introduction to science j. stevens 2014 holt mcdougal florida physical science

Introduction to Science

J. Stevens2014

Holt McDougal Florida Physical Science

Term or concept Meaning Example

Science Study of the natural world

There are different kinds of sciences (biological, physical, earth and behavioral)

Technology application of science for practical uses

Engineering, computers

Model representation of an object or event that can be studied to understand the real object or event

Atomic model, weather model, building models, planetary models

Theory Explanation that is supported by a wide range of evidence

Theory of Relativity, Theory of plate tectonics, Theory of evolution

Scientific Law Truth valid everywhere in the universe; doesn’t provide explanations

Law of Gravity, Newton’s 3 Laws of Motion, Laws of Thermodynamics

Vocab Introduction – Section 1


Critical Thinking ask questions, make observations, use logic

Buy 2 small drinks, or 1 large?

Scientific Method Way to organize thinking Generally follows 7 steps

Observation Using the senses to study the world.

Isaac Newton noticed that apples fall to the ground.

Data Information gathered. Qualitative or quantitative

Qualitative- descriptions like behaviors, smells, etc.

Quantitative- numbers- 92 natural elements

Hypothesis Proposed answer for a scientific question, based on previous observation or knowledge. Must be testable!!

If a person runs outside when it is more than 80 degrees, they will start sweating.

Experiment Study factors / variables to find the cause / effect relationships

Independent, dependent, or control variables


Term or concept

Meaning Example

Variable Factor that can affect an experiment

Only one variable should be tested at a time

Independent Variable

The variable that is manipulated or changed by the experimenter.

Location of plants:-window sill-Table-greenhouse

Dependent Variable

Observed and measured during an experiment = the experimental data

-plant height-Number of leaves

Constant The conditions that stay the same. They never change.

Each plant is given a 1/4 cup of water each day.

Control A reference point, the normal

Plant given regular water instead of salt water



Metric System Standard, worldwide system of measurement

Meters, grams, liters

Length Distance between 2 points

100 meters to the light

Mass Amount of matter in an object

a golf ball has more mass than a ping pong ball even though they are the same size

Volume amount of space contained in an object.

A 2Liter soda

Density how much something of a set volume weighs

A lead ball the same size as a rubber ball, is more dense.

Weight measure of the force of gravity on an object.

You weigh less on the moon than earth, but have the same mass.


Term or concept

Meaning Example

Precision The exactness of a measurement

4.11m is more precise than 4.1

Accuracy Description of how close a measurement is to the true value of the quantity measured

If a measuring tape has a broken tip, the measured value will not be accurate

Scientific Notation

We express very large or very small numbers as simple numbers, multiplied by a power of 10.

1.Large number 300,000,000 = 3.0*108

2. Small number .000003 = 3.0*10-5

Significant Figure

Helps determine the amount of rounding needed to show the precision of the measurement

You multiply 8.871 * 9.14 (dimensions of a room you are painting). The answer is 81.08094. Do you need all these numbers? No. Only as many as the least precise # you used, 9.14, so 3 digits. Round to 81.1


Key Ideas and Vocab Section 1

• Key Ideas:– How do scientists explore the world?– How are the many types of science organized?– What are scientific theories, and how are they

different from scientific laws?– What are scientific models and how are they

used?• Vocabulary:

– Science - Law– Technology - Theory– Model

What is science?

• A method for studying the natural world

• Nature follows rules, and science is a method to understand those rules, and how and why they work.

• It is a process that uses observation (using your senses to gather information) and investigation to gain knowledge about events in nature

Science is not….

• a way to explain supernatural, aesthetic, or other ways of knowing, such as art, philosophy, or religion

• Pseudoscience is a claim, belief, or practice which is presented as scientific, but does not adhere to strict standards of science (e.g. controlled variables, sample size, replicability, empirical and measurable evidence, and the concept of falsification). Example: astrology

Why do we do science?• When you have a question about

something, how something works…how do you find the answer? – Research, Perform experiments using

careful, methodical study, observe, confirm.

• Scientists perform experiments to:– Find new aspects of the natural world– Explain a known phenomenon– Check the results of other experiments– Test predictions of current theories.

How science takes place

How Science

Takes Place

Scientists plan experiments

Scientists observe

Scientists answer questions by investigating/research

Scientists always confirm results

Example: Who invented the wheel…and how?

• What do you enjoy now, that you wouldn’t have without the invention of the wheel?

http://library.thinkquest.org/C004203/science/science02.htm



Example: Who invented the light bulb and how?

• What do you enjoy now, that you wouldn’t have without the invention of the light bulb? How would your light be different? How has the light bulb evolved?

Example: Who invented the telephone and how?

• What do you enjoy now, that you wouldn’t have without the invention of the telephone? How would your light be different? How has the telephone evolved?

Branches of Science

• Science: observing, studying and experimenting to find the nature of things.

• 2 main branches: – Social science (individual and group

behavior) • Examples: ________________

– Natural science (nature of the universe)

Natural Science

Natural Science

Biological Science:

Science of living things

Botany

Ecology

Zoology Many other

branches

Physical Science:

Science of matter and

energy

Physics: forces and

energy

Chemistry: matter and its changes

Earth and Space Science: Science of the

Earth and space

Geology

Astronomy

Meteorology

Many other

branches

Branches of science work together

• Today, the branches of science have become more mixed.– What do you call someone who studies

the chemistry of living things?• Biochemist

– What do you call someone who studies the physics of the Earth?

• Geophysicist

What is the difference between science and

technology?• Pure science: experiments done to

learn more about the world.• Technology: application of science for

practical uses (for example engineering)– Ex: Revelations in science have allowed

computers that used to fill entire rooms to smaller, faster, and cheaper computers.

Scientific Law• Law: describes a process in nature that can be tested

by repeated experiments; allows predictions to be made about how a system will behave under a wide range of conditions; observation of nature; valid everywhere in the universe– Describe HOW something works– Ex: if I place a hot cooking pot in a colder place,

will the pot get hotter? No! It will always get cooler, because there is a scientific LAW that says warm objects will always become cooler when placed in cooler surroundings.

– Can often be described using a mathematical formula

– Area of a rectangle: A = l*w– Universal Gravitation: F = G m1*m2 / r2

Theory• Theory: explanation of how a natural process

works; explains many related observations and is supported by a large body of evidence– Explains WHY something happens– Starts as a hypothesis– Can be added to or disproven, if new evidence

is validated and contradicts old theory– Ex: In the cooking pot example, nothing

explains WHY hot objects become cooler in cooler surroundings. This explanation must be provided by a scientific theory.

Theory• Always being questioned and

examined –CAN CHANGE!! Law does not!– Theories do not become laws, and laws

do not become theories!

• To be valid, theories must continue to pass a series of tests.– Must explain observations clearly and

consistently– Experiments that illustrate the theory

must be repeatable.– You must be able to predict results from

the theory.

Models

• Model: a representation of an object or event that can be studied to understand the real object or event

• Why? Sometimes models represent things that are too big, too small, or too complex to study easily.

• Outcome of models depend on the information put into them.

• Some examples of models:– DNA– Atoms– Weather– Buildings

• What is an example you can think of?

Section 1 Review1. Compare the two branches of physical science.2. Explain how science and technology depend on

each other and how they differ from each other.3. Define scientific law and give an example.4. Compare a scientific law and a scientific theory.5. Explain why a scientific theory might be changed.6. Describe how a scientific model is used and give

an example of a scientific model.7. Quiz next class!!


• Key Ideas:– How can I think and act like a scientist?– How can I design my own experiment?– How do scientists measure things?

