🧪 Lab Basics
What should you wear to protect your eyes during a laboratory investigation?
Safety goggles.
What is the SI base unit for length?
Meter (m).
How many centimeters are in one meter?
100 centimeters.
What is the main purpose of science?
To investigate and explain the natural world using evidence.
What are the three parts of a CER?
Claim, Evidence, Reasoning.
You need to smell an unknown substance. What is the safe way to do this?
Use the wafting technique by gently moving vapors toward your nose. Never put your nose directly over the container.
What is the difference between accuracy and precision?
Accuracy is how close a measurement is to the accepted value. Precision is how close repeated measurements are to one another.
Convert 45 cm to meters.
0.45 m.
Why do scientists repeat investigations or conduct multiple trials?
To determine whether their results are consistent and reliable.
A student says, "I think this chemical is dangerous because it smells bad." Is this a strong scientific claim? Why or why not?
No. A bad smell alone is not sufficient evidence to determine whether a substance is dangerous.
What does PASS stand for when using a fire extinguisher?
Pull the pin, Aim at the base of the fire, Squeeze the handle, Sweep from side to side.
A student measures an object three times:
12.1 cm
12.2 cm
12.1 cm
The accepted value is 15.0 cm.
Are the measurements accurate, precise, both, or neither?
Precise but not accurate.
Convert 1.6 kg to grams.
1,600 g.
A scientist's hypothesis is not supported by the evidence. What should the scientist do?
Analyze the evidence and revise or reconsider the hypothesis.
A student claims that a reaction produced a gas. Their evidence is that a balloon attached to the container increased from 12 cm to 24 cm in circumference. Why is this useful evidence?
The increase in balloon size is an observable measurement that supports the claim that gas was produced.
Your lab partner spills an unknown liquid on the table. They immediately grab a paper towel and begin wiping it up. What should they have done instead?
Stop and notify the teacher, then follow the appropriate spill procedure.
14.9 cm, 15.0 cm, 15.1 cm
Student B records:
12.2 cm, 15.0 cm, 17.8 cm
The accepted value is 15.0 cm.
Which student is more precise?
Student A.
Convert 5.9 km to meters.
5,900 m.
Two scientists examine the same evidence but reach different conclusions. Does this automatically mean one of them is not doing science correctly? Explain.
No. Scientists can interpret evidence differently. They should examine the data, methods, assumptions, and additional evidence to determine why their conclusions differ.
A student concludes that listening to music causes higher test scores because students who listened to music scored higher.
What additional information should scientists investigate before accepting this conclusion?
They should investigate other variables and how the experiment was designed—for example, prior achievement, study time, sample size, type of music, and whether there was a control group.
During a lab, you notice your partner is not wearing goggles. They tell you, "Don't worry. We've done this experiment before and nothing happened." What is the best scientific response?
The student should put on the appropriate safety equipment because previous safe outcomes do not eliminate the risk of an accident.
A student records four measurements:
12.4 g, 12.6 g, 12.5 g, 12.5 g
What is the average measurement?
12.5 g.
A thermometer reads 25°C. What is the temperature in Fahrenheit?
77°F.
A student says, "A scientific theory is just a guess that scientists haven't proven yet." Is the student correct? Explain.
No. A scientific theory is a well-supported explanation of natural phenomena that has been tested repeatedly and is supported by substantial evidence.
Scientists conduct an experiment five times.
A student says, "Just delete Trial 5 because it doesn't match the others."
Should the scientist delete the result? What should happen instead?
No. The scientist should investigate why Trial 5 was different. There may have been an error, an unusual condition, or a legitimate reason for the result.