WavesMany different kinds of waves

What exactly is a wave

• A wave is a disturbance that transfers energy

• Doesn’t transfer the particles of the material only the energy

Medium

• The material a wave travels through • Mechanical waves need a medium

• Water gas and solids can be mediums

Mechanical wave

• Mechanical waves need a medium in order to transfer energy.

• Sound waves are mechanical waves – energy moves through the air

• Seismic waves – energy moves through the Earth

Electromagnetic waves

• Electromagnetic waves do not need a medium to transfer energy – can go through a vacuum.

• Light waves and radio waves are examples

Transverse waves

• In transverse waves – energy moves perpendicular to the motion (direction) of the wave

Longitudinal waves

• In longitudinal waves energy moves parallel to the motion (direction)

• Sound waves are longitudinal

crest

• The crest is the highest point of a transverse wave – draw this in your notes

trough

• Troughs are the lowest point in a transverse wave – draw this in your notes

amplitude

• The greatest distance particles vibrate form resting to crest or resting to trough or I/2 the distance from the very top of one crest to the very bottom of the next trough – draw and label this in your notes

wavelength

• The distance between any two identical parts of a wave. