Sound Waves
Sound is a longitudinal wave produced by vibrations that travels through a medium such as air, liquid or solid.
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Sound is a longitudinal wave produced by vibrations that travels through a medium such as air, liquid or solid.
- It cannot travel in a vacuum
- Speed in air is about 340 metres per second
- Sound travels faster in solids
🧠 Quick quiz
Three questions. Score 2 or more to complete the topic.
What is Sound Waves?
Within Physics, which covers forces, energy, waves, electricity, magnetism, light and space explained through motion and experiments, this topic explains Sound Waves. Physics topics explain how things move, push, heat up and carry energy, so each one here pairs a definition with a live model you can change.
Check that you can explain Sound Waves in your own words and give one example from everyday life. If you can do that, you have understood the core idea.
Understanding Sound Waves explains how the physical world behaves, from sport and transport to electricity and medicine.
Sound Waves in detail
Sound is a longitudinal wave produced by vibrations, which pass through a medium by compressions and rarefactions. It needs a medium, so it cannot travel through a vacuum. The speed is about 340 m/s in air, about 1,500 m/s in water and over 5,000 m/s in steel, since particles are closer together in denser media.
Sound can be reflected, refracted and diffracted. Humans hear frequencies from about 20 Hz to 20,000 Hz. An oscilloscope can display sound waves, showing amplitude and frequency. Sound is used in music, communication, medicine and engineering.
How the interactive helps you understand Sound Waves
Watch the wave in the interactive. Use any sliders or buttons it offers to change the values and see how the wave responds.
Before you change anything, predict the result. Then change one value at a time and check whether your prediction was right. This is a quick way to build a correct mental model of Sound Waves.
Real-life uses and examples
- Predict what a ball, car or circuit will do with Sound Waves before you do the calculation.
- Explain everyday devices, such as brakes, lifts or chargers, using Sound Waves.
- Use Sound Waves to make sense of a practical and its results.
Common mistakes to avoid
- Mixing up Sound Waves with a related quantity that has different units.
- Forgetting that some quantities, such as force or velocity, also have a direction.
- Learning the definition without testing it. Use the quiz and the interactive to check that you can apply the idea.
Frequently asked questions about Sound Waves
What is Sound Waves?
Sound is a longitudinal wave produced by vibrations that travels through a medium such as air, liquid or solid.
What are the most important points about Sound Waves?
The main points are: It cannot travel in a vacuum; Speed in air is about 340 metres per second; Sound travels faster in solids.
Why is Sound Waves useful?
Understanding Sound Waves explains how the physical world behaves, from sport and transport to electricity and medicine.
How can I practise Sound Waves?
Open the interactive at the top of this page and change the controls one at a time. Predict the result before each change, then take the three-question quiz. A score of two or more marks the topic as complete on this device.
Which topics are related to Sound Waves?
Related topics in Physics include Light and Reflection, Lenses, Electromagnetic Spectrum.