The Nature of ScienceThe Nature of Science

I. The Methods of ScienceI. The Methods of Science

A. What is science? 1. A method for studying the

natural world. 2. From Latin word scientia

which means “knowledge”

3. Follows rules or natural patterns

A. What is science? 1. A method for studying the

natural world. 2. From Latin word scientia

which means “knowledge”

3. Follows rules or natural patterns

4. Major Categories of Science

4. Major Categories of Science

a. Earth and Space Science b. Life Science c. Physical Science (matter and

energy)

d. The sciences often overlap

a. Earth and Space Science b. Life Science c. Physical Science (matter and

energy)

d. The sciences often overlap

5. Science Explains Nature5. Science Explains Nature

a. Explanations are modified as we learn more about the natural world often through new technology

a. Explanations are modified as we learn more about the natural world often through new technology

6. Investigations6. Investigations

a. Recording Observations b. Conducting experiments c. Building models/testing models

a. Recording Observations b. Conducting experiments c. Building models/testing models

B. Scientific Method- An organized set of investigation procedureswhich includes:

B. Scientific Method- An organized set of investigation procedureswhich includes:

• Stating a Problem• Researching & Gathering Information• Forming a hypothesis (a testable prediction)• Testing a hypothesis includes

• making observations• building or using a model• performing an experiment

• Gathering Data• Analyzing Data• Drawing Conclusions• Being Objective (eliminating bias)

• Stating a Problem• Researching & Gathering Information• Forming a hypothesis (a testable prediction)• Testing a hypothesis includes

• making observations• building or using a model• performing an experiment

• Gathering Data• Analyzing Data• Drawing Conclusions• Being Objective (eliminating bias)

1. Stating a Problem/Asking Question(s)1. Stating a Problem/Asking Question(s)

a. An event is observed in nature repeatedly

Example: Observation: the instruments in the nose of guided missiles didn’t always work.

a. An event is observed in nature repeatedly

Example: Observation: the instruments in the nose of guided missiles didn’t always work.

2. Researching and Gathering Information2. Researching and Gathering Informationa. learn as much as possible about

the background.b. Have others found info. that will

be helpful?

Example: Test recently created material on nose of guided missile.

a. learn as much as possible about the background.

b. Have others found info. that will be helpful?

Example: Test recently created material on nose of guided missile.

3. Forming a Hypothesis3. Forming a Hypothesis

a. A possible explanation for a problem using what you know and what you observe.

b. “A testable prediction.”

Example: NASA scientists knew a ceramic coating had been found to solve guided missile problem

a. A possible explanation for a problem using what you know and what you observe.

b. “A testable prediction.”

Example: NASA scientists knew a ceramic coating had been found to solve guided missile problem

4. Testing a Hypothesis4. Testing a Hypothesis

a. Conduct a controlled experiment to test the effect of one thing on another.

b. Usually contains at least 2 variables

a. Conduct a controlled experiment to test the effect of one thing on another.

b. Usually contains at least 2 variables

5. Variable - a quantity that can have more than one value.5. Variable - a quantity that can have more than one value.

a. Independent Variable b. Dependent Variable c. Constants d. Control

a. Independent Variable b. Dependent Variable c. Constants d. Control

Example of a Problem Statement:Example of a Problem Statement:1. Ask a Question: What variable has he greatest effect on

plant growth?

Or be more specific:2. State the effect of one thing on

another. The effect of fertilizer (or sunlight or watering schedule, or temperature, etc.) on plant growth.

1. Ask a Question: What variable has he greatest effect on

plant growth?

Or be more specific:2. State the effect of one thing on

another. The effect of fertilizer (or sunlight or watering schedule, or temperature, etc.) on plant growth.

Factors that affect plant growth:

(Possible variables)

Factors that affect plant growth:

(Possible variables)• type of fertilizer used• amount of sunlight• amount of water used• room temperature• type of soil

• type of fertilizer used• amount of sunlight• amount of water used• room temperature• type of soil

a. Independent Variable-a. Independent Variable-

the “you change it” variable.

- You might change the type of fertilizer to see how the plant’s growth is affected.

b. Dependent Variable - the “it changed” variable. b. Dependent Variable - the “it changed” variable. - The amount of growth results or

depends on what you did.

