Lesson 2 | Measurement and Scientific Tools · PDF fileobjects observed through it is called a(n) ... the internationally accepted system for measurement 6. ... Key Concept What are

20 Scientific Explanations

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Student Labs and Activities Page

Content Vocabulary 21

Lesson Outline 22

Content Practice A 24

Content Practice B 25

Math Skills 26

School to Home 27

Key Concept Builders 28

Enrichment 32

Challenge 33

Skill Practice 34

Lesson 2 | Measurement and Scientific Tools

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Scientific Explanations 21

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Content Vocabulary

Measurement and Scientific ToolsDirections: On the line before each clue, write the letter of the term that matches it correctly. Then answer the questions that follow.

LESSON 2

1. a summary

2. (SI)

3. occurs when a measurement is on target

4. 0.370 has three of these.

5. an interpretation

6. identified by 5, but not five

7. how similar or close measurements are to each other

A. explanation

B. digital

C. significant digits

D. International System of Units

E. precision

F. accuracy

G. description

8. Which unit of the International System of Units is used to measure mass?

9. Can a set of measurements be precise but not accurate? Explain.

10. How is the scientific use of the term digital different from the common use?

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Lesson Outline LESSON 2

Measurement and Scientific ToolsA. Description and Explanation

1. A spoken or written summary of observations is called

a(n) .

a. An observation that uses the senses is called a(n) observation.

b. An observation that uses numbers is called a(n) observation.

2. An interpretation of observations is called a(n) .

B. The International System of Units

1. The internationally accepted system for is the International System of Units (SI).

2. The seven units are the meter, kilogram, second, ampere, kelvin, mole, and candela.

3. A description of how close a measurement is to an accepted value is

called .

4. A description of how similar or close measurements are to each other is

called .

C. Measurement and Accuracy

1. Tools used to measure quantities can limit the of a measurement.

2. A thermometer with measurements divided into tenths is more

than a thermometer with measurements divided into whole numbers.

D. Significant Digits

1. When you take any measurement, some digits you know for

and some digits you estimate.

2. are the number of digits in a measurement that are known with a certain degree of reliability.

3. When you use significant , others can know how

certain your are.



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Lesson Outline continued

E. Scientific Tools

1. A science is used to record descriptions, explanations,

plans, and steps used in a scientific .

2. A(n) can be used to measure the mass of an object.

3. The temperature of substances is measured using a(n) .

4. The is the SI unit for temperature, but in the science

classroom, temperature is measured in degrees .

5. Thermometers should not be used to anything.

6. Liquids are held, poured, heated, and measured in

laboratory .

7. A(n) is used to observe small objects that cannot be observed with an unaided eye.

8. are used to compile, retrieve, and analyze data for

reports; to create and other documents; to send

information to others; and to research .

a. Hardware is made of the components of computers, such as monitors and keyboards.

b. is the term used for programs that run on computers.

F . Tools Used by Life Scientists

1. A handheld lens that , or enlarges, the image of the

objects observed through it is called a(n) lens.

2. To prepare objects or substances for observation under a compound microscope, you would use a thin, rectangular piece of glass called

a(n) .

3. Scalpels and scissors are tools that are used to

examine , organs, or prepared organisms.

4. A small glass or plastic tube similar to an eyedropper that is used to draw up liquids

and transfer them to another place is called a(n) .



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Content Practice A

Measurement and Scientific Tools Directions: On the line before each definition, write the letter of the term that matches it correctly. Each term is used only once.

LESSON 2

1. a spoken or written summary of observations

2. uses words to describe an observation

3. uses numbers to describe an observation

4. an interpretation of events

5. the internationally accepted system for measurement

6. a description of how close a measurement is to an accepted value

7. a description of how similar or close measurements are to each other

8. the number of digits in a measurement that are known with a certain degree of reliability

A. accuracy

B. description

C. explanation

D. International System of Units

E. precision

F. qualitative observation

G. quantitative observation

H. significant digits



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Measurement and Scientific ToolsDirections: Complete the chart with the correct terms and symbols from the word bank in the space provided. Each term and symbol are used only once.

ampere (A) candela (cd) kelvin (K) kilogram (kg)

meter (m) mole (mol) second (s)

SI Base Units

Quantity Measured Unit

1. length

2. mass

3. time

4. electric current

5. temperature

6. substance amount

7. light intensity

Directions: On each line, write the number that defines each prefix.

8. mega-

9. kilo-

10. hecto-

11. deci-

12. centi-

13. milli-

Content Practice B LESSON 2



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Significant DigitsThe precision of a measurement is limited by the measuring tool. For example, a meterstick marked with millimeters has greater precision than a meterstick marked with centimeters only. Scientists use significant digits to keep track of the precision of measurements. To determine the number of significant digits in a measurement, apply the rules in the table below. In the examples, significant digits are shown in bold.

