The Nature of ScienceThe Nature of ScienceChapter 1Chapter 1

Sections 1 - 3Sections 1 - 3

Chp 1 – The Nature of ScienceChp 1 – The Nature of Science

Section 1- The Methods of Science Section 1- The Methods of Science slides 3 – 28slides 3 – 28

Section 2- Standards of MeasurementSection 2- Standards of Measurement slides 29 -slides 29 -5050 Section 3 – Communicating with GraphsSection 3 – Communicating with Graphs

slides 51-67

1 – The Methods of Science1 – The Methods of Science

How scientists solve problems How scientists solve problems Why scientists use variablesWhy scientists use variables Compare and contrast science and Compare and contrast science and

technology technology

What is science?What is science?

The word The word science science comes from Latin comes from Latin meaning “knowledge.” meaning “knowledge.”

It is a way to learn by observing and It is a way to learn by observing and investigating.investigating.

Nature follows a set of rules which can be Nature follows a set of rules which can be studied through science.studied through science.

<www.time.com><www.time.com>

What are the major categories of What are the major categories of science?science?

Life Science- Life Science- Earth Science- Earth Science-

Physical Science- Physical Science-

Sometimes these three categories Sometimes these three categories overlap.overlap.

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What are the major categories of What are the major categories of science?science?

Life Science- the study of living thingsLife Science- the study of living things Earth Science- the study of Earth & outer Earth Science- the study of Earth & outer

spacespace Physical Science- the study of matter & Physical Science- the study of matter &

energyenergy Sometimes these three categories Sometimes these three categories

overlap.overlap.

How does science explain nature?How does science explain nature?

Scientists use investigations to get new Scientists use investigations to get new information about the natural world.information about the natural world.

Technology helps scientists learn more.Technology helps scientists learn more. Sometimes new info causes scientific Sometimes new info causes scientific

explanations to change.explanations to change.

What are investigations?What are investigations?

1. Observing & recording1. Observing & recording 2. Experimenting2. Experimenting 3. Building a model3. Building a model Scientists might use one or all three types Scientists might use one or all three types

of investigations to get new information of investigations to get new information about how nature works.about how nature works.

What is a variable?What is a variable? An experiment might test 3 fertilizers to An experiment might test 3 fertilizers to

see which one helps plants grow biggest. see which one helps plants grow biggest. In this experiment there are 2 variables In this experiment there are 2 variables being studied. A being studied. A variablevariable is a quantity is a quantity that can have more than one value. The that can have more than one value. The height of the plants is a variable because it height of the plants is a variable because it can have a range of values. The variable can have a range of values. The variable that is measured at the end of the that is measured at the end of the experiment is called the experiment is called the dependent dependent variable variable because it depends upon what because it depends upon what happens in the experiment.happens in the experiment.

What is a variable?What is a variable? The height of the plants is the dependent The height of the plants is the dependent

variable because that is what is measured variable because that is what is measured at the end of the experiment.at the end of the experiment.

The fertilizer is also a variable because the The fertilizer is also a variable because the researcher is using three different kinds.researcher is using three different kinds.

A variable that is controlled and changed A variable that is controlled and changed by the researcher is called the by the researcher is called the independent variableindependent variable. There should be . There should be only one independent variable in an only one independent variable in an experiment.experiment.

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Why are constants & controls Why are constants & controls important?important?

To keep an investigation fair, all other To keep an investigation fair, all other factors must remain the same for each factors must remain the same for each trial. A factor that does not change is a trial. A factor that does not change is a constant.constant.

In the fertilizer experiment, the constants In the fertilizer experiment, the constants are the amount of water & sunlight the are the amount of water & sunlight the plants get & the kind of soil they’re planted plants get & the kind of soil they’re planted in. All constants are kept the same for the in. All constants are kept the same for the three types of fertilizer tested.three types of fertilizer tested.

Why are constants & controls Why are constants & controls important?important?

Researchers use a Researchers use a control control to compare to compare the results of the experiment against. The the results of the experiment against. The control plant does not receive any fertilizer control plant does not receive any fertilizer but receives the same amount of water & but receives the same amount of water & sunlight & soil as the other plants.sunlight & soil as the other plants.

This helps scientists understand whether This helps scientists understand whether the fertilizer is having an effect on the the fertilizer is having an effect on the plants or whether they would grow that plants or whether they would grow that way in regular conditions.way in regular conditions.

Scientific MethodsScientific Methods

A set of steps used by A set of steps used by scientists in an scientists in an investigation is called investigation is called a a scientific method.scientific method. Sometimes certain Sometimes certain steps may be steps may be repeated & others repeated & others may be skipped. The may be skipped. The steps are cyclical & steps are cyclical & may be started at any may be started at any point.point.

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State the problem:State the problem:

Many investigations Many investigations begin when someone begin when someone sees something sees something happen in nature & happen in nature & wonders how or why wonders how or why it happened. it happened.

Sometimes a Sometimes a question is asked question is asked because you are because you are looking for a better looking for a better way.way.

<phyun5.ucr.edu>

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Research & Gather InformationResearch & Gather Information

Study the problem Study the problem before doing any before doing any testing. Find testing. Find information regarding information regarding similar designs or similar designs or problems. Using your problems. Using your research and what research and what you’ve observed, form you’ve observed, form a hypothesis.a hypothesis.

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Form a hypothesisForm a hypothesis

AA hypothesis hypothesis is an is an explanation for a explanation for a question or problem question or problem based on what you based on what you know & what you know & what you observe. observe.

It must be tested to It must be tested to be certain whether or be certain whether or not it works.not it works.

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Test the hypothesisTest the hypothesis

Some hypotheses are Some hypotheses are tested by making tested by making observations or by observations or by building a model. building a model. Often an experiment Often an experiment is used to test the is used to test the hypothesis. The hypothesis. The experimentexperiment looks at looks at how one thing affects how one thing affects another under another under controlled conditions.controlled conditions.<www.thwink.org/ >

Analyze DataAnalyze Data All results and observations must be All results and observations must be

recorded during an experiment. recorded during an experiment. Many important discoveries have been Many important discoveries have been

made from unexpected results. made from unexpected results. The information or The information or

data should be data should be organized into an organized into an easy-to-read table easy-to-read table or graph.or graph.

Draw ConclusionsDraw Conclusions

Scientists share their Scientists share their data with others. If the data with others. If the data supports the data supports the hypothesis and can be hypothesis and can be repeated successfully, repeated successfully, other people will other people will eventually agree with eventually agree with the conclusions. the conclusions. Sometimes data does Sometimes data does not support the original not support the original hypothesis.hypothesis.

Why must scientists be objective?Why must scientists be objective?

Bias Bias occurs in an experiment when a occurs in an experiment when a scientist expects something to happen & scientist expects something to happen & lets this influence how the results are lets this influence how the results are viewed.viewed.

Bias can be reduced by doing the Bias can be reduced by doing the experiment over many times while keeping experiment over many times while keeping careful notes. Other scientists repeat the careful notes. Other scientists repeat the same experiment to see if they get the same experiment to see if they get the same results.same results.

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Visualizing with ModelsVisualizing with Models

If a scientist is studying something that is If a scientist is studying something that is too big or too small or will take too long to too big or too small or will take too long to see completely, they use a model.see completely, they use a model.

A A model model represents an idea, an event, or represents an idea, an event, or an object. It helps people understand how an object. It helps people understand how & why things happen.& why things happen.

Some models are accepted and some Some models are accepted and some such as the geocentric model shown here such as the geocentric model shown here are later disproved by evidence.are later disproved by evidence.

<http://abyss.uoregon.edu/~js/images/greek_cosmos.jpg>

What are high-tech models?What are high-tech models?

Computer models can be used to solve Computer models can be used to solve difficult mathematical equations. difficult mathematical equations.

A simulator can be used to create the A simulator can be used to create the same kind of conditions found in real life. same kind of conditions found in real life. For example, a flight simulator is a model For example, a flight simulator is a model of an airplane that can help a pilot test of an airplane that can help a pilot test different ways to solve a problem without different ways to solve a problem without endangering himself or the plane.endangering himself or the plane.

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Scientific Theories & LawsScientific Theories & Laws A scientific A scientific theorytheory is a way of explaining is a way of explaining

things or events based on what has been things or events based on what has been learned from many observations and learned from many observations and investigations that have been repeated investigations that have been repeated many times. New information in the future many times. New information in the future may change the theory.may change the theory.

A A scientific law scientific law is a statement about what is a statement about what happens in nature all the time. It explains happens in nature all the time. It explains what will happen under certain conditions what will happen under certain conditions but not why or how it happens. Gravity is but not why or how it happens. Gravity is a scientific law.a scientific law.

Limitations of ScienceLimitations of Science

Science cannot explain everything such as Science cannot explain everything such as questions about emotions or values. A questions about emotions or values. A survey of peoples’ opinions would not survey of peoples’ opinions would not prove that everyone believes the same.prove that everyone believes the same.

Scientists make predictions when they Scientists make predictions when they perform experiments which test and verify perform experiments which test and verify whether they are right by using a scientific whether they are right by using a scientific method.method.

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Using Science- TechnologyUsing Science- Technology

Technology Technology is the application of science.is the application of science. For example, science is used when a For example, science is used when a

chemist develops a new material. When chemist develops a new material. When this new material is used on the space this new material is used on the space shuttle, technology is applied.shuttle, technology is applied.

Not all technology is good. Some people Not all technology is good. Some people question the benefits of certain question the benefits of certain technology. Society must make decisions technology. Society must make decisions about these issues. Learning more about about these issues. Learning more about science can help you do that.science can help you do that.

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Put the steps for scientific method Put the steps for scientific method in order:in order:

Analyze the data

Test the hypothesis

State the problem

Draw conclusions

Gather information

Form a hypothesis

Put the steps for scientific method Put the steps for scientific method in order:in order:

Gather information

Form a hypothesis

Analyze the data

Draw conclusions

State the problem

Test the hypothesis

2 – Standards of Measurement2 – Standards of Measurement

What You’ll Learn:What You’ll Learn: SI Units and symbols for length, volume, SI Units and symbols for length, volume,

mass, density, time, and temperaturemass, density, time, and temperature How to convert related SI unitsHow to convert related SI units

2 - Standards of Measurement2 - Standards of Measurement

A A standardstandard is an is an exact quantity that exact quantity that people agree to use people agree to use to compare to compare measurements.measurements.

It is always the same It is always the same quantity no matter quantity no matter where it is used in the where it is used in the world.world.

<www.nasa.gov/centers><www.nasa.gov/centers>

Measurement SystemsMeasurement Systems A measurement is a way to describe the A measurement is a way to describe the

world using numbers answering questions world using numbers answering questions such as how much, how long or how far.such as how much, how long or how far.

For a measurement to make sense, For a measurement to make sense, it must it must include a number and a unit.include a number and a unit.

The U.S. commonly uses English units The U.S. commonly uses English units such as inches, feet yards, miles, gallons such as inches, feet yards, miles, gallons and pounds.and pounds.

Most nations use the metric system which Most nations use the metric system which is based on multiples of ten.is based on multiples of ten.

What is the International System of What is the International System of Units?Units?

This system is This system is abbreviated from the abbreviated from the French French Le Systeme Le Systeme Internationale d’ Internationale d’ Unites.Unites.

The SI standards The SI standards are accepted and are accepted and used by scientists all used by scientists all over the world. over the world.

The table shows the The table shows the names & symbols for names & symbols for the 7 base units.the 7 base units.

<www.hcc.mnscu.edu/chem>

What are SI prefixes?What are SI prefixes?Prefix Symbol Multiplication factor

peta P 1015

tera T 1012

giga G 1 000 000 000 109

mega M 1 000 000 106

kilo k 1000 103

hecto h 100 102

deka da 10 101

deci d 0.1 10-1

centi c 0.01 10-2

milli m 0.001 10-3

micro µ 0.000 001 10-6

nano n 0.000 000 001 10-9

The SI system is easy The SI system is easy to use because it is to use because it is based on multiples of based on multiples of ten.ten.

A prefix is added to A prefix is added to the name of a base the name of a base unit to indicate how unit to indicate how many multiples of ten many multiples of ten it includes.it includes.

1 kilogram = 1 kilogram = 1000grams1000grams

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How do you convert between SI How do you convert between SI units?units?

Sometimes quantities are measured using Sometimes quantities are measured using different units so they must be converted different units so they must be converted to similar units by using a conversion to similar units by using a conversion factor.factor.

new unit new unit = = 1000 mL1000 mL

Old unit 1LOld unit 1L

1.3 L X 1000mL/ 1L= 1,300mL1.3 L X 1000mL/ 1L= 1,300mL A length of rope measures 3,000 mm. A length of rope measures 3,000 mm.

How long is it in meters?How long is it in meters?

Measuring DistanceMeasuring Distance

Length Length measures the distance between two measures the distance between two points. The SI unit for length is the meter, about points. The SI unit for length is the meter, about the length of a baseball ball or longer than a the length of a baseball ball or longer than a yardstick.yardstick.

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How do you choose a unit of How do you choose a unit of length?length?

The unit you choose depends upon the The unit you choose depends upon the object being measured. By choosing the object being measured. By choosing the best unit you can avoid very large or very best unit you can avoid very large or very small numbers.small numbers.

Length of classroom would be measured Length of classroom would be measured in meters while the distance from school to in meters while the distance from school to your house would be measured in your house would be measured in kilometers.kilometers.