- The amount of growth results or

depends on what you did.

c. Constant - a factor that does not change when other variables change

c. Constant - a factor that does not change when other variables change

If you are testing the type of fertilizer, you may want to set up 4 trials, using the same soil, type of plant, same amount of sunlight and water

If you are testing the type of fertilizer, you may want to set up 4 trials, using the same soil, type of plant, same amount of sunlight and water

ConstantsConstants

Set up an experiment to test the effectiveness of 3 different fertilizers

*only change one variable at a time * Use 3 groups of plants – same type,

bought from same store, same amount of water, same amt. sunlight, etc.

Set up an experiment to test the effectiveness of 3 different fertilizers

*only change one variable at a time * Use 3 groups of plants – same type,

bought from same store, same amount of water, same amt. sunlight, etc.

d. Control-The standard by which test results can be

compared.

d. Control-The standard by which test results can be

compared.

1. Why use a control ? 1. Why use a control ?

That way you know that if all of the other plants grow 2-3 cm and the 4th plant only grows 1.5 cm, you can infer that it was due to the fertilizer.

• One group of plants is not fertilized, but the constants remain the same.

That way you know that if all of the other plants grow 2-3 cm and the 4th plant only grows 1.5 cm, you can infer that it was due to the fertilizer.

• One group of plants is not fertilized, but the constants remain the same.

6. Visualizing with Models6. Visualizing with Models

1. Models in history2. High-Tech Models – computer

simulations; algorithms; flight simulator

1. Models in history2. High-Tech Models – computer

simulations; algorithms; flight simulator

7. Scientific Theories and Laws

7. Scientific Theories and Laws

a. Theory – an explanation of things or events based on knowledge gained from many observations.

b. not a guess c. repeatable with the same result d. A theory can explain a law.

a. Theory – an explanation of things or events based on knowledge gained from many observations.

b. not a guess c. repeatable with the same result d. A theory can explain a law.

8. Scientific Law8. Scientific Law

a. A statement about what happens in nature and seems to be true every time.

b. Predicts what will happen in a given set of conditions, but does not explain why

a. A statement about what happens in nature and seems to be true every time.

b. Predicts what will happen in a given set of conditions, but does not explain why

9. Technology9. Technology

Application of science to help people.

Can be controversial (i.e., genetic engineering, stem cell research)

Application of science to help people.

Can be controversial (i.e., genetic engineering, stem cell research)

Making ObservationsMaking Observations

Make a total of 20 observations of an Alka Seltzer tablet, 100-mL of water, and then time how long it takes for the tablet to dissolve in 100 mL of water.

Make a total of 20 observations of an Alka Seltzer tablet, 100-mL of water, and then time how long it takes for the tablet to dissolve in 100 mL of water.

1. What materials are readily available for conducting experiments on Alka- Seltzer?

1. What materials are readily available for conducting experiments on Alka- Seltzer?

2. How does Alka-Seltzer act?2. How does Alka-Seltzer act?

3. How can I change the set of Alka – Seltzer materials to affect the action?

3. How can I change the set of Alka – Seltzer materials to affect the action?

How could I increase the rate of dissolving?Brainstorm all possibilities:

Pick One:

How could I increase the rate of dissolving?Brainstorm all possibilities:

Pick One:

Write a problem statement: Write a problem statement:

The effect of ______________ on independent variable

___________________.dependent variable

The effect of ______________ on independent variable

___________________.dependent variable

Write a hypothesisWrite a hypothesis

If _______________then the rate of choose 1 independent variable

dissolving of the Alka-Seltzer will

increase/decrease. (pick 1)

If _______________then the rate of choose 1 independent variable

dissolving of the Alka-Seltzer will

increase/decrease. (pick 1)

4. How can I measure or describe the response of _________ to the change?

4. How can I measure or describe the response of _________ to the change?

Design an Experiment with Alka- Seltzer

Design an Experiment with Alka- Seltzer

    I. Problem Statement: The effect of (independent variable) __ on __(dependent variable)__.II. Hypothesis:  If ____________________ , then the Alka Seltzer will dissolve more quickly.III. Materials:IV. Procedure:V. Data and Observations:VI. Results and Conclusions

    I. Problem Statement: The effect of (independent variable) __ on __(dependent variable)__.II. Hypothesis:  If ____________________ , then the Alka Seltzer will dissolve more quickly.III. Materials:IV. Procedure:V. Data and Observations:VI. Results and Conclusions

II. Standards of MeasurementII. Standards of Measurement

Discover how long a foot is:Discover how long a foot is:

