AQA · GCSE · Combined Science
Course version: 8464 · Version from Sept 2018
Speed: A typical value for the speed of sound in air is 330 m/s.
Sound is a wave that travels through a medium by making particles vibrate.
Checked against the AQA 8464 specification (opens in a new tab) on .
- Point 10 of 18
- 4 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
Sound is a wave that travels through a medium by making particles vibrate. In air near room temperature, a typical value for its speed is 330 m/s, which is about one million times slower than light. This value is typical rather than exact because the speed of sound in air increases as the temperature rises and changes slightly with humidity. You can use 330 m/s in calculations, for example to estimate the distance to a lightning strike: if thunder is heard 3 s after the flash, the sound has travelled about 330 m/s × 3 s = 990 m. Remember that sound cannot travel through a vacuum, and that it travels faster in liquids and solids than in gases because the particles are closer together.
What earns the marks
- State that sound is a wave that travels through a medium and cannot travel through a vacuum.
- Quote a typical value for the speed of sound in air as 330 m/s.
- Explain that 330 m/s is typical rather than exact because temperature and other conditions affect the speed.
- Use speed = distance ÷ time with 330 m/s to calculate a distance or time, for example the distance to a lightning strike.
- Compare the speed of sound in air with its speed in liquids and solids, where it is greater.
Common mistakes and how to put them right
Writing 330 m/s as the exact speed of sound in every situation.
Put it right by describing it as a typical value for air near room temperature.
Forgetting to convert a time in milliseconds to seconds before using speed = distance ÷ time.
Put it right by converting to seconds first.
Confusing the speed of sound with the speed of light.
Put it right by noting that light travels much faster, which is why lightning is seen before thunder is heard.
Exam tips
- Learn the typical value 330 m/s for sound in air and use it when a question asks for an estimate.
- Write down the equation, substitute the values with units, and round your answer sensibly for an estimate.
- If a question asks why the value is only typical, refer to temperature or to the medium rather than saying it is random.
Try the lesson
The start of the Speed: A typical value for the speed of sound in air is 330 m/s. lesson, made from checked teaching notes for this specification point.
Have a go first
What is a typical value for the speed of sound in air?
Listen
Sound is a wave that travels through a medium by making particles vibrate. In air near room temperature, a typical value for its speed is 330 m/s, which is about one million times slower than light. This value is typical rather than exact because the speed of sound in air increases as the temperature rises and changes slightly with humidity. You can use 330 m/s in calculations, for example to estimate the distance to a lightning strike: if thunder is heard 3 s after the flash, the sound has travelled about 330 m/s × 3 s = 990 m. Remember that sound cannot travel through a vacuum, and that it travels faster in liquids and solids than in gases because the particles are closer together. A strong answer earns marks for these points. State that sound is a wave that travels through a medium and cannot travel through a vacuum. Quote a typical value for the speed of sound in air as 330 m/s. Explain that 330 m/s is typical rather than exact because temperature and other conditions affect the speed. Use speed = distance ÷ time with 330 m/s to calculate a distance or time, for example the distance to a lightning strike. A common slip: Writing 330 m/s as the exact speed of sound in every situation. Instead, describing it as a typical value for air near room temperature. Exam tip: Learn the typical value 330 m/s for sound in air and use it when a question asks for an estimate.
Key words
Say what each word means before you turn the card.
Speed of sound in air
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Medium
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Speed equation
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Temperature
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See every definition
- Speed of sound in air
- A typical value for the speed of sound in air is 330 m/s, which is typical rather than exact.
- Medium
- Sound is a wave that travels through a medium by making particles vibrate, and it cannot travel through a vacuum.
- Speed equation
- Speed = distance ÷ time can be used with 330 m/s to calculate a distance or time, for example the distance to a lightning strike.
- Temperature
- The speed of sound in air increases as the temperature rises, so 330 m/s is typical rather than exact.
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