E > we eat it > to kinetic E as we move & live

ENERGY CONVERSION LABMake a list of 15-20 gadgets. Denote the source of E and

into what kind of E it converts

GADGET SOURCE DESTINATION

Alarm clock Electrical E Light & sound E

Battery Chemical E Electrical E

Light bulb Electrical E Light & thermal E

Blender Electrical E Kinetic & sound E

ENERGY CONVERSION LABMake a list of 15-20 gadgets. Denote the source of E and

into what kind of E it converts

ENERGY CONVERSION LABMake a list of 15-20 gadgets. Denote the source of E and

into what kind of E it converts

ENERGY CONVERSION LABMake a list of 15-20 gadgets. Denote the source of E and

into what kind of E it converts

ENERGY CONVERSION LABMake a list of 15-20 gadgets. Denote the source of E and

into what kind of E it converts

ENERGY CONVERSION LAB 2

Choose one daily activity that you do. Trace the Energy back as far as

you can go.Soccer ball moves (mechanical Energy) > Kicking a soccer ball (mechanical Energy) > muscles move forward (mechanical Energy) > Energy goes to my muscles from food I eat > (chemical Energy) > the bacon I ate has Energy from the plants the pig ate (chemical Energy) > the plant has Energy from the sun (photosynthesis/light Energy) > the sun gives off light Energy from nuclear fusion > nuclear fusion comes from the combining of hydrogen atoms to make helium…

All machines require energy to work. Which source makes the most sense for the job?

QUESTIONS:

1. What is needed to operate a machine?

2. What is a device that replaces human effort?

3. Why does a machine that lifts boxes off the ground need energy?

Unbalanced Forces & Motion•Balanced Forces: forces that have equal measure & are balanced; net force of zero

•Unbalanced Forces: forces in which one is greater (stronger) than the other, causing motion

No motionNo motion Object moves leftObject moves left

What affects Motion?

•Friction: a force that acts on an object to STOP the motion: ground, air, bumps

•Inertia: the tendency of an object to remain still or in motion unless acted on by a force

•Momentum: product of the mass and velocity of an object

MODELS:

• Design: imagining and creating a best way to solve a problem

1.What are the limits?

2.What materials make sense?

3. Is space a limit?

• Model: testing your design; replica; computer simulations

• Communicating: report your designs, drawings, & findings

Pulley: uses grooved wheels and a rope to raise, lower, or move a load

Simple Machine: a tool that makes work easier

Lever: a stiff bar that rests on a middle support, used to lift or move loads.

http://www.cool-science-projects.com/simple-machine-science-project.html

Wedge: has a slanted side that ends in a sharp edge. This tool concentrates the energy to that one edge/point

Wheel & axle: a wheel with a rod through its center that lifts or moves loads

http://www.msnucleus.org/membership/html/k-6/as/technology/2/images/gear.gif

Inclined plane: is a slanted surface that helps move an object up

Screw: an inclined plane that is wrapped around a pole; hold things together or lift things up

www.yourdictionary.com/screw

QUESTIONS:

1. The motion of any object can be describe by its position an how that position changes over __

2. What is a push or pull on an object called?

3. In order to work, what do all machines require?

4. What type of energy is used to move things?

5. During a tug of war, each team is pulling on the rope with equal forces in opposite directions. What is this an example of?

6. The force of friction acts in which direction?

7. After a design is found, the designer must test the design, evaluate the test, and then what?

8. A teeter-totter is an example of which kind of simple machine?

time

force

energy

mechanical energy

balanced forces

Opposite direction object is moving

Communicate it

leverBBC Forces QUIZ

Energy Efficiency:

Closed system: group of objects that only transfer E to each other. (not everything is a closed system)

*In Conversion of E, some ALWAYS gets converted to thermal E (not lost!)

Energy efficiency: comparison of the amount of E before conversion, with the amount after conversion

How can you make machines more Energy Efficient? (more useful)

•Oiling mechanical parts reduces friction & heat loss

•Aerodynamic shapes use less E to overcome friction

LAB: Energy Trace

Pick a daily activity & trace it back to its source of E

Energy Resources

•Fossil Fuels: resource from buried Carbon:burning coal, oil & natural gas

NON-RENEWABLE RESOURCE

-Steam-turbine-generator-electricity

•Nuclear Fuels: uses radioactive metals, uranium & plutonium in chemical reactions to produce heat> steam> energy

NON-RENEWABLE RESOURCE

•Solar Energy:

HEAT or ENERGY

•solar cells hold water or silicon, sun/light heats it (= hot water/spaces or electric charge from heated silicon molecule)

RENEWABLE RESOURCE

NOTES

•Water: (Hydroelectric Power) water rushes down through tubes inside the dam. The moving water drives electrical generators, which may be built inside the dam

RENEWABLE RESOURCE

•Wind Energy: using the wind to turn turbines for energy

RENEWABLE RESOURCE

•Geothermal Energy: using heat from inside the earth to warm water> steam> energy (radioactive decay of uranium= heat)

RENEWABLE RESOURCE

•Biomassorganic matter that’sburned to releaseEnergy

Burning wood; captured methane; municipal waste;agricultural residue

RENEWABLE RESOURCE

ELECTRICITY

Activities LINK QUIZ

LAB ENERGY PRO’s & CON’s

List the advantages & disadvantages of the following sources of Energy.

ENERGY TYPE ADVANTAGE DISADVANTAGE

Fossil fuels

nuclear

solar

water

Wind

Geothermal

Biomass

BBC Energy Links

HOW STUFF WORKS:

Telephone system

Wii

Radio

Helicopters

Toilets

Microwaves

LCD & Plasma tv

Light bulbs

Air & refrigeration

Electricity 1

Electricity 2

Water Treatment Plants

QUIZ