A question worth asking
Show on a big screen"The pond will dry up early, because the rains were weak."
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A prediction says what you expect to happen. Rain is measured as depth, in millimetres (mm).
- A friend makes a prediction about the pond.
- "Do the rains feel weak?" is only a feeling.
- "How many millimetres of rain fell?" is a number.
- Compare it with a year the pond dried early.
The idea
A prediction is an expectation with a reason behind it. The reason comes from evidence, which is what we observe or measure. It is not a guess.
To test a prediction, ask what you can measure. Ask what happened in earlier years too. How many millimetres of rain fell this year? How much fell in the years the pond dried early? A question with only a yes or a no tells you less. A number can be compared with other years.
If a prediction matches what we see, we trust it more. If it does not, we check again.
Old beliefs can be tested too. Some say a black cat crossing the road brings bad luck. Ask what you could count. Count the trips that go wrong after a cat crosses. Count the trips that go wrong without a cat crossing. Use the same number of trips each time. If both counts look alike, the belief gains no support.
Try the lab to finish this lesson.