Introduction Unit

Lab Safety, Variables and Graphing

Lab Safety

Safety rules are important in the science lab because the lab is a dangerous place where accidents can happen.

General Safety Precautions...

• Work quietly and carefully. Never work alone.

• Listen carefully to the instructions of your teacher.

• Wear protective clothing when requested.

• Never eat or drink in the lab.

• Tie back hair and clothing when requested. Don’t wear loose fitting clothing or jewelry.

• Never do lab experiments at home unless requested by your teacher.

Safety Equipment...

1. Fire Extinguisher

2. Chemical Shower

3. Broken Glass Container

4. Fire Blanket

5. Eye and Face Wash

6. First Aid Kit

7. Fume Hood

8. Protective Clothing

Gloves Goggles

Lab Coat/ Apron

Handling Materials in the Lab...

1. Don’t touch anything until told to do so.

2. Waft odors; don’t snarf.

3. Carefully pour liquids away from your body.

4. Wash hands after handling materials and after class.

5. Clean up and dispose of materials as directed by your teacher.

6. If any part of your body comes in contact with a harmful chemical, rinse the area immediately and inform your teacher.

Before you begin an activity...

1. Read the activity carefully.

2. Make sure your work area is cleared of any potential hazards.

3. Don’t begin until instructed to do so.

4. Listen carefully to the instructions of the teacher.

Handling a Heat Source...

1. Use an electric hot plate whenever possible.

2. To heat a test tube on a hot plate, use a water bath.

3. Use only heat-resistant glass. Be sure that it is NOT cracked.

4. Always keep the open end of the test tube pointed away from people.

5. Never allow a container to boil dry. Use boiling chips.

6. Pick up hot objects using gloves or tongs.

7. Turn off the heat source when finished. Put away correctly.

8. Apply cool water to burns immediately.

WHMIS...

• Workplace Hazardous Materials Information System

• Used to provide information about a chemical before it is used. How is the chemical dangerous?

• There are 8 symbols in WHMIS.

1. Biohazardous Material

2. Compressed Gas

3. Corrosive Material

4. Flammable Material

5. Oxidizing Material

6. Poisonous Material

7. Dangerously Reactive Material

8. Toxic and Infectious Material

MSDS...

• Material Safety Data Sheet

• Provides information about the chemical you are using. For example if it is toxic and first aid treatments.

• Most MSDS sheets contain 8 common pieces of information.

1. Name of the Chemical

2. Dangerous Ingredients

3. Physical Data

4. Fire and Explosion Hazard Data

5. Reactivity Data

6. Toxicological Properties

7. Preventive Measures

8. First Aid Measures

Laboratory Equipment: Some Samples…

Balance: used to determine the mass of an object.

Beaker: used to measure and pour liquids.

Bunsen Burner: Allows you to heat chemicals.

Erlenmeyer Flask: Allows you to swirl liquids to mix completely.

Funnel: Allows the transfer of a liquid from one container to another. It also allows you to filter a mechanical mixture.

Graduated Cylinder: a precise measuring device also used to pour liquids.

Retort/ Ring Stand: used along with a ring clamp to safely heat liquids when using a bunsen burner.

Test Tube: Used to conduct chemistry with small amounts of chemicals.

Test Tube Clamp: used to hold a test tube during heating.

Clamps: Used to hold onto the “neck” of glassware while heating.

Tongs: used to safely heat solid materials.

The Scientific Method...

An organized way to conduct a scientific experiment.

There are 6 steps involved.

1. Purpose

The reason(s) for doing the investigation or activity.

Eg. To determine how studying effects science grades.

2. Hypothesis

Your best guess or prediction about the answer to the problem you are trying to solve.

Eg. The more you study the better your science grades.

3. Materials

The items necessary to carry out the investigation.

Eg. Science book

watch (for timing)

test

4. Procedure

A detailed, step-by-step description of what you are going to do; the method.

Eg. 1. Do science test without studying. Take test. Record score.

2. Study 2 hours. Record score.

3. Repeat 3 times and average.

5. Results and Observations

What you learn from doing the experiment using your 5 senses. The results may be given as…statements graphs

charts diagrams

tables

6. Conclusion

Your interpretations of the results. Stating whether your hypothesis was right or wrong. Often times making inferences. (a possible explanation for your observations; it may be right or wrong.)

Variables and Controls...

Located in the Procedure of an experiment.

Manipulated Variable

The part of the experiment that you change. There can only be ONE in each experiment.

Eg. The length of time spent studying science.

Responding Variable

The result; what happens.

Eg. The result on your science test.

Controls

The conditions of the experiment that must be kept the same to ensure you are testing what you set out to test. They keep the experiment fair.

• Person being tested

• subject tested

• where they study

• difficulty of test

• where the test is written

• health of person

Graphing...

A visual display of data that is easy to read.

Terms to Know...

• Interpolation: determining values between the known points.

• Extrapolation: determining values beyond or outside the known points.

• Origin: the point where the x and y axis intercept.

• Range: the difference between the highest and lowest values.

All you need to know to make an effective graph...

MALCOM X

MV on the left of a chart; MV on the x-axis of a graph