1. Measure the distance across your classroom using your foot as a measuring device.

2. Record your measurement and name your measuring unit.

3. Repeat steps 1 and 2 for each group member.

1. Measure the distance across your classroom using your foot as a measuring device.

2. Record your measurement and name your measuring unit.

3. Repeat steps 1 and 2 for each group member.

II. Standards of MeasurementII. Standards of MeasurementA. Units and Standards 1. Standard - an exact quantity that

people agree upon using for measurement

2. Cannot compare measurements without a standard

3. A measurement consists of a number and a unit.

A. Units and Standards 1. Standard - an exact quantity that

people agree upon using for measurement

2. Cannot compare measurements without a standard

3. A measurement consists of a number and a unit.

B. Measurement SystemsB. Measurement Systems

1. English System – (feet, yards, inches, miles, pounds, etc.)

2. Metric system – based on multiples of 10; devised by a group of scientists in the late 1700s.

1. English System – (feet, yards, inches, miles, pounds, etc.)

2. Metric system – based on multiples of 10; devised by a group of scientists in the late 1700s.

3. International System of Units (SI)3. International System of Units (SI)

a. improved version of metric system in 1960s

b. universally used and accepted by scientists world-wide

c. Each type of measurement has a prefix & base unit (meter, Liter, gram)

a. improved version of metric system in 1960s

b. universally used and accepted by scientists world-wide

c. Each type of measurement has a prefix & base unit (meter, Liter, gram)

4. SI Prefixes4. SI Prefixes

Kilo – Hecto- Deka – Basic Unit deci- centi- milli-

(k) (H) (D) (m, L, g, s) (d) (c) (m)

103 102 101 100 10-1 10-2 10-3

5. SI Standards of Measurement5. SI Standards of MeasurementQuantity Measured Unit Symbol

Length meter m

Mass kilogram k

Time second s

Temperature kelvin K

Amount of substance mole mol

Electric Current ampere A

Intensity of Light candela cd

ActivityActivity

Measure the length and width of an index card using the least precise to the most precise measuring device.

Measure the length and width of an index card using the least precise to the most precise measuring device.

Ruler Length Width

1

2

3

4

Data

7.

6. Significant Figures6. Significant Figures

All of the numbers in a measurement known for certain plus an estimated digit.

(See Handout)

All of the numbers in a measurement known for certain plus an estimated digit.

(See Handout)

1. All digits 1-9 are significant. Example: 129 has 3 significant digits

2. Zeros between significant digits are always significant.

Example: 5007 has 4 significant digits

3. Trailing zeros in a number are significant only if the number contains a decimal point.

Examples: 100.0 has 4 significant digits 100. has 3 significant digit 100 has 1 significant digit

4. Zeros in the beginning of a number whose only function is to place the decimal point are not significant.

Example: 0.0025 has 2 significant digits 0.004 has 1 significant digit

5. Zeros following a decimal significant digit are significant.

Example: 0.000470 has 3 significant digits 0.47000 has 5 significant digits

ATLANTIC-PACIFIC RULE

ATLANTIC-PACIFIC RULE

If the decimal is ABSENT, start with the first non-zero number on the ATLANTIC side and count going LEFT.

If the decimal is PRESENT, start with the first non-zero number on the PACIFIC side and count going RIGHT.

Precision vs. AccuracyPrecision vs. Accuracy

Scientific NotationScientific Notation

How to write a very large number, such as

46,350,000 = 4.635 x 107

coefficient

Move the decimal until you get to a number 1- 9.9The number of times moved is equal to the

exponent.

How to write a very large number, such as

46,350,000 = 4.635 x 107

coefficient

Move the decimal until you get to a number 1- 9.9The number of times moved is equal to the

exponent.

When the number is less than one, the exponent will be negative.

0.000224 = 2.24 x 10-4

When the number is less than one, the exponent will be negative.

0.000224 = 2.24 x 10-4

Scientific Notation PracticeScientific Notation Practice

1. 425 cm = 2. 36000 cg = 3. 0.00098 m = 4. 0.0135 kg =5. 1000.345 g =

1. 425 cm = 2. 36000 cg = 3. 0.00098 m = 4. 0.0135 kg =5. 1000.345 g =

Scientific Notation AnswersScientific Notation Answers

1. 425 cm = 4.25 x 102 cm2. 36000 cg = 3.6 x 104 cg3. 0.00098 m = 9.8 x 10-4 m4. 0.0135 kg= 1.35 x 10-2 kg5. 1000.345 g = 1.000345 x 103 g

1. 425 cm = 4.25 x 102 cm2. 36000 cg = 3.6 x 104 cg3. 0.00098 m = 9.8 x 10-4 m4. 0.0135 kg= 1.35 x 10-2 kg5. 1000.345 g = 1.000345 x 103 g

Calculations with Scientific Notation

Calculations with Scientific Notation

When adding or subtracting numbers in scientific notation, the power of 10 must be the same.

