Idea 4of 6Builds onMatch the instrumentThe one you change
Hold the rest still
How do you know what caused the change?
Today you'll discover
- why changing two things at once proves nothing
- the one thing you change and the rest you hold
- the word for what you hold still
Think firstA heavier ball, dropped from higher, lands later
You changed the mass AND the height, and the time changed. What caused it?
Decide first, then press Next. The plan box is where the controls are fixed.
The inquiry ring. After a prediction, the plan and collect-data boxes are named with one variable changed and the rest held. The last step asks what must stay the same when testing a pendulum's mass.
See the whole ideathe big idea and the key word, in one place
The big idea
Change one thing. Everything you hold still is a control.
Easy to get wrongA control is not the thing you are testing. Students often name the variable when asked for a control.
Key word
- control
- a quantity held the same across every trial so that it cannot be the cause of a change
Ready to use it?
- Name the variable and the controls of an experiment.