• Vocabulary:– Critical Thinking - Scientific Methods– Length - Variable– Mass - Volume– Density - Weight– Metric System

Science Skills

• Identify problems• Plan experiments• Record observations• Report data• Critical thinking – ask questions, make

observations, use logic – large or small popcorn

• Creative thinking – to identify questions/problems, imagine and test solutions, be creative in the approach to solving problems

Problem Solving/ Critical Thinking Activity

Scientific Method• A general way to organize your thinking about

questions• A series of steps followed to solve problems• 7 Basic Steps of the Scientific Method1. Make an observation2. Ask a question (what’s the problem you want to

figure out?) / Research3. Form a hypothesis4. Test your hypothesis - Experimentation5. Collect data / Results6. Analyze and Conclude7. Repeat

Scientific Method

Observe

Ask a question/

Conduct

research

Form a hypothe

sis

Test your hypothesis (Experime

nt)

Collect Data/Result

s

Analyze and

Conclude

Repeat

Observe anything in nature

What do you want to know?What is already known about your question

Propose an answer to your question based on observations, research, and data.

Plan and perform an experiment.

Hypothesis must be testable!!!

Results must be repeatable to be valid.

Organize data, i.e. use a table.

Put data in useable form, graphs. Make Conclusion. Did data support your hypothesis?

Step 1: Observation

• Use senses to study the world. Can also use tools such as previous research and computers.

Observation

Definition: uses senses to study the world (see, hear, smell, taste, feel). Can also use tools like computers.

Facts: 1. observations describe something using my senses. 2. observations can be made using tools like computers.

Example: 1. The apple is red.2. The apple feels soft

Sentence:I made the observation that the apple is red, by using my sight.

Inference• Inference: logical interpretation based on prior

knowledge and past experiences. An explanation for an observation you have made.

• Inferences are often changed when new observations are made.

• Usually has the word “because” in it.

Inference

Definition: logical interpretation based on knowledge and past experiences.

Facts:

Example: Sentence:

Observation vs. Inference

• Observation: using the sense of sight and touch, I observe that:– The grass on the front lawn is wet

• Why could it be wet?

Possible Inferences

• It rained.• The sprinkler was on.• There is dew on the grass from the

morning. • A dog urinated on the grass!

All of these inferences could possibly explain why the grass is wet. They are all based on prior experiences. We have all seen rain, sprinklers, morning dew, and dogs going to the bathroom.

Observation

• The Fire Alarm is going off.• Why is this an observation?

• Make an inference…

Possible Inferences

• Fire• Fire Drill • Student pulled the alarm to avoid a

test

Step 2:

• Ask a question: Based on your observation, what do you want to know.

• Conduct research: figure out what is already known about your problem.

• Example: – Observation: My dog is a picky eater.– Question: Which type of food do picky dogs like best?– Research: conduct research (computer based, interviews,

journals) about what picky dogs like to eat.

Step 3: • Form a hypothesis.

– A hypothesis is a prediction of what you think will happen, based on prior knowledge and the research you have conducted.

– Must be testable!!!!– Example:

• Hypothesis: If I give my dog chicken flavored dog food, beef flavored dog food and duck flavored dog food, then she will eat the duck flavored dog food most of the time because research has shown that duck flavored dog food has a stronger smell.

– In your hypothesis, you MUST state why you believe that is what will happen.

Step 4: • Test your hypothesis by doing a controlled

experiment.• Materials – What do you need to conduct your

experiment?• Procedure – sketch / step by step instructions of

how you conduct your experiment so it can be repeated by someone who knows nothing about it

• What would your materials and procedures be for the dog experiment?

• In your experiment, you will have different variables.

• A variable is a factor that changes in an experiment in order to test a hypothesis

Step 4 continued: • Four different kinds of variables (factors)

– Dependent variable: what you are measuring– Independent variable: what you, the

experimenter, change– Constant: what stays the same throughout– Control Group: the normal

• Variables that can affect the outcome of the experiment are kept constant, except the one(s) you want to measure. The more things you change at a time, the harder it is to make reliable conclusions.

