Survival of an organism depends on its ability to respond to changes in the environment. The nervous system allows fast acting but short lived responses.
You can carry out a number of investigations to determine the effect of a specific factor on human reaction times.
A suitable investigation could be the effect of caffeine or the amount of background noise in the room. A simple method to measure the effect is to use the ruler drop test.
Catch distance (cm) | Reaction time (ms) |
---|---|
1 | 50 |
5 | 90 |
10 | 140 |
15 | 170 |
20 | 200 |
25 | 230 |
30 | 250 |
Important: 1 millisecond (ms) is one thousandth of a second. (1/1000 s)
Attempt | Distance on ruler (cm) | |
---|---|---|
With noise | Without noise | |
1 | 25 | 18 |
2 | 38 | 15 |
3 | 36 | 22 |
4 | 31 | 24 |
5 | 38 | 13 |
What affect does noise have on the speed of reaction, measured in centimetres? Use data to support your answer. [3 marks]
When the person tried to catch the ruler without noise, they could catch it sooner than if there was noise in the background. [1 mark]
For example, the first set of data, with noise the distance was 25 cm, compared to without noise where it was 18 cm. [1 mark]
This suggests that noise increases the reaction time of the person in this experiment. [1 mark]
Tip - Make sure you include data to support your answer, as you are asked to do in the question.