Waves Notes

Waves - chains of vibrating molecules transferring energy from one place to another.

The two types of waves are mechanical waves and electromagnetic waves.

Examples of Mechanical Waves:

• Water waves

• Sound waves

• Seismic waves

• Slinky waves

Mechanical waves - waves that require a medium or something to pass through.

Water waves - move through water molecules.

Sound waves - pass through air, water, or solids (a wall).

Seismic waves - pass through the ground.

Slinky waves - move through an individual loop.

Examples of Electromagnetic Waves:

• Light waves

• Radio waves

Electromagnetic waves - waves that do not need a medium to travel through; they can travel through empty space.

Light waves - light waves from the sun can reach earth from outer space.

Radio waves - allow communication between space crafts.

Transverse waves - waves that move energy along at right angles or perpendicular to the direction of energy flow. Ex: Ocean (water and seismic waves) and electromagnetic waves travel in a transverse pattern.

Compression/ Longitudinal waves - waves that move energy in the same direction as the energy of the wave. Ex: Sound waves, slinky waves: if you compress one part of a slinky and let it go, it will move left to right.

When waves transfer energy from one place to another, only energy is transferred, and not matter.

Crest - the highest part of a wave.

Trough - the lowest part of a wave.

Amplitude - the midpoint between the crest and the trough; the measure of the energy of a wave.

Wavelength - the distance a wave travels from crest to crest or trough to trough.

Frequency - the number of waves passing in one second measured in hertz (waves per second).

A wave with a short wavelength will have a high frequency.

A wave with a long wavelength will have a low frequency.