Identifying Independent, Dependent and Controlled Variables
About this lesson
Students read short experiment descriptions and work in pairs to name what is changed, what is measured and what is kept the same. They practise the core skill of planning a fair test. You need four experiment descriptions written on the board and scrap paper. It takes about 15 minutes.
- Grade
- 6
- Subject
- Science
- Time
- 15 min
- Prep
- 5 min
Objective
Students will identify the independent, dependent and controlled variables in a simple experiment and explain why controlled variables make a test fair.
Prep
5 min: write four short experiment descriptions on the board
Materials
- whiteboard and markers
- scrap paper
- pencils
Steps
- Model one example aloud: 'We drop a ball from 50 cm, 100 cm and 150 cm and measure its bounce height, so drop height is what we change (independent), bounce height is what we measure (dependent), and the same ball and floor are kept the same (controlled).'
- Point to the four experiments on the board, for example: water amount for a plant (50, 100, 150 mL) and plant height in cm; water temperature and the time a sugar cube takes to dissolve; paper airplane wing size and flight distance in metres; ramp height and how far a toy car rolls.
- Have pairs take one minute per experiment to write I, D and C on scrap paper, listing at least two controlled variables for each.
- After each experiment, call on a pair to share, and ask the class, 'What would go wrong if we did not keep that the same?'
- In the last two minutes, have each pair write their own one-line experiment question, then swap with a neighbouring pair to identify its variables.
Quick Check
Give one new example orally, such as testing how the number of paper clips on a paper helicopter affects its fall time, and have students show 1, 2 or 3 fingers to identify the independent variable from three spoken options.
Differentiation
Make it easier: Label the three variable types with simple questions on the board: What do I change? What do I measure? What stays the same?
Make it harder: Have students rewrite one experiment as a testable 'If… then…' hypothesis and name one variable that would be hard to control.
Good For
- Review
- Supply teacher
- End of day
- Early finishers
