Reaction time

• What are reaction times important for?

  Thinking distances
• How can you test your reaction time?

  By conducting simple experiments
• What is a typical range for reaction times?

  Between 0.2s and 0.2s
• Why can't you measure reaction times with a stopwatch?

  Because reaction times are too short
• What is one method to measure reaction times?

  Using a computer-based test
• What is the procedure for the ruler drop test?

  1. Sit with arm resting on a table.
  2. Have someone hold a ruler at zero.
  3. Ruler is dropped without warning.
  4. Catch the ruler as quickly as possible.
  5. Measure the distance it fell.
  6. Longer distance indicates longer reaction time.
• What does the measurement on the ruler indicate?

  How far the ruler dropped
• What does a longer distance indicate in the ruler drop test?

  A longer reaction time
• How can you calculate the time for the ruler to fall?

  Using acceleration due to gravity
• What is the approximate value of acceleration due to gravity?

  9.8 m/s²
• If the ruler falls 20 cm, what is the formula to find the final velocity?

  $v^2 =$$u^2 +$$2as$
• What does $v$ represent in the equation $v^2 =$$u^2 +$$2as$?


  The change in velocity of the ruler
• How do you calculate time from acceleration and change in velocity?

  $t =$$\Delta v/a$
• What is the reaction time calculated from a change in velocity of 2.0 m/s and acceleration of 9.8 m/s²?

  $0.2s$
• Why should you repeat the ruler drop test multiple times?

  To improve accuracy of results
• What can you do to ensure a fair test in the ruler drop experiment?

  Use the same ruler for each repeat
• How can distractions affect reaction time?

  They may increase reaction time
• What should you calculate to compare reaction times with and without distractions?

  The mean reaction time
• What is the relationship between the distance the ruler falls and reaction time?

  The further it falls, the longer the reaction time
• How far did Mark catch the ruler in the afternoon?

  16.2 cm
• What is the first step to calculate Mark's reaction time in the afternoon?

  Use the distance fallen of 16.2 cm
• Why might Mark's thinking distance be longer in the evening?

  Due to fatigue or reduced visibility