You will complete ten required practical activities if you are studying GCSE Biology and twenty-one if you are studying GCSE Combined Science. You could be asked questions about the methods, safety precautions you might take, results and conclusions of these experiments.
In this Ecology section there are two required practical activities:
These questions have been written by Bitesize consultants as suggestions to the types of questions that may appear in an exam paper.
Describe the method used to investigate the speed of reaction times. [4 marks]
Describe how you could adjust this method to show the effect of stimulants in reaction times. [2 marks]
A scientist measured the reaction times of 5 women before and after drinking the same volume of alcohol. The women had to press a buzzer when a light flashed. This was repeated 5 times and the average reaction time was calculated for each woman.
|Woman||Reaction time before alcohol||Reaction time after alcohol|
(i) State one conclusion which can be drawn from the results. [1 mark]
(ii) Why was the experiment repeated five times for each woman? [1 mark]
(iii) Calculate the percentage change in the average reaction time for woman 4, after drinking alcohol. [1 mark]
(i) Alcohol slows reaction time
HINT - For this one it is important that the answer refers to slow reaction time. Stating that reaction time is decreased actually means that the reactions are faster - the opposite of the answer required.
(ii) Improves confidence in the results. Not accuracy or validity or a fair test.
(iii) (0.2 ÷ 0.4) × 100 = 50%
HINT - Divide the increase in the two numbers by the smaller number and multiply by 100.