• Dog example: – Dependent variable? - Constants?– Independent variable? - Control Group?

Another example

• You might set up an experiment to determine which of three fertilizers helps plants to grow the biggest.

• Possible factors include plant type, amount of sunlight, amount of water, room temperature, type of soil, and type of fertilizer.

Variables

• In this experiment, the amount of growth is the dependent variable because its value changes according to the changes in the other variables.

PlantAmount of

WaterAmount of Sun

Fertilizer Type

Height after two weeks

A4 oz. every three days 6hr/day A 16cm

B4 oz. every three days 6hr/day B 14cm

C4 oz. every three days 6hr/day C 18cm

D4 oz. every three days 6hr/day none 10cm

Variables• The variable you change to see how it

will affect the dependent variable is called the independent variable. What is the independent variable?

PlantAmount of

WaterAmount of

SunFertilizer

TypeHeight after two weeks





Constants and Controls

• A factor that does not change when other variables change is called a constant.

• You might set up four trials, using the same soil and type of plant.

• Each plant is given the same amount of sunlight and water and is kept at the same temperature. These are constants.


• The fourth plant is not fertilized• This plant is a control. A control is

the standard by which the test results can be compared -- neutral point of reference for comparison

PlantAmount of

WaterAmount of

SunFertilizer

TypeHeight after two weeks






• Suppose that after several days, the three fertilized plants grow between 2 and 3 cm.

PlantAmount of

WaterAmount of Sun

Fertilizer Type

Height after two weeks






• If the unfertilized plant grows 1.5 cm, you might infer that the growth of the fertilized plants was due to the fertilizers. The control is the plant that was unfertilized.

• Scientific Variables.mp4

PlantAmount of

WaterAmount of Sun

Fertilizer Type

Height after two

weeks





Step 5: • Collect Data/Results

– Need to organize data in a meaningful way.– A table, excel spreadsheet, graph or database are

examples.– There are two different types of data, both of value

• Quantitative Data: “quantity”; data that is measureable or countable; observations that use numbers; USUALLY what we use in science– The tree is 20 feet and 7 inches tall.– The wind is blowing at 50 mph.

• Qualitative Data: “quality”; descriptions using your senses. Use adjectives to describe something.– The tree is tall.– The wind is blowing hard.

• Write three of your own examples for each.

Quantitative or Qualitative??

1. When the chemicals combined a gas formed. _______________

2. The ph remained neutral at 7._______________3. 95 degrees Farenheit= _______________________4. The waves were big= ________________________5. The sky is blue = __________________________6. I am 5’ 7” tall=__________________________7. It took 20 minutes to drive to school____________8. Prarie dogs are very social creatures=___________9. I slept for 7 hours______________10.The blanket feels soft and fluffy_______________

Answers1. Qualitative2. Quantitative3. Quantitative4. Qualitative5. Qualitative6. Quantitative7. Quantitative8. Qualitative9. Quantitative10.Qualitative

Step 6: Analyze and Draw Conclusions

• Based on the analysis of your data, you decide whether or not your hypothesis is supported.

• For the hypothesis to be considered valid and widely accepted, the experiment must result in the exact same data every time it is repeated.

• What if your hypothesis is wrong?– Try again, revamp your procedure / experiment.

Step 7

• Repeat the experiment.• To be valid, the results must be

repeatable!

Being Objective

• Everyone has bias. Bias can happen due to many things: environment growing up, belief system, funding, etc.

• A bias occurs when what the scientist expects, changes how the results are viewed.

• This expectation might cause a scientist to select a result from one trial over those from other trials.

• Scientists can lessen bias by running as many trials as possible and by keeping accurate notes of each observation made.

Being Objective

• Valid experiments also must have data that are measurable.

• The experiment must be repeatable.• Findings are supportable when other

scientists perform the same experiment and get the same results.

