Unit 21: Foundations of Scientific Inquiry and Experimentation

Day 10 of 30

Fair tests: changing one variable

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Learning Objective

Students will be able to explore fair tests and changing one variable.

Today's Lesson

In this lesson, we'll explore fair tests: changing one variable. Scientific inquiry allows us to investigate and explain natural phenomena.

A fair test is an experiment where you change only one variable and keep everything else the same. This way, you know that any differences in results are caused by the variable you changed, not something else. For example, to test which paper towel is strongest, use the same size towel, same amount of water, same weights—change only the brand. Fair tests give reliable results. Without controls, you can't be sure what caused the outcome!

As you work through today's material, pay attention to the examples and try to identify the patterns or strategies being used. This will help you apply these concepts to new problems.

Take notes on key points and make connections to what you've already learned in previous lessons.

Key Terms
Variable

A symbol representing an unknown or changing quantity

Investigate

To examine systematically through observation and experiment

Activities
Instructions
1. Read the background information on fair tests: changing one variable. 2. Form a hypothesis before beginning. 3. Conduct the investigation following procedures. 4. Record observations and analyze results.
Materials Needed
  • Lab notebook
  • Investigation materials
  • Safety equipment if needed
Practice Problems
1

Based on today's lesson, what is one thing you observed or learned?

Hint: Think about the main topic.
2

How could you test or investigate this topic further?

Hint: What experiment could you do?
3

Why is this topic important in the real world?

Hint: Think about everyday applications.

Teaching Tip

For this age group: Balance direct instruction with collaborative activities. Allow students to explain their thinking and make connections to prior knowledge when exploring fair tests: changing one variable.

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