Thinking Scientifically
When scientists do tests or experiments, they always only change one thing and record another. All other things are kept the same. This is a An experiment in which only one thing (variable) is changed and another is recorded. All other things are kept the same..
If more than one things changes in a test or experiment this is not a fair test. Then we cannot know for certain what caused the changes.
Watch: Fair tests
Comparing the melting times of ice cream.
Child: Ice cream!
What makes ice cream melt??
Narrator: This is a good opportunity for a test, Molly…
Don’t forget to make it fair. Everything needs to be the same, so we need the same type of ice cream, the same quantity and you both need to hold it for the same amount of time!
Now we just need one thing different so we can compare what difference it makes.
Good thinking, if it’s hotter, does ice cream melt faster?
Mint and cola investigation
Watch: The mint and cola expirement
See the experiment in action with help from The Science Museum team.
Watch: What you need to know about fair tests
Find out about variables in this science clip.
Activity 1: Quiz
Activity 2: Quiz
Activity 3: Making an investigation fair
An investigation always starts with a question.
Write a fair test to answer this question: Do all plants grow better in soil?
Think about:
- What do you need to keep the same?
- What will you measure or observe?
Activity 4: How high do balls bounce?
Ask a responsible adult to help you with this activity.
You will need a ruler and several different types of ball, such as a tennis ball, a football and a golf ball.
- Choose a place in your house, garden or park where you can drop the balls from the same height.
- Ask the adult to use the ruler to measure how high the balls bounce.
How will you make sure this is a fair test?
All the balls must be dropped from the same height.
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