1. Scientists observe nature, then develop or revise hypotheses about how things work.

2. The hypotheses are tested against evidence collected from observations and experiments.

3. Any hypothesis that correctly accounts for all of the evidence from the observations and experiments is a potentially correct theory.

4. A theory is continually tested by collecting new and different evidence. Even one piece of evidence that does not agree with a theory forces scientists to return to step one.

5. Mr. Lee - Scientific Method song.mp4

Recap: Scientific Method – how it works

Scientists use special tools

• What would an astronomer use to study distant galaxies?

• Physicists use particle accelerators to make parts of atoms move very fast.

• Biologists use microscopes to study very small organisms and cells.

Pick A Question and Design an Experiment1. Will human urine repel sharks?

2. Does the color red make lizards more aggressive?

3. Will fish grow larger if placed in a larger tank?

4. Does exercise reduce your risk of heart attack?

5. Does aspirin keep cut flowers fresh longer?

*** Remember, must include question, hypothesis (so need to do research), materials, procedure (step by step of how the experiment will be performed-including variables- and how data will be collected.)

Length, Mass and Volume

T. Trimpe 2008 http://sciencespot.net/

How do scientists measure things?

• Math is the language of science.

• So everyone is on the same page, scientists use standard units of measure

• We use the SI (International System of Units) to be consistent all over the world.

• Example: if you drink 3 gallons of water per week, and your friend drinks 350 ounces, who drinks more water?

– 128 oz in 1 gallon

Some Base Units

Quantity Unit Abbreviation

Length Meter m

Mass Kilogram kg

Time Second s

Volume Liter L

Temperature

Kelvin K

Discovery News

http://news.discovery.com/tech/videos/time-to-switch-to-the-metric-system-130827.htm

SI Prefixes• Look at a ruler. How would you express the

length of a bird’s egg, or the distance you travelled on a road trip in meters?– Bird’s egg may be 5/10ths of a meter

or .05m– Road trip may be 800,000m– To avoid long numbers and lots of decimals

we use prefixes for small and large numbers.

– All prefixes are in multiples of 10

SI PrefixesPrefixes for LARGE measurements

Prefix Symbol Meaning Multiple of base unit

Kilo- k Thousand 1,000

Mega- M Million 1,000,000

Giga- G Billion 1,000,000,000Prefixes for SMALL measurements

Prefix Symbol Meaning Multiple of base unit

Deci- d Tenth .1

Centi- c Hundredth .01

Milli- m Thousandth .001

Micro- µ Millionth .000001

Nano- n Billionth .000000001

So, for example 1 meter = 100 centimeters= 1000 millimeters

Converting SI Units• The width of a soccer goal is 7m. What

is the width of the goal in centimeters?• Given: length in meters(l) = 7• Unknown: length in centimeters = ? Cm• Plan: we know from chart that

1m=100cm• Solve: length in cm = 7m * (100cm/1m)• Answer = ?• I will show you another way to do this

later.

Length

• Length is the distance between two points.

• The SI base unit for length is the meter.

• We use rulers or meter sticks to find the length of objects.

copyright cmassengale

Mass• Mass is the amount of matter

that makes up an object.• A golf ball and a ping pong ball

are the same size, but the golf ball has a lot more matter in it. So the golf ball will have more mass.

• The SI unit for mass is the gram.• A paper clip has a mass of about

one gram.• The mass of an object will not

change unless we add or subtract matter from it.


Measuring Mass• We will use a triple beam balance

scale to measure mass.• Gravity pulls equally on both sides of

a balance scale, so you will get the same mass no matter what planet you are on.


Weight

• Weight is a measure of the force of gravity on an object.

• Your weight can change depending on the force of gravity. The gravity will change depending on the planet you are on.

• The SI unit for weight is the Newton (N).

• The English unit for weight is the pound. copyright cmassengale

Mass vs. WeightMass

• a measure of how much matter an object is made of

• does not change, regardless of where something or someone is

Weight

• the force of gravity on an object

• equal to the mass of the body times the local acceleration of gravity

http://www.exploratorium.edu/ronh/weight/index.html

Why do you think

the person’s weight is

less on the moon?

