Students test their reaction speed by trying to catch a falling ruler as quickly as possible. The activity demonstrates how the nervous system processes information from the eyes to the brain and then to the muscles to produce a response.

1. Prepare reaction timers by attaching a printed template to stiff card or taping it to a ruler.
2. Have students form pairs. One student holds the ruler vertically at the top, letting it hang down.
3. The second student positions their hand near the bottom of the ruler, ready to catch it but not touching.
4. The first student drops the ruler at a random time within 5 seconds.
5. The second student attempts to catch the ruler as quickly as possible.
6. Record the distance at which the ruler was caught and use the conversion chart to determine reaction time.
7. Repeat 3–5 times, varying the drop timing, then switch hands.
8. Swap roles so both students get tested.
9. Compare results for dominant and non-dominant hands.

Reaction Time: The Ruler Drop Test Experiment (muscle memory / science project) - Kids Fun Science:

Testing Reaction Time with Ruler Drop - John Biegun:

📄 Reaction Time Ruler - Science World: https://www.scienceworld.ca/resource/reaction-time-ruler/

📄 Reaction time test - NSW Government Eduction: https://education.nsw.gov.au/teaching-and-learning/curriculum/mathematics/mathematics-curriculum-resources-k-12/thinking-mathematically-resources/mathematics-s3-reaction-time-test

• Try with candy bars or long snacks instead of rulers, rewarding the fastest reaction.
• Test whether athletes or musicians have faster reaction times.
• Measure reaction times using peripheral vision instead of direct vision.
• Create a longer reaction timer to measure slower responses.

• Ensure rulers or objects used are lightweight and not sharp to avoid injury.
• Students should keep hands clear of faces to avoid accidental hitting when catching.
• Do not use glass or heavy objects as substitutes.

• What happens in the body that allows you to catch the ruler? (Messages travel from the eyes to the brain, then to the muscles via the spinal cord.)
• Why might the dominant hand be faster? (The dominant hand uses well-practiced neural pathways.)
• How can practice improve reaction time? (Repetition strengthens neural pathways, reducing decision-making time.)
• Why is there a delay between seeing the ruler drop and catching it? (Time is needed for nerve signals to travel and muscles to contract.)
• Do people who play sports or instruments have faster reaction times? (Likely yes, because of enhanced motor control and faster neural pathways.)