Practical questions

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:

  1. Required Practical Activity 9: Measure the population size of a common species in a habitat. Use sampling techniques to investigate the effect of a factor on the distribution of this species.
  2. Required Practical Activity 10: Investigate the effect of temperature on the rate of decay of fresh milk by measuring pH change.

These questions have been written by Bitesize consultants as suggestions to the types of questions that may appear in an exam paper.

Sample question 1 - Foundation

Question

Describe the method used to investigate the speed of reaction times. [4 marks]

Four from:

  1. Person A holds out their hand with a gap between their thumb and first finger.
  2. Person B holds the ruler with the zero at the top of person A's thumb.
  3. Person B drops the ruler without telling Person A and they must catch it.
  4. The number level with the top of person A's thumb is recorded in a suitable table. Repeat this ten times.
  5. Swap places, and record another ten attempts.
  6. You can use the conversion table to help convert your ruler measurements into reaction time or just record the catch distance in cm.

Sample question 2 - Foundation

Question

Describe how you could adjust this method to show the effect of stimulants in reaction times. [2 marks]

Two from:

  • Both person A and B both drink a caffeinated drink after they have measured their reaction times.
  • Wait a few minutes for the caffeine to have an effect on the nervous system.
  • Repeat the experiment and compare the results.

Sample question 3 - Higher

Question

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.

WomanReaction time before alcoholReaction time after alcohol
10.400.51
20.350.64
30.190.52
40.400.60
50.290.58

(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.