Required practical 7: Reaction Time

• Method for measuring a person's reaction time:

  • Person 1 sits on a stool with good upright posture
  • Person 1 places the forearm of their dominant arm across the table with their hand hanging over the edge
  • Person 2 holds a ruler vertically with the zero centimeter mark between person 1's thumb and first finger
  • Person 2 drops the ruler at a random time for person 1 to catch with their thumb and first finger as quickly as possible
  • Person 2 records the measurement on the ruler level with the top of person 1's thumb
  • The test is repeated several times and a mean is calculated
• Conversion of results to reaction time:

  • Use a conversion table found online
• Independent variable:

  • Person having the reaction time tested
• Dependent variable:

  • Reaction time
• Control variables:

  • Stool working distance between thumb and first finger kept constant
  • Always measure the ruler at the top of the thumb
  • Keep room conditions the same (e.g., lighting, background noise)
• Other independent variables that could be investigated:

  • Effect of practice on reaction time
  • Effect of the hand catching the ruler (dominant vs. non-dominant hand)
  • Effect of certain chemicals (e.g., caffeine) on reaction time
• Safety precautions:

  • Ensure test subjects have no medical issues affected by caffeine
  • Conduct the test in a lab where hazardous chemicals are not normally used