Ruler Drop Reaction Challenge

In pairs, one student drops a ruler without warning and the other catches it with two fingers; the inches it falls show their reaction time. Partners test different conditions to discover what speeds up or slows down a reaction.

How to play

1. Pairs at desks: A rests a forearm on the desk with the hand past the edge, thumb and index finger 1 inch apart at the zero mark (2 min).
2. Baseline test (3 min): B holds the top of the ruler and drops it without warning within 5 seconds; A catches it and reads the number by the thumb. Three tries each, record the best.
3. Non-dominant hand (2 min): repeat the test with the other hand.
4. Sound cue (3 min): A closes their eyes and B says 'Go!' at the moment of release.
5. Dual task (2 min): A counts backward by 3s while waiting for the drop.
6. Each pair adds their best scores to the class poster, and the class discusses which condition produced the fastest reactions (3 min).

Rules

• Drop without warning, but no fake-outs.
• Fingers do not close until the ruler starts to fall.
• Always hold the ruler by the top end and never throw it.
• Record your real scores honestly.

Variations

Adaptations

• Limited hand mobility: catch with the whole hand or trap the ruler against the desk.
• Visual impairment: always use the sound cue or a tap on the shoulder.
• Skill level: each student compares only with their own scores, with no class ranking.

Learning goals

• Measure and improve their own reaction time.
• Compare responses to visual and sound signals.
• Record data carefully and draw simple conclusions.

Equipment for a class of 25

• 12-inch rulers: 13
• cardstock: 2
• markers: 5

Teacher tip

Explain that fewer inches means a faster reaction: about 6 inches is a little over 0.15 seconds. Watch that nobody rests their fingers on the ruler before it drops.

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