ISA Guide
For Additional and triple Science
By Mr J Kenny
Section 1
There are usually 5 questions. Questions 1, 2, 3 and 5 are generally very similar and examples are given below.
Question 1 Write down your hypothesis.
Explain why you made this hypothesis.
Hypothesis
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Explanation
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(3 marks)
People who drop marks here tend to give an unclear explanation e.g. I made this hypothesis because it makes sense.
Question 2 Think about the research that you did to find out how to test your hypothesis.
Identify two sources that you used for your research.
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Which of these sources did you find the more useful?
Why was this source better than the other source?
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(3 marks)
People tend to drop marks here by saying why the better source was good without commenting on the second source.
Question 3 In this question you will be assessed on using good English, organising information clearly and using
scientific words where appropriate.
Describe how you plan to do your investigation to test the hypothesis given.
You should include:
 the equipment that you plan to use
 how you will use the equipment
 the measurements that you are going to make
 how you will make it a fair test
 a risk assessment.
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(9 marks)
People tend to drop marks here by
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not explaining how the equipment will be used, i.e. not giving step by step instructions on how to do the practical.
not stating control variables and how they will be controlled.
not organising their answer logically
poor spelling, punctuation or grammar.
or, Forgetting to do the risk assessment
Question 5 – completed before the exam
5 Make sure that you hand in your Candidate Research Notes and your blank table for the results with this paper.
You will be awarded up to two marks for your table.
(2 marks)
Marks dropped on this question are generally due to a lack of units on column headings.
Question 4 varies from paper to paper and examples include.
Question 4 In your investigation, you will need to control some of the variables.
Name one variable that you will need to control.
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Describe briefly how you will control this variable.
You should also explain why it is important to control this variable.
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(3 marks)
Question 4 It is better to repeat each measurement at least three times.
Explain why this is likely to give a more accurate result.
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(3 marks)
Very similar to a question in Section 2 which has a slightly different mark scheme. Make sure you cover all of the points in
BOTH mark schemes.
Question 4 To measure the length of the rubber band, you may use a half-metre rule.
What would be a suitable resolution for the scale on this half-metre rule?
Explain your answer.
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(3 marks)
Section 2
As with section 1 there are some questions which come up in most papers and some questions which vary with each
paper.
Questions that usually appear (but might not always have the same question number)
1 (a) (i) Do your results support the hypothesis that you investigated?
You should use any pattern that you can see in your results to support your answer.
You should include examples from your results.
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(3 marks)
Marks dropped are usually because examples are not quoted from results (e.g. write numbers from results table in your
answer).
1 (a) (ii) Did you get any anomalous results?
Explain your answer.
Your explanation should include examples from your results.
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(3 marks)
Marks dropped are usually for not including examples from results (e.g. writing numbers from the results table in your
answer).
If there are no anomalous results, you could quote the result that is furthest from your line/curve of best fit and say that it
is not far enough from the line/curve of best fit to consider it an anomaly.
1 (c) What was the independent variable in the investigation that you did?
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What was the range of the independent variable?
The range was from .................................................. to .................................................. .
Explain why this was or was not a suitable range.
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(3 marks)
Marks dropped are usually for:
 Getting confused between the independent and dependent variable.
 Not including units.
 Not stating the range correctly (Write the smallest and largest values of the IV in the spaces
 Poor explanation. If you can see a pattern in your results then the range was suitable, so say the range was big enough
to allow you to see a pattern and not so big the practical took too long. If you can’t see any increase/decrease in the
DV, say it was not big enough to allow you to identify a pattern and test the hypothesis.
2 You have been given a Secondary Data Sheet that provides results from similar investigations.
2 (a) Draw a sketch graph of the results in Case Study 1.
The graph should show how the number of bubbles produced by the pondweed in one minute varies with temperature.
(2 marks)
When marks are dropped it is usually for the line, the axes headings can be copied from the table of results and do not
require units. The line should be either a smooth curve or a straight line drawn with a ruler. If two lines can be seen then
the mark will be lost.
2 (b) A gardener makes this hypothesis:
‘The higher the temperature, the faster photosynthesis will be.’
Look at Case Studies 1, 2 and 3.
Explain whether or not the results in Case Studies 1, 2 and 3 support this hypothesis.
To gain full marks, your explanation should include appropriate examples from the results in Case Studies 1, 2 and 3.
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(3 marks)
Very few candidates get 3 marks here, for one of two reasons.
