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Knows that whenever an object is seen to speed up, slow down or change direction, we know that an unbalanced force (e.g., friction) acts on it.

The Rubber Band Problem

This challenge may be used to introduce the concepts of friction, force, and/or inertia, or it can be used to reinforce them.

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Earth Turns? Prove It!

We are all told that the Earth turns and we accept that. But an actual demonstration of how scientists proved this can have lasting impact on the acceptance of this authoritative statement and also on how students judge other authoritative statements for themselves, scientific or otherwise. Satisfying oneself that Earth does actually rotate shows what can be done to encourage such thinking.

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