Variables and Fair Tests (Grade 8)
Free printable Grade 8 science inquiry worksheet on variables. Students read three investigations and name the independent, dependent and controlled variables, then write a hypothesis.
Variables and Fair Tests
Read the three investigations, then name the variables in each. The independent variable is the one thing changed on purpose, the dependent variable is what is measured, and controlled variables are kept the same.
Investigation A. Liam pours 150 mL of hot water into four cups made of different materials: glass, plastic, foam and metal. Each starts at 80 degrees Celsius and sits in the same room. He records the temperature of each after 15 minutes.
Investigation B. Zara adds the same mass of marble chips to the same volume and concentration of acid, and measures how long the reaction takes to stop. She uses chips of four different sizes, from large lumps to fine powder, keeping the temperature the same.
Investigation C. Ethan grows four identical bean plants in the same soil, water and temperature, but gives them 4, 8, 12 or 16 hours of light per day under the same lamp. After three weeks he measures the height of each plant.
- 1.Investigation A: what is the independent variable?
- 2.Investigation A: what is the dependent variable?
- 3.Investigation A: name one variable that must be controlled (kept the same).
- 4.Investigation B: what is the independent variable?
- 5.Investigation B: what is the dependent variable?
- 6.Investigation B: name one variable that must be controlled (kept the same).
- 7.Investigation C: what is the independent variable?
- 8.Investigation C: what is the dependent variable?
- 9.Investigation C: name one variable that must be controlled (kept the same).
- 10.Investigation A: write a hypothesis. Use the form "if ... then ... because ...".
- 11.What are controlled variables?
- 12.What is the dependent variable in an investigation?