Waves and sound

Wave

An oscillation that carries energy from one place to another

Transverse wave

Oscillates perpendicular to the direction of energy transfer eg light

Longitudinal wave

Oscillation is parallel to the direction of energy transfer eg sound

Wave length

The distance from one point on a wave to the equivalent position on the next

Frequency

Number of oscillations per second

Period

Time for one complete oscillation

Amplitude

Maximum distance of a point on a wave from it's rest position

measure velocity of sound in air

Stand far away from a large reflecting wall and measure the distance using a measuring tape. Make a loud sound and use a stop watch to measure the time between making the sound and hearing the echo. Repeat and take an average. Half the time.

Measure the velocity of water ripples

Use a bar to make ripples in a water tank. Use a stop watch to time how long it takes for the ripple to reach the end of the tank. Measure the distance the wave travel. Calculate speed

Infrasound

Longitudinal sound wave with frequency below 20Hz. It is used for animal communication/detection , earthquake detection, meteor detection

Ultrasound

Longitudinal sound wave with frequency above 20 000Hz. It is used for sonar equipments to find the depth of the sea, ultasound scans, animals such as bats

Seismic waves

P waves are longitudinal and travel faster through solid and liquid but s waves are transverse and travel more slowly through only solid.