OCR GCSE Chemistry B (Twenty First Century)
OCR GCSE Chemistry B C7 Ideas about Science Exam Questions
Free OCR GCSE Chemistry B revision for C7 Ideas about Science: what you need to know, common mistakes and exam-style questions with answers. Covers planning investigations, variables, risk, analysing data, uncertainty, outliers, correlation and cause, developing explanations, peer review and science in society.
Practise C7 Ideas about Science with past papers
Once you have learnt this topic, find the C7 Ideas about Science questions in real OCR GCSE Chemistry B past papers and mark them with the mark scheme. Doing lots of real questions is the quickest way to learn how examiners ask about each idea.
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About OCR GCSE Chemistry B C7 Ideas about Science
Chapter C7 Ideas about Science runs through the whole OCR Chemistry B course. It is not a separate block of facts but a set of ideas about how science works, assessed in the context of any chemistry chapter. You learn how to plan a fair investigation and assess risk, how to process and evaluate data, how scientific explanations and models are developed and tested, and how science and technology affect society. Questions often use unfamiliar contexts and data, so these skills can earn marks across every topic. Examiners test variables, means, uncertainty, outliers and the difference between correlation and cause.
What you need to know
- IaS1 Investigating Identify the independent variable you change, the dependent variable you measure and the control variables kept the same. A hypothesis is a testable explanation, and a risk assessment identifies hazards and how to reduce them.
- IaS2 Data and uncertainty Repeat measurements to calculate a mean and to spot outliers. The range of repeat readings shows the spread, and uncertainty can be estimated as half the range. Resolution is the smallest change an instrument can detect.
- IaS2 Conclusions A correlation between two variables does not prove that one causes the other; you need a plausible mechanism. Conclusions should be supported by the data and should not go beyond the range tested.
- IaS3 Explanations and models Scientific explanations are tested by making predictions and comparing them with data. Models, such as the particle model or atomic models in C2, have limitations and change when new evidence appears. Peer review checks work before publication.
- IaS4 Science and society Technologies bring benefits and risks; decisions consider the size of the risk, who benefits and who bears the cost, as well as ethical, economic and environmental issues. Sustainability means meeting present needs without harming future generations.
Common mistakes in C7 Ideas about Science
- Saying repeating an experiment makes results accurate. Repeating improves reliability and helps spot outliers; accuracy depends on how close results are to the true value.
- Including an outlier in the mean without comment. Identify it, explain why it is anomalous and leave it out of the mean.
- Claiming a correlation proves cause. State that a mechanism is needed and other factors may be involved.
- Giving vague control variables like 'same amount'. Say exactly what is controlled, such as the same volume and concentration of acid.
- Quoting a mean to far more decimal places than the readings. Match the precision of the raw data.
Try three C7 Ideas about Science exam-style questions
1. A student measures the time for a reaction four times: 24 s, 26 s, 25 s and 35 s. Identify the outlier and calculate the mean of the remaining results. (2 marks)
Show the mark scheme answer
35 s is the outlier; mean = (24 + 26 + 25) / 3 = 25 s.
2. A student investigates how the concentration of acid affects the rate of reaction with magnesium. Name the independent variable, the dependent variable and one control variable. (3 marks)
Show the mark scheme answer
Independent: concentration of acid; dependent: rate, for example volume of gas per minute or time for magnesium to disappear; control: temperature, volume of acid, or mass or surface area of magnesium.
3. Explain why a new scientific claim is peer reviewed before it is published. (2 marks)
Show the mark scheme answer
Other scientists check the methods, data and conclusions; to find errors or flaws and make sure the claim is valid before it is widely accepted.
C7 Ideas about Science FAQs
What does OCR Chemistry B C7 Ideas about Science cover?
It covers planning investigations, handling data and uncertainty, drawing valid conclusions, how scientific explanations and models develop, and how science affects society. It is assessed in the context of chemistry content.
Which paper is it examined in?
Ideas about Science is assessed across both papers, Breadth in chemistry and Depth in chemistry, using contexts from any chapter.
How do I revise Ideas about Science?
Practise on past paper data questions: name variables, calculate means, identify outliers, estimate uncertainty and explain whether data support a conclusion.