Mass = 59 kg Mass = 59 kg

Weight = 579 N Weight = 96 N

http://www.exploratorium.edu/ronh/weight/index.html

Volume• Volume is the

amount of space contained in an object.

• We can find the volume of box shapes by the formula Volume = length x width x height

• In this case the units would be cubic centimeters (cm3).

• So a box 2 cm x 3 cm x 5cm would have a volume of 30 cm3

V = L x W x Hcopyright cmassengale

Base Units

• The base unit for volume is the Liter.

• We measure volume with a graduated cylinder.


Graduated Cylinders

• Liquids form curved, upper surfaces when poured into graduated cylinders

• To correctly read the volume, read the bottom of the curve called the meniscus


Water Displacement

• We can use water displacement to find the volume of objects that are not boxed shaped.

• We can put water in a graduated cylinder. If a rock causes the level to rise from 7 to 9 ml, the the rock must have a volume of 2-mL.


English vs. Metric Units


Length: English vs. Metric Units

Left Image: http://webapps.lsa.umich.edu/physics/demolab/controls/imagedemosm.aspx?picid=1167Right Image: http://share.lancealan.com/N800%20ruler.jpg

Which is longer?

A. 1 mile or 1 kilometer

B. 1 yard or 1 meter

C. 1 inch or 1 centimeter

1.6 kilometers

1 mile

1 yard = 0.9444 meters

1 inch = 2.54 centimeters

Metric Units

The basic unit of length in the metric system in the meter and is represented by a lowercase m.

Standard: The distance traveled by light in absolute vacuum in 1⁄299,792,458 of a second.

Metric Units

1 Kilometer (km) = 1000 meters

1 Meter = 100 Centimeters (cm)

1 Meter = 1000 Millimeters (mm)

Which is larger?

A. 1 meter or 105 centimeters

B. 4 kilometers or 4400 meters

C. 12 centimeters or 102 millimeters

D. 1200 millimeters or 1 meter

Measuring Length

Ruler: http://www.k12math.com/math-concepts/measurement/ruler-cm.jpg

How many millimeters are in 1 centimeter?

What is the length of the line in centimeters? _______cm

What is the length of the line in millimeters? _______mm

What is the actual length of the line? _____________ cm

What is the length of the line to the nearest centimeter? ________cm

HINT: Round to the nearest centimeter – no decimals.

1 centimeter = 10 millimeters

Weight and MassJill Earth

1 gravity

Moon1/6th

gravity

Jupiter2.5

gravities

On orbit0

gravity

mass 30kg 30kg 30kg 30kg

weight 300N 50N 750N 0 Newton

s• Notice that Jill’s mass never changes. We cannot

add to her or take away from her, so her mass stays the same. Jill is 30kg of little girl no matter where she goes!

• Her weight does change, because weight depends on gravity!!

• 10 N = 2.25 lbs. copyright cmassengale

Gravity

• Gravity is the force of attraction between any two objects with mass.

• The force depends on two things: distance and mass

• more distance = less gravity = less weight• less distance = more gravity = more

weight• more mass = more gravity = more weight• less mass = less gravity = less weight


Mass: English vs. Metric Units

Which is larger?

1. 1 Pound or 100 Grams

2. 1 Kilogram or 1 Pound

3. 1 Ounce or 1000 Milligrams

1 pound = 453.6 grams

100 kilogram = 220 pounds

1 ounce of gold = 28,349.5 milligrams

Metric Units

Mass refers to the amount of matter in an object.

The base unit of mass in the metric system in the kilogram and is represented by kg.

Standard: 1 kilogram is equal to the mass of the International Prototype Kilogram (IPK), a platinum-iridium cylinder kept by the BIPM at Sèvres, France.

