View source for GCSE Biology Required Practical: Factors affecting Human Reaction Time

==Key Stage 4==
{{#ev:youtube|https://www.youtube.com/watch?v=Ws5qVXYHRnQ}}
===Meaning===
Investigate a factor affecting [[human]] reaction time.
===Method===
Investigate whether practice can improve [[human]] reaction time.
*[[Independent Variable]] - Amount of practice.
*[[Dependent Variable]] - Reaction time.
*[[Control Variable]]s - The same person being tested. The same person administering the test.

#The subject places the forearm on a table with the hand hanging over the edge.
#A second person holds a metre ruler from the very top and allow it to hang from their fingers with the 0cm mark level with the top of the subject's hand.
#The subject holds their index finger and thumb apart allowing the ruler to fall between them.
#The second person gives no warning before dropping the ruler.
#The subject catches the ruler as quickly as possible between the thumb and index finger.
#Record the length of ruler that has passed through the subject's hand in metres.
#Convert the distance into reaction time with the following formula:
<math>t={{\sqrt{0.2 \times d}}}</math>

: Where t is the time and d is the distance the ruler has travelled.