Either they forget to give examples (e.g. write numbers from the results table) or because they run out of space and have
not given sufficiently detailed explanations of both case studies 2 and 3. There is usually one out of case studies 2 or 3
where the results are irrelevant because the variables are not those of the hypothesis investigated. The other usually
supports the hypothesis but to give a detailed explanation something else is required. e.g. It could be that the results
support the hypothesis in general but the pattern seems to level off for higher values of the independent variable
suggesting that there is a maximum value of the dependent variable.
3 How could the results from your investigation be useful in the context that you have researched?
You may use information from your Candidate Research Notes to help you to answer this question.
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(3 marks)
Few candidates score 3 marks on this question.
You must find some way in which your results can help in the context give. As this question come up every time and the
context is given beforehand, this is definitely an example of a question where planning what you will write before the
exam is likely to gain you at least 1-2 marks.
4 Make sure that you hand in your Candidate Research Notes, results tables and chart or graph with this paper.
You will be awarded up to four marks for your chart or graph.
(4 marks)
If marks are dropped it is generally because of one of a few things.
 Plotting points in the wrong place (choose yourself an easy to use scale)
 Joining the dots rather than drawing a line of best fit (never join the dots unless you know why you are doing it)
 Forgetting to label (with units) the axes
 Having an incorrect scale on axes, e.g. 1 square from 0 to 5 and two squares from 5 to 10.
 Drawing a line of best fit which has lots more points on one side (above/below) than the other.
Questions which don’t generally appear in every paper but have appeared at least
once
1 (b) Describe in detail how you could use repeated readings to obtain more accurate results.
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(3 marks)
Very similar to a question in Section 1 which has a slightly different mark scheme. Make sure you cover all of the points in
BOTH mark schemes.
1 (b) (i) Some members of your class may have done an investigation to test the same hypothesis.
Explain how using the results of other people may help you to decide if your investigation is reproducible.
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(3 marks)
1 (d) Most investigations contain errors or uncertainties.
What do you think was the cause of the largest error or uncertainty in your investigation?
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What could you do to reduce the size of this error or uncertainty if you were to repeat the investigation?
Explain your answer.
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(3 marks)
Marks dropped generally for not stating the obvious in their explanation. E.g. if the error chosen was a measurement error
from using a measuring cylinder with 10ml divisions, the improvement was to use one with 1ml divisions, not saying this
will mean that I can be more precise in measuring the volume of liquid.
2 (c) (ii) Estimate what the extension would be if the force applied was 10 000 newtons.
Give one reason why you cannot be sure that your estimate will be correct.
Ideas from your own investigation may help you to answer this question.
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(3 marks)
Data was given for extension between 0 and 8000N in a graph. Candidate asked to predict (extrapolate) to a higher force
and predict how the line of best fit would continue.
Question 2c generally asks you to look at case study 4 on the sheet and do some of the
following things:
 describe the relationship between the variables, or
 look at how the people who did the experiment have described the relationship and
criticise their work and say whether you agree with it or not, or
 analyse some information and make and justify a prediction
 say what extra evidence would be useful
When marked are dropped on the question it’s usually because of a lack of detail in the answer. To get 3 marks generally
requires a good amount of detail.
2 (c) Look at Case Study 4.
To what extent do the results support the gardener’s hypothesis? Explain your answer.
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(3 marks)
2 (c) Look at Case Study 4.
Use data from Case Study 4 to explain why these results do not support the manufacturer’s hypothesis.
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(3 marks)
2 (c) Look at Case Study 4.
2 (c) (i) Do the results support the manufacturer’s hypothesis?
Explain your answer.
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(3 marks)
3 (a) One of the food manufacturer’s scientists suggests that the results from Case Study 4 are evidence to support a
different hypothesis.
Suggest a different hypothesis that could be made from the data in Case Study 4.
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Explain how the results support the hypothesis you have suggested.
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(3 marks)
A follow up to question 2 (c) which asked you to make up a new hypothesis having discussed why the results of case study
4 do not support the hypothesis.
Other things that may be asked about in either paper
You should make sure that you know the following things in case you get asked about them:
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The independent variable
The dependent variable
A list of control variables (and how you will control them)
What different types of error are (e.g. zero error, random error)
The range and interval of the independent variable you will use
Whether your variables were continuous or categoric variables.
The meanings of the other terms on the yellow sheet in your books