Example: 3.6 x 103 + 5.2 x 102 = 3.6 x 103 + 0.52 x 103 = 4.1 x 103

OR 36 x 102 + 5.2 x 102 = 41.2 x 102 = 4.1 x 103

When adding or subtracting numbers in scientific notation, the power of 10 must be the same.

Example: 3.6 x 103 + 5.2 x 102 = 3.6 x 103 + 0.52 x 103 = 4.1 x 103

OR 36 x 102 + 5.2 x 102 = 41.2 x 102 = 4.1 x 103

When multiplying numbers in scientific notation, multiply the coefficients, then ADD exponents.

Examples:1. (3 x 102 )(2 x 105) = 6 x 107

2. (4 x 104 )(5 x 105) = 20. x 109

= 2 x 101 x 109 = 2 x 1010

When multiplying numbers in scientific notation, multiply the coefficients, then ADD exponents.

Examples:1. (3 x 102 )(2 x 105) = 6 x 107

2. (4 x 104 )(5 x 105) = 20. x 109

= 2 x 101 x 109 = 2 x 1010

When dividing numbers in scientific notation, divide the coefficients, then SUBTRACT exponents. Examples1) 4 x 103 = 2 x 103-2 = 2 x 101

2 x 102

2) 4 x 10-3 = 2 x 10 -3- -2 = -3 +2 = 2 x 10 -1

2 x 10-2

Dimensional AnalysisDimensional Analysis

How many seconds are in one year?

How many seconds are in one year?

8. Converting Between SI Units8. Converting Between SI UnitsDimensional Analysis is a method

of problem-solving that focuses on the units used to describe matter.

Dimensional Analysis is a method of problem-solving that focuses on the units used to describe matter.

9. Dimensional Analysis 9. Dimensional Analysis

A conversion factor -a ratio of equivalent values

Example, 1 dozen = 12 eggs could be written:

1 dozen or 12 eggs 12 eggs 1

dozen

A conversion factor -a ratio of equivalent values

Example, 1 dozen = 12 eggs could be written:

1 dozen or 12 eggs 12 eggs 1

dozen

Examples:Examples:

1) 30 eggs = ______ dozen

30 eggs x 1 dozen = 2.5 dozen 12 eggs

1) 30 eggs = ______ dozen

30 eggs x 1 dozen = 2.5 dozen 12 eggs

2) 1.5 dozen = ______ eggs

1.5 dozen x 12 eggs = 18 eggs 1 dozen

2) 1.5 dozen = ______ eggs

1.5 dozen x 12 eggs = 18 eggs 1 dozen

3) If you buy 13.3 gallons of gasoline at $2.899/gallon, how much do you pay?

13.3 gal x $2.899 = $ 38.56 1 gal

(if it had been $2.89/gallon, it would be $38.44)

3) If you buy 13.3 gallons of gasoline at $2.899/gallon, how much do you pay?

13.3 gal x $2.899 = $ 38.56 1 gal

(if it had been $2.89/gallon, it would be $38.44)

Kilo – Hecto- Deka – Basic Unit deci- centi- milli-Kilo – Hecto- Deka – Basic Unit deci- centi- milli-

4) 1.225 L = ________ mL

1 L = 1000 mL

1.225 L x 1000 mL = 1225 mL 1 L

4) 1.225 L = ________ mL

1 L = 1000 mL

1.225 L x 1000 mL = 1225 mL 1 L

5) 5400 mg = ______ g

1000 mg = 1 g

5400 mg x __1 g__ = 5.4 g 1000 mg

5) 5400 mg = ______ g

1000 mg = 1 g

5400 mg x __1 g__ = 5.4 g 1000 mg

Kilo – Hecto- Deka – Basic Unit deci- centi- milli-

C. Measuring DistanceC. Measuring Distance

1. Length is the distance between 2 points.

2. Choosing a Unit of Length a. unit chosen depends on the size of

the object.

1. Length is the distance between 2 points.

2. Choosing a Unit of Length a. unit chosen depends on the size of

the object.

