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Lesson 3 of 9

Say what you expect — before you look

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5 min

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Sugar goes into water. You say: "It will dissolve in 20 seconds." Then you stir. Dissolve means the sugar mixes in and cannot be seen.

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A prediction: 20 seconds, before testing.
Step 1 of 4
  1. A prediction: 20 seconds, before testing.
  2. Stir the sugar into the water.
  3. The real test finishes at 18 seconds.
  4. Said first, so the test could check it.

Prediction — what you expect, said before the test.

Said before the test, a can be proved wrong. Said after, it proves nothing, because you already know the result.

A wrong is useful. It is evidence: a fact that shows you something new. Changing your mind because of it is good science.

Try the lab to finish this lesson.