B5 - reaction time

• • the practical tests the effect of caffeine on reaction time
• 1. arm resting on edge of table
  2. ruler should be held by another person vertically between thumb and forefinger, making sure it is level with zero end
  3. ruler let go without warning
  4. person being tested should try catch ruler as quick as possible
  5. measure on number where ruler is caught, higher the number, slower the reaction time
  6. repeat 5 times and calculate mean distance
  7. person should drink caffeinated drink at repeat steps 1-6
• • control variables are:
  • use same person to catch ruler each time
  • always use same hand to catch ruler
  • ruler should be dropped from same height
• • computers can be used to test reaction time
  • a person could click the screen as soon as they see a stimulus
  • this can give a more precise reaction time because it removes the possibility of human error
  • it gives a more accurate measurement
  • it removes the possibility that the person can predict when to respond through reading body language