D. Measuring VolumeD. Measuring Volume

1. Volume – the amount of space occupied by an object

2. Volume formulas: Rectangular Solids: V = lwh Cylinder: V = πr2h Sphere: V = 4 πr3

3

1. Volume – the amount of space occupied by an object

2. Volume formulas: Rectangular Solids: V = lwh Cylinder: V = πr2h Sphere: V = 4 πr3

3

3. Measuring Liquid Volume3. Measuring Liquid Volume

a. Usually expressed in Liters (L) or milliliters (mL)

b. 1 cc = 1 cm3 = 1 mL

a. Usually expressed in Liters (L) or milliliters (mL)

b. 1 cc = 1 cm3 = 1 mL

4. Converting from Liters to cm34. Converting from Liters to cm3

1.5 L x 1000 mL x 1 cm3 = 1500 cm3

1 L 1 mL

1.5 L x 1000 mL x 1 cm3 = 1500 cm3

1 L 1 mL

E. Measuring MatterE. Measuring Matter

1. Mass – a measurement of the quantity of matter in an object. The kilogram is the basic unit of mass in SI.

1. Mass – a measurement of the quantity of matter in an object. The kilogram is the basic unit of mass in SI.

2. Density - the mass per unit volume of a material. ( D = m/v)2. Density - the mass per unit volume of a material. ( D = m/v)

Material Density (g/cm3)

Material Density(g/cm3)

hydrogen 0.00009 aluminum 2.7

oxygen 0.0014 iron 7.9

water 1.0 gold 19.3

3. Derived Units3. Derived Units

a. A unit obtained by combining different SI units

b. Examples: 1) density: g/cm3

2) volume: m3

a. A unit obtained by combining different SI units

b. Examples: 1) density: g/cm3

2) volume: m3

F. Measuring Time & TemperatureF. Measuring Time & Temperature

1. Time - the interval between 2 events

- SI unit of time is the second (s)

1. Time - the interval between 2 events

- SI unit of time is the second (s)

2. Temperature- measure of the average kinetic energy of the particles of matter

2. Temperature- measure of the average kinetic energy of the particles of matter

- SI unit of temp. is Kelvin (K) - Absolute Zero: 0 K is - 273°C ( 273° lower

than freezing pt. of water) - Do not use degree symbol with K. - Laboratory thermometers use Celsius scale- Fahrenheit scale will not be used the

science lab

- SI unit of temp. is Kelvin (K) - Absolute Zero: 0 K is - 273°C ( 273° lower

than freezing pt. of water) - Do not use degree symbol with K. - Laboratory thermometers use Celsius scale- Fahrenheit scale will not be used the

science lab

Temperature ConversionsTemperature Conversions

K= °C + 273 (Notice Kelvin does not have °)

°C = 5 (°F-32) 9

°F = 9 °C + 32 5

K= °C + 273 (Notice Kelvin does not have °)

°C = 5 (°F-32) 9

°F = 9 °C + 32 5

3. Percent Error Calculation3. Percent Error Calculation

% Error = |Accepted Value – Experimental Value | x 100 | Accepted Value |

% Error = |Accepted Value – Experimental Value | x 100 | Accepted Value |

Accepted Values for pure substances can be found in the Handbook of Chemistry and Physics.

Experimental Values are determined from measurements taken during an experiment.

III. Communicating with GraphsIII. Communicating with Graphs A. Graph - A visual display of

information or data

A. Graph - A visual display of information or data

B. Line Graphs B. Line Graphs 1. Can show any relationship where the dependent

variable changes to a change in the independent variable.

2. Often show changes over time.

3. Independent Variable is plotted on x-axis

4. Dependent variable is plotted on y-axis 5. Refer to the “Components of an Excellent Graph”

1. Can show any relationship where the dependent variable changes to a change in the independent variable.

2. Often show changes over time.

3. Independent Variable is plotted on x-axis

4. Dependent variable is plotted on y-axis 5. Refer to the “Components of an Excellent Graph”

C. Bar GraphsC. Bar Graphs

1. Useful for comparing information collected by counting.

1. Useful for comparing information collected by counting.

D. Circle GraphsD. Circle Graphs

1. Used to show how some fixed quantity is broken down into parts.

1. Used to show how some fixed quantity is broken down into parts.

2. Making a Circle (Pie) Graph2. Making a Circle (Pie) Graph

a. Use a protractor to make a circle graph. 1) Determine the percentage of each

component. (Make sure all %s add up to 100) 2) Change percentage to a decimal. 3) Multiply decimal by 360° 4) Draw a circle. Draw a line across the

diameter. 5) Use the protractor to measure each angle.

a. Use a protractor to make a circle graph. 1) Determine the percentage of each

component. (Make sure all %s add up to 100) 2) Change percentage to a decimal. 3) Multiply decimal by 360° 4) Draw a circle. Draw a line across the

diameter. 5) Use the protractor to measure each angle.