PHYSICS: Reaction Time Lab


            Have you ever wondered what your reaction time is?  In the blank write down what you think your reaction time is: __________. 

            Using the equation d=1/2at2 see if your group can come up with a method for actually measuring a person’s reaction time.  Write this method as a list of procedures that are numbered 1 to whatever.  Put these procedures on a separate sheet of paper titled “Procedures for determining a person’s reaction time”. Of all of the procedures you have written there is one procedure that is the most important one.  Write this procedure in bold type and underline it as well.

            Once you have come up with a set of procedures, you should also know what single quantity that you will need to measure and what single tool you will need to measure it, and exactly how this tool will be used. Put this information on a separate sheet of paper titled “Quantity to be measured, the tool needed to measure a person’s reaction time” 

            If your procedures are correctly written you should know exactly what data to collect and exactly how to collect that data.  On a third sheet of paper make a data table for each member of your group.  Title this page “Data Tables”.

            Using the data you collected you will be able to calculate your reaction time.  Write out these calculations on a fourth page titled “Calculations of Reaction Time”.  The student whose data are being used must be indicated.  The 3-column method must be used for each student’s calculation. 

            Provide a summary on the ‘Summary’ page.  This summary must include the original prediction each student wrote down on the top of this page. So, a typical summary should start with a brief description of what your group did and how you did it.  Then, each summary must have a comment that compares the predicted reaction time and the actual calculated reaction time. Finally, each member of your group must write a paragraph telling what they learned as a result of doing this lab.

            The lab report for this reaction time lab must be typed.  The rubric should be used as a guide to your report writing.













Rubric for the reaction time lab


Points earned and comments

Each member of your group stays on task and performs the duties appropriate to their position in the group according to the card drawn.  (10)


Your group keeps to itself and does not interact nor distract another group.  In addition your group does not enable another group to be off-task. (10)


Each member of your group’s Preliminary Predictions are realistic and written out according to procedure.  (10)



A useable and correct set of procedures is written, including: the most important procedure, the equation that is used and the use of the 3-column method. (10)


The correct quantity to be measured and the correct tool is specified.  The group demonstrates that they know how to use the tool and how to measure the quantity.  (10)


Data tables are clearly and correctly drawn for each member of the group and the correct data in the correct SI units are entered.  (10)


Calculations are completely and correctly done in the 3-column method and each student’s reaction time is clearly indicated.  (10)


A clearly and properly written summary is provided with an appropriate comment from each member of the group clearly indicated.  (10)












Since we are doing a lab using the equation for calculating the time it takes for and object to fall, I thought it might be interesting to use that same equation to calculate your ‘hang’ time.  For 15 points extra credit do the following:


  1. On one sheet of paper have the student write down what he or she thinks their hang time will be.
  2. On a second sheet of paper write a set of procedures for how to determine the hang time of a member of your group.  (You may determine the hang time for more than one member but you will not get more points for doing so.  Determining the hang time of one student is sufficient for 15 points extra credit.)
  3. On page three make a data table with the data entered in the correct SI units.
  4. Page four will show the calculations, in proper 3-column method, using the data collected on the data table.
  5. The fifth page will be a summary of this whole process including what each member of the group learned as a result of doing this extra credit.


Alternate Extra Credit

  1. If you are traveling at 88km/hr how far would you go in a time equal to your lab reaction time?
  2. Convert the distance to miles (divide by 1.609) then convert to feet (multiply be 5,280). 
  3. If you were driving at 32m/s how far would you go during your reaction time?
  4. Convert the distance to miles (divide by 1609) then convert to feet (multiply by 5280).
  5. If a driver is under the influence of drugs such as alcohol is their reaction time likely to be greater or less than when sober?
  6. Look on the Internet for information on how a drug like alcohol can affect a person’s reaction time.  Using this information recalculate #s 1-4.  Naturally, I will expect you to provide me with the appropriate URL so that I can confirm your Internet sources!