AQA · GCSE · Combined Science
Course version: 8464 · Version from Sept 2018
The Earth's early atmosphere: Students should be able to, given appropriate information, interpret evidence and evaluate different theories about the Earth’s early atmosphere.
Scientists use evidence such as ancient rock layers, isotopic ratios, and the atmospheric composition of planets like Venus and Mars to build theories about the Earth's early atmosphere.
- 3 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
Scientists use evidence such as ancient rock layers, isotopic ratios, and the atmospheric composition of planets like Venus and Mars to build theories about the Earth's early atmosphere. Because no one was present to measure it directly billions of years ago, several theories exist and each must be judged against available evidence. Interpreting evidence means explaining what data suggests about past conditions. Evaluating theories means comparing how well each theory fits the evidence, considering strengths and limitations. For example, if a rock sample contains ancient carbonate sediments, that supports a theory in which carbon dioxide dissolved in early oceans. A theory that conflicts with measured data is weaker. You should use the information given, not memorised theories, to reach a justified conclusion.
What earns the marks
- Identify the relevant evidence provided in the question and state what it indicates about the early atmosphere.
- Compare different theories by matching each to the specific evidence that supports or contradicts it.
- Discuss the strengths and weaknesses of the theories, including limitations such as incomplete or indirect evidence.
- Use the provided information, rather than relying solely on recalled theories, to reach a logically justified conclusion.
Common mistakes and how to put them right
Ignoring the supplied information and writing a memorised theory.
Put it right by basing every point on the specific evidence provided in the question.
Treating one piece of evidence as absolute proof.
Put it right by explaining that evidence supports a theory but may not prove it conclusively due to the vast time scale.
Listing theories without comparing them.
Put it right: Explicitly stating which theory fits the evidence better and explaining why.
Exam tips
- Read the provided information carefully and underline the key pieces of evidence before planning your answer.
- Use comparative language such as 'supports', 'contradicts', 'more likely', and 'less likely' when evaluating competing theories.
Try the lesson
The start of the The Earth's early atmosphere: Students should be able to, given appropriate information, interpret evidence and evaluate different theories about the Earth’s early atmosphere. lesson, made from checked teaching notes for this specification point.
Have a go first
A scientist claims that the early atmosphere of the Earth was mostly carbon dioxide. Which piece of evidence would best support this claim?
Listen
Scientists use evidence such as ancient rock layers, isotopic ratios, and the atmospheric composition of planets like Venus and Mars to build theories about the Earth's early atmosphere. Because no one was present to measure it directly billions of years ago, several theories exist and each must be judged against available evidence. Interpreting evidence means explaining what data suggests about past conditions. Evaluating theories means comparing how well each theory fits the evidence, considering strengths and limitations. For example, if a rock sample contains ancient carbonate sediments, that supports a theory in which carbon dioxide dissolved in early oceans. A theory that conflicts with measured data is weaker. You should use the information given, not memorised theories, to reach a justified conclusion. A strong answer earns marks for these points. Identify the relevant evidence provided in the question and state what it indicates about the early atmosphere. Compare different theories by matching each to the specific evidence that supports or contradicts it. Discuss the strengths and weaknesses of the theories, including limitations such as incomplete or indirect evidence. Use the provided information, rather than relying solely on recalled theories, to reach a logically justified conclusion. A common slip: Ignoring the supplied information and writing a memorised theory. Instead, basing every point on the specific evidence provided in the question. Exam tip: Read the provided information carefully and underline the key pieces of evidence before planning your answer.
Key words
Say what each word means before you turn the card.
Interpreting evidence
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Evaluating theories
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Limitations of indirect evidence
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See every definition
- Interpreting evidence
- Explaining what data suggests about past conditions, such as what a rock sample indicates about the early atmosphere.
- Evaluating theories
- Comparing how well each theory fits the evidence, considering strengths and limitations, and stating which fits better and why.
- Limitations of indirect evidence
- Evidence supports a theory but may not prove it conclusively, including because of incomplete or indirect evidence and the vast time scale.
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