Step 1 of 18 · Working scientifically · SC4-WS-02
Fair tests
Change one thing, measure one thing, keep everything else the same.
Learn it
Identify variables, write a testable hypothesis and plan a safe, valid investigation
Idea 1 of 4
Three kinds of variable
The independent variable is the one thing you change on purpose. The dependent variable is what you measure to see the effect. Controlled variables are everything else you keep the same, so they can't spoil the result.
Know it by heart
Say each one in your head, then tap to check.
Try it
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Experiment 1 of 5
Does hot water dissolve sugar faster?
To investigate the effect of water temperature on the time taken for a sugar cube to dissolve.
- Temperature of the water
- Time taken for the cube to dissolve
- Volume of water (100 mL)
- Mass of the sugar cube
- Whether the mixture is stirred
- Size of the beaker
A full-marks answer
Zara wants to find out whether the temperature of water affects how fast sugar dissolves. Identify the independent, dependent and two controlled variables, and write a hypothesis.
4 marksBuilt one line at a time — say the next line before you reveal it
- Independent variable: the temperature of the water.(the thing she changes on purpose)
Words to know
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Step 1 · last bit
Ready? Prove it.
A round of ten. Score 8 or more and this step is done — then on to data and graphs.