Measuring VolumeMeasuring Volume

Volume Volume is the amount of space an object fills. is the amount of space an object fills. The volume of a rectangular solid such as a The volume of a rectangular solid such as a brick is found by multiplying its length, width and brick is found by multiplying its length, width and height (V= l x w x h) thus units must be height (V= l x w x h) thus units must be expressed as cubic or to the third power. (mexpressed as cubic or to the third power. (m33))

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How do you measure the volume of How do you measure the volume of liquid?liquid?

Liquids do not have “sides” so measuring Liquids do not have “sides” so measuring their volume requires a container with their volume requires a container with known capacity.known capacity.

Common units for expressing liquid Common units for expressing liquid volume are liters, L and mL or milliliters. volume are liters, L and mL or milliliters.

1 mL= 1 cm1 mL= 1 cm33

1 L= 1000 cm1 L= 1000 cm33

How do we KNOWHow do we KNOW this? this?

<http://faculty.uca.edu/~march/bio1/scimethod/usepip5.jpg>

Measuring MatterMeasuring Matter

Mass is a measure of how much matter is in an Mass is a measure of how much matter is in an object. object.

A golf ball and a table tennis ball are about the A golf ball and a table tennis ball are about the same size, but the first has more matter, or same size, but the first has more matter, or mass, than the other.mass, than the other.

What is density?What is density?

Density Density of an object of an object is the amount of mass is the amount of mass in one cubic unit of in one cubic unit of volume of the object.volume of the object.

Find density by Find density by dividing an object’s dividing an object’s mass by its volume.mass by its volume.

D= m/VD= m/V

How do we KNOW what weHow do we KNOW what we

know?know?

<http://www.dmturner.org/Teacher>

Measuring TimeMeasuring Time

Sometimes scientists need to know how long it Sometimes scientists need to know how long it takes for something to happen.takes for something to happen.

The SI unit of time is second, s, measured with a The SI unit of time is second, s, measured with a clock or stopwatch.clock or stopwatch.

Jantar Mantar is the biggest of five astronomical observatory build by Maharaja Jai Singh during the period 1727-1734 in north India. The observatory consists of fourteen major geometric devices (or yantra in Hindi) for measuring time, predicting eclipses, etc.

The Samrat Jantar, the largest instrument, is 90 feet high, its shadow carefully plotted to tell the time of day.

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Measuring TemperatureMeasuring Temperature

Sometimes you need to measure how much Sometimes you need to measure how much something heats up or cools down.something heats up or cools down.

Temperature is a measure of how hot or cold Temperature is a measure of how hot or cold something is.something is.

What is Fahrenheit?What is Fahrenheit?

The Fahrenheit scale The Fahrenheit scale is based on the is based on the temperature of the temperature of the human body, 98.6human body, 98.6°F.°F.

On this scale, water On this scale, water freezes at 32°F and freezes at 32°F and boils at 212°F.boils at 212°F.

<http://media.nasaexplores.com/lessons/03-015/images/thermometers.jpg>

What is Celsius?What is Celsius?

Scientists use the Scientists use the Celsius scale to Celsius scale to measure temperature.measure temperature.

On this scale, water On this scale, water freezes at 0freezes at 0°C and °C and boils at 100°C.boils at 100°C.

The scale is divided The scale is divided into 100 equal into 100 equal degrees between degrees between freezing and boiling.freezing and boiling.

<http://media.nasaexplores.com/lessons/03-015/images/thermometers.jpg>

What is Kelvin?What is Kelvin?

The SI unit for The SI unit for measuring measuring temperature is Kelvin, temperature is Kelvin, K.K.

0 K is called absolute 0 K is called absolute zero, the coldest zero, the coldest possible temperature possible temperature = -273= -273°C.°C.

Divisions on K & C Divisions on K & C scales are equal so to scales are equal so to convert to K, add 273 convert to K, add 273 to C.to C.

<http://media.nasaexplores.com/lessons/03-015/images/thermometers.jpg>

SI Base Unit

Length Time

is is is is

Kilogram Kelvin

for forfor for

SI Base Unit

Length Time

is is is is

Meter Kilogram Kelvin

for forfor for

SI Base Unit

Length Mass Time

is is is is

Meter Kilogram Kelvin

for forfor for

SI Base Unit

Length Mass Time

is is is is

Meter Kilogram Second Kelvin

for forfor for

SI Base Unit

Length Mass Time Temperature

is is is is

Meter Kilogram Second Kelvin

for forfor for

3 – Communicating with Graphs3 – Communicating with Graphs

What You’ll Learn:What You’ll Learn: How graphs are usedHow graphs are used How to distinguish between dependent How to distinguish between dependent

and independent variablesand independent variables

A Visual DisplayA Visual Display

A A graph graph is a visual display of information is a visual display of information or data. or data.

