B5 Investigating Reaction Time - practical (page 61) Flashcards
What is Reaction time?
it is the time it takes to respond to a stimulus - it’s often less than a second.
How can Reaction time be affected?
by factors such as age, gender or drugs.
Caffeine is a drug that can speed up a person’s reaction time.
How can the affect of caffeine on reaction time be measured?
1) Ther person tested should sit with their arm resting on the edge of a table (this should stop them moving their arm up or down during the test)
2) Hold a ruler vertically between their thumb and forefinger. Make sure that the zero end of the fuler is level with their thumb and finger. Then let go without giving any warning.
3) The person being tested should try to catch the ruler as quickly as they can - as soon as they see it fall.
4) Reaction time is measured by the number on the ruler where it’s caught. The number should be read from the top of the thumb. The further down the ruler it’s caught (i.e. the higher the number. the slower their reaction time.
5) Repeat the test several times then calculate the mean distance that the fuler fell.
6) The person being tested should then have a caffeniated drink (e.g. 300 ml of cola). After 10 minutes repeat steps 1 to 5.
7) You need to control any variables to make sure that this is a fair test. For example, you should use the sae person to catch the ruler each time, and that person should always use the same hand to catch the ruler. Also the ruler should always be dropped from the same height, and you should make sure that the person being tested has not had any caffeine (or anything else that may affect their reaction time) befre the start of the experiment is completed.
8) Too much caffeine can cause unpleasant side -effects, so the person being tested should avoid drinking any more caffeine for the rest of the day after the experiment is completed.
What other simple tests can be used to meaure reaction time, apart from a ruler?
a computer test can also be used to measure reaction time.
Give an example of a comper test to measure reaction time?
the person being tested has to click the mouse (or press a key) as soon as they see a stimulus on the screen, e.g. a box change colour.
Why can computers give a more precise reaction time?
because they remove the possibility of human error from the measurement.
How can the computer record the reaction time?
it can record the reaction time in milliseconds. It can also give a more accurate measurement.
What else is an advantage using a computer to measure reaction time instead of a ruler?
using a computer can remove the possibility that the person can predict when to respond - using the ruler test, the catcher may learn to anticipate the drop by reading the tester’s body language.
Some studens investigated the effect of an energy drink on reaction time. They measured their reaction times using a computer test. They had to click the mouse when the screen changed from red to green. Each student repeated the test five times before having an energy drink, and five times afterwards.
a) he results for one of the students before having the energy drink were as follows:
242 ms, 256 ms, 253 ms, 249 ms, 235 ms. Calculate the mean reaction time (2 marks)
b) Suggest two variables that the students needed to control during their investigation (2 marks)
a) 242 + 256 + 253 + 249 + 235 = 1235 (1 mark)
1235 ÷ 5 = 247 ms (1 mark).
b) Any two from e.g.
the hand each person used to click the mouse/the computer equipment/programme used/the amount of energy drink they consumed/they type of energy drink used/the time between consuming the energy drink and taking the test (2 marks)