Metric Units

1 Kilogram (kg) = 1000 Grams (g)

1 Gram (g) = 1000 Milligrams (mg)

Which is larger?

A. 1 kilogram or 1500 grams

B. 1200 milligrams or 1 gram

C. 12 milligrams or 12 kilograms

D. 4 kilograms or 4500 grams

Kilogram Prototype

Kilogram Prototype Image - http://en.wikipedia.org/wiki/Kilogram

Measuring Mass

Top Image: http://www.southwestscales.com/Ohaus_Triple_Beam_750-SO.jpgBottom Image: http://www.regentsprep.org/Regents/biology/units/laboratory/graphics/triplebeambalance.jpg

We will be using triple-beam balances to find the mass of various objects.

The objects are placed on the scale and then you move the weights on the beams until you get the lines on the right-side of the scale to match up.

Once you have balanced the scale, you add up the amounts on each beam to find the total mass.

What would be the mass of the object measured in the picture?

_______ + ______ + _______ = ________ g

Measuring Mass – Triple-Beam Balance

1st – Place the film canister on the scale.

2nd – Slide the large weight to the right until the arm drops below the line. Move the rider back one groove. Make sure it “locks” into place.

3rd – Repeat this process with the top weight. When the arm moves below the line, back it up one groove.

4th – Slide the small weight on the front beam until the lines match up.

5th – Add the amounts on each beam to find the total mass to the nearest tenth of a gram.

Volume: English vs. Metric Units

Which is larger?

A. 1 liter or 1 gallon

B. 1 liter or 1 quart

C. 1 milliliter or 1 fluid ounce

1 gallon = 3.79 liters

It would take approximately 3 ¾ 1-liter bottles to equal a gallon.

1 fl oz = 29.573 ml

1 12-oz can of soda would equal

approximately 355 ml.

1 quart = 0.946 liters

Metric Units

Volume is the amount of space an object takes up.

The base unit of volume in the metric system in the liter and is represented by L or l.

Standard: 1 liter is equal to one cubic decimeter

Metric Units

1 liter (L) = 1000 milliliters (mL)

1 milliliter (mL) = 1 cm3 (or cc) = 1 gram*

Which is larger?

A. 1 liter or 1500 milliliters

B. 200 milliliters or 1.2 liters

C. 12 cm3 or 1.2 milliliters*

Click the image to watch a short video

about volume.

* When referring to waterLiter Image: http://www.dmturner.org/Teacher/Pictures/liter.gif

http://www.metricamerica.com/SI-Metric/liter.wmv

Measuring Volume

Top Image: http://www.tea.state.tx.us/student.assessment/resources/online/2006/grade8/science/images/20graphicaa.gifBottom Image: http://morrisonlabs.com/meniscus.htm

We will be using graduated cylinders to find the volume of liquids and other objects.

Read the measurement based on the bottom of the meniscus or curve. When using a real cylinder, make sure you are eye-level with the level of the water.

What is the volume of water in the cylinder? _____mL

What causes the meniscus?

A concave meniscus occurs when the molecules of the liquid attract those of the container. The glass attracts the water on the sides.

Measuring Liquid Volume

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Pay attention to the scales for each cylinder.

Measuring Solid Volume

10 cm

9 cm

8 cm

We can measure the volume of regular object using the formula length x width x height.

_____ X _____ X _____ = _____

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We can measure the volume of irregular object using water displacement.

Amount of H2O with object = ______

About of H2O without object = ______

Difference = Volume = ______

Density• Density is the mass per unit volume of a material

or how much something of a set volume weighs

• Some things weigh more than others even though they take up the same space…so, lead is much more dense than foam or wood.

• Formula:

http://www.green-planet-solar-energy.com/definition-of-density.html



Metric Conversions Ladder Method


KILO1000Units

HECTO100

Units

DEKA10

UnitsDECI

0.1Unit

CENTI0.01Unit

MILLI0.001Unit

MetersLitersGrams

Ladder Method

How do you use the “ladder” method?

