Sound in Solids
Higher Tier Only
- Sound waves are vibrations of molecules
- When a sound wave travelling through a gas or a liquid comes into contact with a solid, some of the energy it is transferring is reflected from the surface of the solid, and some is transmitted through or absorbed by the solid
- A reflected sound wave is called an echo
- Sound is an example of a longitudinal wave, hence it consists of:
- Compressions - regions of higher density
- Rarefactions - regions of lower density
Sound is a longitudinal wave consisting of compressions and rarefactions - these are areas where the pressure of the air varies with the wave
- These compressions and rarefactions cause changes in pressure, which vary in time with the wave
- Therefore, sound is a type of pressure wave
- When the waves hit a solid, the variations in pressure cause the surface of the solid to vibrate in sync with the sound wave
When sound waves hit a solid, the fluctuating pressure causes the solid to vibrate