Idea 2of 6Builds onA question that can lose
The one you change
What do you change, and what do you watch?
Today you'll discover
- why a fair test changes just one thing on purpose
- which number you set, and which you read off
- the names for the one you set and the one you read
Think firstDoes a longer pendulum swing more slowly?
You will try three string lengths and time each swing. Which one do you set?
Decide first, then press Next. The plan box holds what you set; the data box holds what you read.
The inquiry ring. After a prediction, the plan box is named for the thing chosen on purpose, then the collect-data box for the thing read off the instrument, then the analyse box where the two are named. The last step asks which quantity is read in a ramp experiment.
See the whole ideathe big idea and the key word, in one place
The big idea
You set one thing and read one thing: two variables.
Compare themThe string length is set; the swing time is read. Swap them and the experiment makes no sense: nobody can choose how long a swing takes.
Key words
- independent variable
- the one quantity you change on purpose between trials
- dependent variable
- the quantity you measure to see how it responds to the change
Ready to use it?
- Name the independent and dependent variables of a described experiment.