Working scientifically: fair tests and variables

Designing a fair test by changing one variable, measuring another, and keeping the rest the same

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Try each question. If you're stuck, leave it and come back. The answer key is on the last page.

1
What is a variable in a scientific test? A) Something in the test that can change B) A piece of lab equipment C) A type of microscope D) A scientist's notebook
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2
True or false? In a fair test you should change only ONE variable at a time. A) True B) False
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3
What is a fair test? A) A test where only one thing is changed and everything else is kept the same B) A test that everyone passes C) A test only girls can do D) A test with no rules
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4
True or false? In a fair test, control variables are kept the same. A) True B) False
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5
What is the INDEPENDENT variable? A) The variable that you choose to change B) The variable that you measure C) A variable that you keep the same D) A variable that disappears
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6
What is the DEPENDENT variable? A) The variable that you measure to see the result B) The variable that you change C) Something kept the same throughout D) The colour of your lab coat
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7
What are CONTROL variables? A) Variables you keep the same so the test is fair B) Variables you change every time C) Variables you measure carefully D) Variables that disappear partway through
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8
Test: 'Does ice melt faster in a warm room than a cold room?' Put each variable in the correct role. Put these in order: Independent: Room temperature, Dependent: Time taken to melt, Control: Same size of ice cube, Control: Same container
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9
Put these steps for a fair test in order. Put these in order: Decide the question to investigate, Decide what to change (independent variable), Decide what to measure (dependent variable), Decide what to keep the same (control variables), Carry out the test and record results
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10
True or false? Repeating a fair test and taking an average makes the results more reliable. A) True B) False
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Answer key

Working scientifically: fair tests and variables · for parents and teachers

1
Something in the test that can change
A variable is anything in an experiment that could change, like temperature, time or amount of water.
2
True
True. A fair test changes only ONE variable at a time. That way you know any difference in the result came from that variable.
3
A test where only one thing is changed and everything else is kept the same
In a fair test, only one variable is changed at a time so we know the change in results is due to it.
4
True
True. Control variables stay the same so they do not affect the results.
5
The variable that you choose to change
The independent variable is the one you deliberately change in the experiment.
6
The variable that you measure to see the result
The dependent variable is what you MEASURE. It depends on the independent variable you chose to change.
7
Variables you keep the same so the test is fair
Control variables are things you keep the same. If you don't control them, you can't tell what really caused the change in the result.
8
Independent: Room temperature, Dependent: Time taken to melt, Control: Same size of ice cube, Control: Same container
Independent = room temperature (changed). Dependent = melting time (measured). Controls = ice size and container (kept the same).
9
Decide the question to investigate, Decide what to change (independent variable), Decide what to measure (dependent variable), Decide what to keep the same (control variables), Carry out the test and record results
A good fair test is planned: choose the question, decide on each variable, then run the test and record what you find.
10
True
True. Repeating a test (and taking an average) makes results more reliable and helps you spot any odd results caused by mistakes.