Sound

What the syllabus asks of you

• Describe the production of sound by vibrating sources
• Describe the longitudinal nature of sound 10 Describe compression and rarefaction 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 11 Know that, in general, sound travels faster in
• Know that the speed of sound in air is solids than in liquids and faster in liquids than in approximately 330–350 m / s gases continued Core Supplement
• 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 12 Describe the uses of ultrasound in non- higher than 20 kHz destructive testing of materials, medical scanning of soft tissue and sonar including calculation of depth or distance from time and wave speed