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Logic

The mystery rule

Work out how a set of everyday objects has been sorted.

  • 6-9
  • 10-13

About 10 min

What you’ll need

  • Six to ten safe household objects

How to do it

  1. An adult secretly chooses a rule, such as ‘things made of metal’. Create two groups.
  2. The child tests ideas by moving one object and explaining why.
  3. Swap roles and let the child invent a fair rule.

The challenge

What feature might every object in this group share?

Feedback

Look for evidence that fits every item, then test the idea on a new object.

Can you think of an object that would disprove your rule?

Feedback

Trying to disprove an idea is a powerful reasoning habit.

What this practices

This activity practices classification, flexible thinking and explaining evidence.

For the adult

Treat guesses as experiments. There is no score, and needing clues is part of the activity.