Waves for detection and exploration: Waves

Ultrasound

Sound waves that have a frequency higher than the upper limit for human hearing (above 20,000 Hz)

Uses of ultrasound

breaking kidney stones, cleaning jewellery, ultrasound scans, echo sounding

Using ultrasound for breaking kidney stones and cleaning jewellery

The vibrations caused by the ultrasound waves shake apart the dirt or kidney stones and break them up

Using ultrasound waves for imaging

The waves are partially reflected when they meet a boundary between two materials and the time taken for the reflected waves to reach a detector can be used to determine how far away the boundary is

Seismic waves

Waves produced by earthquakes

P-waves

Longitudinal, seismic waves

S-waves

Transverse, seismic waves that cannot travel through a liquid

How P-waves travel

P-waves are faster than S-waves and can travel through solids and liquids

How S-waves travel

S-waves are slower than P -waves and can only travel through a solid

Uses of seismic waves

P-waves and S-waves provide evidence for the structure and size of the Earth’s core

Echo sounding

When high frequency sound waves are used to detect objects in deep water and measure water depth.

Echolocation

A similar method to echo sounding that animals such as bats and dolphins use to detect their surroundings and to find food