Scientists often use graphs to display Scientists often use graphs to display results of their experiments.results of their experiments.

Patterns in the data show better in a graph Patterns in the data show better in a graph than if the data were listed in a table.than if the data were listed in a table.

The most common types are line, graph or The most common types are line, graph or bar graphs. Each type is used to display bar graphs. Each type is used to display different types of data.different types of data.

Line GraphsLine Graphs

Line graphs show Line graphs show change over time. change over time.

It can show more than It can show more than one event on the one event on the same graph. same graph.

Horizontal or x-axis Horizontal or x-axis always used for the always used for the independent variable.independent variable.

Vertical or y-axis used Vertical or y-axis used for the dependent for the dependent variable.variable.

<www.thechemguy.com>

Line GraphsLine Graphs

Select a scale that Select a scale that makes your graph makes your graph sensible & readable. sensible & readable. Spread out the Spread out the information.information.

Plot data points (x,y) Plot data points (x,y) then draw a line to then draw a line to connect the points.connect the points.

All data must use the All data must use the same units.same units.

<www.thechemguy.com>

Using Excel to graphUsing Excel to graph0 51 12.52 203 27.54 35

In the A column enter In the A column enter your x data; in the B your x data; in the B column enter your y column enter your y data.data.

Go to chart wizard on Go to chart wizard on the tool bar; choose the tool bar; choose XY (scatter), then XY (scatter), then next. It will set your next. It will set your range in step 2.range in step 2.

Excel GraphingExcel Graphing

Position vs. time

y = 7.5x + 5

R2 = 1

0

5

10

15

20

25

30

35

40

0 1 2 3 4 5

Time 9(s)

Po

sit

ion

(m

)

Series1

Linear (Series1)

In step 3, you enter In step 3, you enter the chart title and the the chart title and the name & unit on the X name & unit on the X & Y axis as shown.& Y axis as shown.

Finish step 4, then Finish step 4, then right click on a data right click on a data point to add a trend point to add a trend line. To save ink, line. To save ink, right click one the right click one the gray area & click gray area & click clear.clear.

Excel GraphingExcel Graphing

Under Format trend Under Format trend line, choose options & line, choose options & check the bottom two check the bottom two options to add the options to add the equation & correlation equation & correlation of the line.of the line.

Excel allows you to Excel allows you to quickly and easily quickly and easily create accurate create accurate graphs with your data.graphs with your data.

Position vs. time

y = 7.5x + 5

R2 = 1

0

5

10

15

20

25

30

35

40

0 1 2 3 4 5

Time 9(s)

Po

sit

ion

(m

)

Series1

Linear (Series1)

Position vs. time

y = 7.5x + 5

R2 = 1

0

5

10

15

20

25

30

35

40

0 1 2 3 4 5

Time 9(s)

Po

sit

ion

(m

)

Series1

Linear (Series1)

The equation may be rewritten to clarify the relationship between position and time. Position in meters equals 7.5 times time in seconds plus five. The slope of the line (m) equals rise over run (15/2) or 7.5 and the y-intercept is 5.

Bar GraphsBar Graphs

Bar graphs are useful for comparing data Bar graphs are useful for comparing data collected by counting. Each bar shows a collected by counting. Each bar shows a number counted at a particular time.number counted at a particular time.

Again, the independent variable is plotted Again, the independent variable is plotted on the x-axis, & the dependent variable is on the x-axis, & the dependent variable is on the y-axis.on the y-axis.

The data are not related so the bars do not The data are not related so the bars do not touch.touch.

Circle GraphsCircle Graphs

A circle or pie graph A circle or pie graph is used to show how a is used to show how a certain quantity is certain quantity is broken down into broken down into parts.parts.

The circle represents The circle represents the whole and the the whole and the segments are parts or segments are parts or percentages of the percentages of the whole.whole.

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Graphs

May beMay be May be

To show To show To show

Graphs

May beMay be May be

To show To show To show

Line

Graphs

May beMay be May be

To show To show To show

Line Bar

Graphs

May beMay be May be

To show To show To show

Line Bar Circle

Graphs

May beMay be May be

To show To show To show

Line Bar Circle

Trends or change over time

Graphs

May beMay be May be

To show To show To show

Line Bar Circle

Trends or change over time

Information collected by counting

Graphs

May beMay be May be

To show To show To show

Line Bar Circle

Trends or change over time

Information collected by counting

Proportional parts of a whole