How to plan a fair test
Every fair test has three jobs for its variables. Get these three right and your test will be fair: you change one thing, measure the effect, and keep everything else the same.
Plan your own fair test
Plan a fair test for this question:
"Which type of ball bounces the highest?"
1. Fill in the three jobs of a variable for your investigation.
| Variable job | My plan |
|---|---|
| CHANGE (the one thing I make different) | |
| MEASURE (what I observe, and how) | |
| KEEP THE SAME (at least two things) |
2. Write your prediction. Remember: say what you think will happen and why.
3. Check yourself: have you changed only one thing? Tick when you are sure.
My test is fair:
Exit ticket
For this investigation — "Does warm water or cold water dissolve sugar faster?" — write:
One variable to change:
One variable to keep the same: