1. Warm Up #3
Where have you seen variables before? Explain what a variable is.

2. Nature of Science (NOS): Scientific Explanations
Lesson 3: Case Study
Nature of Science (NOS): Scientific Explanations

3. Essential Questions How do independent and dependent variables differ?
How is scientific inquiry used in a real-life scientific investigation?

4. Key Terms
Variable – any factor in an experiment that can have more than one value
Controlled experiments are experiments in which a scientific investigation that tests how one variable affects another.
Control group – contains the same factors as the experimental group, but the independent variable isn’t changed
Experimental group – used to study how a change in the independent variable changes the dependent variable

5. Key Terms
Dependent variable – the factor measured or observed during an experiment
Independent variable – the factor that you want to test; changed by the investigator to observe how it affects a dependent variable
Constants – the factors in an experiment that remains the same

6. Compare and Contrast
Container 1 – 50 mL of warm water with tablespoon of dry yeast and pinch of sugar
Container 2 – 50 mL of warm water with tablespoon of dry yeast
Observe both containers for 15 mins.
What were the constants in the experiment?
What was the independent variable?
What was the dependent variable?

7. Practice with Variables Worksheet
Step 1 – Define each term in your own words
Step 2 – Write a hypothesis for each experiment
Step 3 – Determine the independent variable and dependent variable for each experiment
Step 4 – Give the control group and experimental group for each experiment