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Year 7 Science Physical Sciences AC9S7P02

Sound Waves

Sound is a mechanical wave produced by vibrating objects. It travels through materials as a pressure wave.

What You Need to Know

Key Concept Diagram

Sound is created by vibrations that produce pressure waves

Sound needs a medium (solid, liquid, or gas) to travel — it cannot travel through a vacuum

Frequency determines pitch: high frequency = high pitch

Amplitude determines loudness: large amplitude = loud sound

Key Vocabulary

Vibration

Rapid back-and-forth movement that produces sound

Frequency

Number of wave cycles per second, measured in Hertz (Hz)

Amplitude

The height of a wave, related to its energy and loudness

Echo

A sound reflection off a hard surface

Knowledge Check

Select the correct answer for each question. Click "Check Answer" to see if you are right.

Question 1

Why can't sound travel through space (a vacuum)?

Question 2

A high-pitched sound has:

Question 3

Which material does sound travel FASTEST through?

Key Concepts Summary