Scientific Variables Identification

Name:

Date:

🔬 Part 1: Understanding Variables

Key Terms:

Independent Variable (IV): The factor that is changed or manipulated

Dependent Variable (DV): The factor that is measured or observed

Controlled Variables (CV): Factors kept the same to ensure a fair test

1. Which of the following best describes an independent variable?

The variable that is measured in the experiment

The variable that is deliberately changed by the scientist

The variables that are kept constant

The variable that cannot be controlled

2. Why are controlled variables important in scientific investigations?

They make the experiment more expensive

They ensure the test is fair and reliable

They make the results more complicated

They are not important

🧪 Part 2: Identifying Variables in Investigations

3. Plant Growth Investigation: A scientist wants to test how different amounts of sunlight affect the height of sunflower plants over 3 weeks. Plants receive 2, 4, 6, or 8 hours of sunlight daily. All plants use the same soil, pot size, and watering schedule.

Independent Variable (IV): _________________________________

Dependent Variable (DV): ___________________________________

Controlled Variables (CV): __________________________________

4. Paper Plane Investigation: Students test how different paper plane designs affect flight distance. They use the same type of paper and the same person throws each plane with equal force.

Independent Variable (IV): _________________________________

Dependent Variable (DV): ___________________________________

Controlled Variables (CV): __________________________________

5. Dissolving Investigation: A student investigates how water temperature affects the time it takes for sugar to completely dissolve. They test water at 20°C, 40°C, 60°C, and 80°C, using the same amount of sugar and water volume each time.

Independent Variable (IV): _________________________________

Dependent Variable (DV): ___________________________________

Controlled Variables (CV): __________________________________

✏️ Part 3: Explaining Your Thinking

6. Choose ONE investigation from Part 2. Explain why it's important to control the variables you identified. What could happen if these variables weren't controlled?

7. Design your own simple investigation: How does _____________ affect _____________?

My investigation question: How does _________________________ affect _________________________?

Independent Variable (IV): _________________________________

Dependent Variable (DV): ___________________________________

Two Controlled Variables (CV): ______________________________

_________________________________________________________

8. Explain why your investigation would be a fair test: