AQA · GCSE · Physics
Course version: 8463 · Version from Sept 2016
Students should recognise and be able to use the symbol ≈ that indicates…
Full specification wording
Newton's Second Law: Students should recognise and be able to use the symbol ≈ that indicates an approximate value or approximate answer.
In physics, exact values are not always known or required, particularly when dealing with order-of-magnitude estimations.
Checked against the AQA 8463 specification (opens in a new tab) on .
- Point 10 of 11
- 4 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
In physics, exact values are not always known or required, particularly when dealing with order-of-magnitude estimations. The symbol ≈ indicates that two values are approximately equal. You will encounter this symbol when a question provides or asks for an estimate rather than a precise calculation. For example, the typical walking speed of a person can be written as v ≈ 1.5 m/s, showing it is a reasonable estimate rather than an exact universal constant. Recognising this symbol helps you understand that a question requires you to apply typical everyday values. Standard calculations rounded to an appropriate number of significant figures should still use the standard equals sign.
What earns the marks
- Identify the ≈ symbol as meaning 'approximately equal to' in the context of estimations.
- Interpret given data containing the ≈ symbol as an indication to use an estimated or typical value.
- Apply the ≈ symbol correctly when stating an estimated physical quantity, such as writing v ≈ 1.5 m/s for walking speed.
- Distinguish between the approximate equals sign in an expression like x ≈ 5 and the proportionality symbol in an expression like a ∝ F.
Common mistakes and how to put them right
Believing that the ≈ symbol must be used every time a calculated answer is rounded to significant figures.
Put it right: The standard equals sign is perfectly acceptable and expected when providing a rounded calculated answer.
Confusing the approximate equals sign with the proportionality symbol.
Put it right: Recognise that an expression like y ≈ 10 means approximately equal to, whereas y ∝ x indicates how one variable changes with respect to another.
Writing the ≈ symbol without a numerical value or variable on the right-hand side.
Put it right: Ensure the symbol always sits between two quantities, such as writing v ≈ 3 m/s rather than leaving the relation empty.
Exam tips
- Look out for the ≈ symbol in question stems, as it often hints that you should use typical estimated values rather than performing a precise calculation.
- When asked to estimate a value from your own knowledge, you can write the ≈ symbol before your numerical answer to demonstrate your understanding of approximation.
Try the lesson
The start of the Newton's Second Law: Students should recognise and be able to use the symbol ≈ that indicates an approximate value or approximate answer. lesson, made from checked teaching notes for this specification point.
Have a go first
Which statement correctly describes the meaning of the symbol ≈ when it is written between two values?
Listen
In physics, exact values are not always known or required, particularly when dealing with order-of-magnitude estimations. The symbol ≈ indicates that two values are approximately equal. You will encounter this symbol when a question provides or asks for an estimate rather than a precise calculation. For example, the typical walking speed of a person can be written as v ≈ 1.5 m/s, showing it is a reasonable estimate rather than an exact universal constant. Recognising this symbol helps you understand that a question requires you to apply typical everyday values. Standard calculations rounded to an appropriate number of significant figures should still use the standard equals sign. A strong answer earns marks for these points. Identify the ≈ symbol as meaning 'approximately equal to' in the context of estimations. Interpret given data containing the ≈ symbol as an indication to use an estimated or typical value. Apply the ≈ symbol correctly when stating an estimated physical quantity, such as writing v ≈ 1.5 m/s for walking speed. Distinguish between the approximate equals sign in an expression like x ≈ 5 and the proportionality symbol in an expression like a ∝ F. A common slip: Believing that the ≈ symbol must be used every time a calculated answer is rounded to significant figures. Instead, the standard equals sign is perfectly acceptable and expected when providing a rounded calculated answer. Exam tip: Look out for the ≈ symbol in question stems, as it often hints that you should use typical estimated values rather than performing a precise calculation.
See it
Key words
Say what each word means before you turn the card.
≈
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Estimation
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Standard equals sign
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Proportionality symbol
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See every definition
- ≈
- The symbol that indicates an approximate value or approximate answer, meaning 'approximately equal to'.
- Estimation
- Using an estimated or typical value rather than a precise calculation, as when a question provides or asks for an estimate.
- Standard equals sign
- The sign used for standard calculations rounded to an appropriate number of significant figures, rather than for approximations.
- Proportionality symbol
- The symbol in an expression like a ∝ F, which indicates how one variable changes with respect to another.
Label the diagram
Some boxes have lost their names. Pick the right name for each number.
1Box 1
2Box 2
3Box 3
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