Rule Example Number of Significant Digits

1. All nonzero numbers are significant.

5.431 4

2. Zeros between nonzero digits are significant.

101 3

3. Final zeros used after the decimal point are significant.

0.35000 5

4. Zeros used only for spacing the decimal point are not significant.

0.000004

1,250

1

3

How many significant digits are in the number 0.06070?

Step 1 Determine which rules apply. All four rules apply for this measurement. Rule 1: The 6 and 7 are nonzero numbers. Rule 2: The zero between 6 and 7 is significant. Rule 3: The last zero is significant. Rule 4: The left-most two zeros are used for spacing the decimal point.

Step 2 Count the number of significant digits. There are four significant digits: 0.06070.

PracticeHow many significant digits are in each number? Tell which rules apply.

Math Skills LESSON 2

1. 17.453

2. 1.01

3. 0.0100

4. 12,003,000

5. 0.00031

6. 88.0

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Measurement and Scientific ToolsDirections: Use your textbook to respond to each statement.

1. Part of the process of scientific inquiry is making and discussing observations. Descriptions and explanations are used to tell about observations, but descriptions and explanations contain different information.

Contrast the information in a description and the information in an explanation.

2. The International System of Units is a set of base units and prefixes that can be used to express measurements.

Explain why the International System of Units is important in scientific communication.

3. SI units and prefixes make it possible to convert from one SI unit to another.

Set up and solve a proportion calculation to convert 1,892 grams to kilograms.

4. Measurements can be evaluated to determine their accuracy and their precision.

Define accuracy and precision in your own words.

5. Scientists use significant digits to show the precision of measurements.

Identify the number of significant digits in the number 3,092.01. Explain your response.

School to Home LESSON 2

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Measurement and Scientific ToolsKey Concept What is the difference between accuracy and precision?

Directions: Label this diagram by writing the correct terms from the word bank on each line.

accurate accurate and precise

not accurate or precise precise but not accurate

Directions: Answer each question or respond to each statement on the lines provided.

5. What is accuracy?

6. What is precision?

7. Use the diagram to describe how accurate arrow shots differ from precise arrow shots.

8. When you measure a quantity, what factor can impact the accuracy of the measurement?

Key Concept Builder LESSON 2

1. 2. 3. 4.

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Measurement and Scientific ToolsKey Concept Why do scientists use significant digits?

Directions: Complete the chart with the correct terms in the space provided.

Significant DigitsRules

1. All nonzero numbers are significant.

2. Zeros between nonzero digits are significant.

3. Final zeros used after the decimal point are significant.

4. Zeros used solely for spacing the decimal point are not significant. The zeros indicate only the position of the decimal point.

Number Significant Digits Applied Rules

1.234 1. 2.

1.2 3. 4.

0.023 5. 6.

0.200 7. 8.

1,002 9. 10.

3.07 11. 12.

0.001 13. 14.

0.012 15. 16.

50,600 17. 18.



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Measurement and Scientific ToolsKey Concept What are some tools used by life scientists?

Directions: On the line before each statement, write T if the statement is true or F if the statement is false. If the statement is false, change the underlined word(s) to make it true. Write your changes on the lines provided.

1. A science journal is used to measure observations.

2. A triple-beam balance is used to measure the mass of objects.

3. A thermometer measures the temperature of substances.

4. Graduated cylinders are used to measure the volume of solids.

5. Microscopes enable you to see objects that are too large to be seen with the

unaided eye.

6. Scientists use computers to compile, retrieve, and analyze data.

7. A magnifying lens is a hand-held lens that enlarges the image of an object.

8. A slide is a thick, circular piece of glass that is used to prepare objects or substances for observation under a compound microscope.

9. A cover slip is a small glass or plastic tube used to draw up liquids and transfer

them to another place.




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Measurement and Scientific ToolsKey Concept What are some tools used by life scientists?

Directions: Complete the concept map with the correct terms from the word bank in the space provided. Each term is used only once.

degrees Celsius grams kilograms liter

milliliter temperature volume

Properties Measured by Life Scientists

mass

kelvin



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Clinical Trials and Scientific Methods

Enrichment LESSON 2

A clinical trial is a kind of scientific experiment that usually tests the safety and effectiveness of a medication to treat human illness. Clinical trials help answer questions about vaccines, new drugs, or new ways of using existing drugs. Before clinical trials on people can begin, many tests done in laboratories and on animals must yield promising results.

Protocol and ProtectionIn most controlled experiments in

science, the plan for performing an experiment is called the procedure. In a clinical trial involving people, it is called a protocol. The protocol includes a description of the type of people who can participate, the schedule, medications, and length of the study.

People who take part in a clinical trial know that the treatment they get might not be effective and that they might suffer adverse effects. People who participate can ask questions and drop out at any time.

The government has strict guidelines to safeguard human test subjects. Before clinical trials can begin, a drug must be proven low in risk and high in safety and effectiveness. An Institutional Review Board oversees the process to ensure human rights and ethical conduct of the trial.

PhasesPhase I is a trial on 20 to 80 people to

evaluate safety, side effects, and a safe dosage range. If Phase I is successful, Phase II will test an expanded group up to 100 people. Phase III studies more than 200 people to further determine safety, effectiveness, and side effects, and also to compare the drug to existing therapies. Phase IV studies are done after the drug is marketed and collects information about how effects vary among populations.

PlaceboPeople in a clinical trial are given an

experimental drug or another substance that is inactive and has no treatment value. The inactive substance is called a placebo. This is done as a way to assess a drug’s effectiveness. If an expected result occurs as often in the group receiving a placebo as it does in the group receiving the experimental drug, then a logical conclusion would be that the drug has little value.

People tend to predict outcomes and to anticipate events based on previous knowledge. To avoid complication, trial staff do not inform subjects which one they are receiving. This is called a blind study.

Applying Critical-Thinking SkillsDirections: Answer each question or respond to each statement.

1. Differentiate In a clinical trial, is the group that is taking the placebo or the group that is taking the trial drug considered the control? Explain.

2. Infer Why would a Phase I clinical trial be performed on so few people, when it is usually the case that more accurate results come from a larger sample size?

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Challenge

Tools for Scientific StudiesScientists use many different tools and instruments to make observations and gather

data. Often, just one or two tools are needed and then some investigations require a whole array of sophisticated instruments.

In the table below are three different observation scenarios. Think about how you would form and test a hypothesis for each of them. The first row contains a statement of an observation. In the second row, write a possible hypothesis. Remember, a hypothesis must be testable. In the third row, briefly describe a procedure you might use to test the hypothesis. For each investigation, organize a list of materials and scientific equipment you would need. List those in the last row. One of the elements is given for you in each scenario.

Observation

1. Plants that are spaced apart in a pot grow larger than plants that are close together.

2. Bread kept in a warm, moist environment grows a green-black mold in spots on the surface of the loaf.

3. Cats are more popular pets than dogs/Dogs are more popular pets than cats.

Hypothesis

Plants that are spaced apart in a pot grow larger than plants that are close together because they have more space or less competition for space and other resources.

Procedure

Materials and Equipment

photo source (Internet or cutouts); computer with statistical graphing software; calculator to tally results and find mean, median, and mode (or pencil); calculator; graph paper

Mode of Communication

of Results

labeled drawing of hyphae, mycelium, and reproductive structures of mold; written report of findings

LESSON 2

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How can you build your own scientific instrument? All organisms take in and release gases. Your cells take in oxygen and release carbon dioxide just like the cells of other animals, plants, fungi, protists, and some bacteria. However, many plant cells, some protists, and some bacteria also can take in carbon dioxide and release oxygen. In this lab, you will follow a procedure and build your own scientific instrument that measures the change in the volume of a gas.

Materials 500-mL Erlenmeyer flask two-hole stopper

rubber tubing, 15 cm 500-mL beaker

Also needed: short piece of plastic tubing, water, 100-mL graduated cylinder, plastic wrap (10 cm × 30 cm), bendable straws, food coloring (optional)

Learn It Scientists often follow procedures developed by other scientists to collect data. A procedure is a step-by-step explanation of how to accomplish a task. The steps in a procedure tell you what materials to use, how to use them, and in what order to perform specific tasks. Some procedures are simple, while others are more complicated and require a lot of practice and skill.

Try It 1. Read and complete a lab safety form.

2. Into each, an Erlenmeyer flask and a beaker, pour 350 mL of water. Pour 100 mL of water into a graduated cylinder.

3. Seal the graduated cylinder with plastic wrap. Place your hand over the plastic wrap and turn the cylinder upside down. Carefully place the sealed end of the graduated cylinder into the beaker of water. Pull off the plastic wrap without losing any water from the graduated cylinder. Have a team member hold it so that it doesn’t tip over.

4. Place one end of a bendable straw in one hole of a 2-hole stopper. Insert the plastic tubing into the other hole. Place one end of the rubber tubing over the tubing.

5. Without lifting the cylinder above the water’s surface, insert the free end of the long piece of tubing inside the cylinder. Have a team member continue to hold the cylinder.

6. Put the stopper in the flask. Record the initial reading of the water in the graduated cylinder below.

7. Gently blow into the straw and watch the change in volume of the water. Continue blowing into the straw until the graduated cylinder contains 50 mL of gas (air).

Follow a Procedure Skill Practice LESSON 2: 30 minutes

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Skill Practice continued

Apply It 8. Draw a diagram of your setup, also known as a eudiometer. Label all the parts, and

describe their functions.

9. Key Concept Describe a scenario in which a life scientist would use this instrument to measure gases.

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Documents

Lesson 2 | Measurement and Scientific Tools · PDF fileobjects observed through it is called a(n) ... the internationally accepted system for measurement 6. ... Key Concept What are