-- Core –

✔

Describe the production of sound by vibrating sources.

Describe the longitudinal nature of sound waves.

State the approximate range of frequencies audible to humans as 20 Hz to 20 000 Hz.

Know that a medium is needed to transmit sound waves.

Know that the speed of sound in air is approximately 330–350 m/s.

Describe a method involving a measurement of distance and time for determining the speed of sound in air.

Describe how changes in amplitude and frequency affect the loudness and pitch of sound waves.

Describe an echo as the reflection of sound waves.

Define ultrasound as sound with a frequency higher than 20 kHz.

-- Extended –

✔

Describe compression and rarefaction.

Know that, in general, sound travels faster in solids than in liquids and faster in liquids than in gases.

Describe the uses of ultrasound in non-destructive testing of materials, medical scanning of soft tissue and sonar including calculation of depth or distance from time and wave speed.