Reaction Time

i have decided that i will use the ruler test to test the reaction time as i read through the online reaction time tester (the site i posted before http://getyourwebsitehere.com/jswb/rttest01.html) and it says its not accurate and its not a scientific tool:

i researched a bit on reaction time and according to this site http://www.sciencebuddies.org/mentoring/project_ideas/HumBeh_p009.shtml

"Reaction time is the time that elapses between a sensory stimulus and the response to that stimulus. Thus, it is a measure of the total time necessary for a chain of internal events:

• the stimulus activates one or more sensory receptors,
• the receptor(s) send a signal to the central nervous system (CNS),
• the CNS processes the incoming signal and elicits a neural response,
• which must then travel to the appropriate muscles in order to generate the physical response.

"Under optimal conditions of attention, we can respond to a sensory stimulus in 120 to 150 ms." (Ghez, 1991) The shorter time (120 ms) is for proprioceptive or auditory stimuli. (Proprioceptive stimuli result from mechanical displacement of the muscles or joints. An example is when your doctor taps your knee to test your reflexes. Your doctor is checking your reaction time.) The longer time (150 ms) is for visual stimuli, due to additional synapses in the retina. Reaction time will be even longer if we need to decide between several alternative choices of response (Ghez, 1991). "

i did some research on the different methods of the ruler drop experiment to test reaction time and came up with one my self:
1. the sitter should be seated with her arm resting on the table with just the hand over the table.
2. The top of the 1m ruler is held between the outstretched thumb and index finger.
3.. the bottom of the ruler is dangling in between the testers thumb and index finger.
4. the tester is to keep watch the top of the ruler
5. When the ruler is dropped the tester is to grab the ruler as fast as possible
6. Measure and record the reaults
7. Analyse resluts (i.e. conver to m/s using the formula d = vt + ½at² where; d = distance in metres, v = initial velocity = 0, a = acceleration due to gravity = 9.81m/s², t = time in seconds)
8. Repeat steps 1-7 three times and calculate the average for each.