1st – Determine your starting point.

2nd – Count the “jumps” to your ending point.

3rd – Move the decimal the same number of jumps in the same direction.

4 km = _________ m

12

3

How many jumps does it take?

Starting Point Ending Point

4.1

__.2

__.3

__. = 4000 m

What properties should I measure? (length, mass, volume or weight)? What units?

Review and Practice Section 2

• Metric Mania worksheet• Simpsons scientific method• Sponge Bob scientific method


• Key Ideas:– Why is organizing data an important science

skill?– How do scientists handle very large and very

small numbers?– How can you tell the precision of a

measurement?• Vocabulary:

– Precision– Accuracy– Scientific Notation– Significant Figure

Organizing Data

• How would you organize data you are collecting?

• Example: You want to determine the average height of people in your class. How do you collect & organize the data?Name Height in inches

Sue 62

Jason 72

Jack 70

Melissa 67

Average ?

Why is it important?

• Keep track of data (what if you have thousands of people who’s height you are tracking?)

• Be able to analyze the data and refer to it later.

• Share results with written reports and oral presentations.

Presenting Data• Graphs are a great way to present data, but there are

many kinds, each for a specific kind of data.• ***Always, always title and label your graphs!!!1. Line graphs

– Show continuous change– Show something over time– Dependent variable on y-axis– Independent variable on x-axis

Presenting Data

2. Bar Graphs– Useful when you want to compare similar type data

for several individual items or events.– Used when you are comparing qualitative vs

quantitative data

Presenting Data

3. Pie Graphs– Show the parts of a whole– Shows percentages– Percentages should = 100% (parts of a whole)

Presenting Data

4. Histogram– Show the frequency distribution of the data.– The bars touch!– Ex- using the numbers make a data table and

histogram in your notes.• 7, 12, 12, 18, 22, 24, 26, 27, 28, 29, 31, 36, 36,

39, 43, 47

Scientific Notation• Sometimes, numbers are too small or too large to

write out.• The speed of light is ~300,000,000 m/s• How long does it take for light to get from Neptune

to Earth (4,5000,000,000,000 m away)?• Looking for time. t = d/s• There are way too many zeros! • We can express these as simple numbers,

multiplied by a power of 10. • Another way to write the speed of light is 3.0*108

m/s, and distance from Neptune, 4.5*1012 m.• For small numbers, .001 would be written as 10-3

Precision and Accuracy

• Precision: the exactness of a measurement– If you are measuring the distance of two long jumps and are using a

tape measure marked every .1m, you could report that both measurements were 4.1m. But if your tape measure marked every .01m, you could get more precise values. One jump was 4.11m and one was 4.14.

• Accuracy: Description of how close a measurement is to the true value of the quantity measured– If, when measuring the long jump, you notice that the tip of the

measuring tape is broken, you could still show 4.14m, but its not accurate. A measurement is only as accurate and precise as the tool used to make it.

• Significant Figures: Helps determine the amount of rounding needed to show the precision of the measurement– The distance of 4.1m has two significant figures because the measured

value has 2 digits. 4.14, 3 significant figures, because of 3 digits. Rule of thumb: when answering a problem, your answer should have as many significant figures as the number in your problem with the least amount of digits.

Practice – Section 3• Round the following to

two significant digits:1. 13,5892. 8893. .0002419494. .725

• Answers:1. 14,0002. 8903. .000244. .73

1. Crumple 5 pieces of paper

2. Throw them into a trash bin ~2m away.

3. Move the trash 2 more meters away and throw the pieces of paper in.

4. How accurate were your throws at 2m? Precise?

5. Were your accuracy and precision better or worse, when the bin was moved farther?

Test Coming Up

• Review your notes• Study your vocabulary• Prepare yourself!!!

• Note packet due on Test Day!!!

introduction to science j. stevens 2014 holt mcdougal florida physical science

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