Practical questions
You will complete 21 required practical activities if you are studying GCSE Combined Science: Trilogy. You could be asked questions about the apparatus, methods, safety precautions, results, analysis and evaluation of these experiments.
There will be a number of different types of practical based questions. Some will be on the set required practicals, some will cover the working scientifically terms and some will be on other science practicals which you might have done in class. Use all the information given in the question particularly any diagrams to help you understand what the question is about.
This page contains AQA material which is reproduced by permission of AQA.
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Dr Alex Lathbridge answers questions about practicals.
Sample question 1 - Foundation
Question
A student carried out a practical to investigate the extension of a spring.
Write a method the student could have used. [4 marks]
- set up a clamp stand with a clamp and hang a spring on it
- use another clamp and boss to fix a half metre rule alongside the spring
- record the metre rule reading that is level with the bottom of the spring
- hang a weight from the bottom of the spring
- record the new reading on the rule and the extension on the spring
- remove the weight and check the length of the spring
- repeat by adding more weights and record the readings on the rule
[4]
Steps should be logically ordered so that they could be followed by someone else to obtain valid results.
Sample question 2 - Foundation and Higher
Question
A student investigates rolling a marble down a track.
The image below shows how he sets up the investigation:
The student lets go of the marble from different heights.
He records:
- the height from which he drops the marble (the drop height)
- the height the marble rolls up the other side (the roll height)
a) What is one variable the student should control in the investigation? [1 mark]
Tick one box.
| A | Length of ruler | |
| B | Length of track | |
| C | Mass of marble | |
| D | Roll height |
| A |
|---|
| Length of ruler |
| B |
|---|
| Length of track |
| C |
|---|
| Mass of marble |
| D |
|---|
| Roll height |
b) What is the independent variable in the investigation? [1 mark]
Tick one box.
| A | Drop height | |
| B | Length of track | |
| C | Mass of marble | |
| D | Roll height |
| A |
|---|
| Drop height |
| B |
|---|
| Length of track |
| C |
|---|
| Mass of marble |
| D |
|---|
| Roll height |
This table shows his results:
| Drop height (cm) | Roll height 1 (cm) | Roll height 2 (cm) | Roll height 3 (cm) | Mean roll height (cm) |
| 20 | 15 | 14 | 14 | 14 |
| 40 | 29 | 33 | 32 | |
| 60 | 47 | 19 | 46 | 46 |
| 80 | 65 | 61 | 63 | 63 |
| Drop height (cm) | 20 |
|---|---|
| Roll height 1 (cm) | 15 |
| Roll height 2 (cm) | 14 |
| Roll height 3 (cm) | 14 |
| Mean roll height (cm) | 14 |
| Drop height (cm) | 40 |
|---|---|
| Roll height 1 (cm) | 29 |
| Roll height 2 (cm) | 33 |
| Roll height 3 (cm) | 32 |
| Mean roll height (cm) |
| Drop height (cm) | 60 |
|---|---|
| Roll height 1 (cm) | 47 |
| Roll height 2 (cm) | 19 |
| Roll height 3 (cm) | 46 |
| Mean roll height (cm) | 46 |
| Drop height (cm) | 80 |
|---|---|
| Roll height 1 (cm) | 65 |
| Roll height 2 (cm) | 61 |
| Roll height 3 (cm) | 63 |
| Mean roll height (cm) | 63 |
c) Calculate the mean roll height of the marble when it is dropped from 40 cm. [1 mark]
d) The student calculated the mean roll height for a drop height of 60 cm.
He did not include the result for test two in his calculation.
Why did the student leave out the result for test two? [1 mark]
a)
| A | Length of ruler | |
| B | Length of track | |
| C | Mass of marble | ✔ |
| D | Roll height |
| A |
|---|
| Length of ruler |
| B |
|---|
| Length of track |
| C |
|---|
| Mass of marble |
| ✔ |
| D |
|---|
| Roll height |
A control variable is something that should be kept the same throughout the investigation to make sure it does not influence the results.
b)
| A | Drop height | ✔ |
| B | Length of track | |
| C | Mass of marble | |
| D | Roll height |
| A |
|---|
| Drop height |
| ✔ |
| B |
|---|
| Length of track |
| C |
|---|
| Mass of marble |
| D |
|---|
| Roll height |
The independent variable is the thing that is changed in order to see how it affects the result (the dependent variable).
c) 31 [1]
Mean is calculated by adding the result and diving the total by the number of results used.
mean roll height = (29 + 33 + 32) ÷ 3
= 94 ÷ 3
= 31 (rounded to the nearest whole number)
d) The result for test two was anomalous. [1]
An anomalous result is one that does not fit the pattern, usually due to random errors. It should be ignored if it will influence the overall results.
Sample question 3 - Higher
Question
A student changed the force applied to a spring by adding weights.
The figure below shows a graph of her results:
a) Identify the pattern shown in the figure above. Explain your answer. [2 marks]
b) Give one way the student could improve her investigation. [1 mark]
c) Describe the relationship between work done and elastic potential energy in stretching a spring. [2 marks]
a) Extension is directly proportional to the force applied [1] because it is a straight line through the origin [1].
A straight line may be described as a linear relationship. A straight line passing through the origin (0,0) is directly proportional.
b) Any one of:
- test a greater range of weights
- test more springs
[1]
Testing a greater range or different springs will help to prove whether this relationship is always true, or just in certain conditions.
c) Work done is equal to elastic potential energy [1] as long as the spring does not go past the limit of proportionality [1].
This question requires making a link to learning about work done and energy transfers.
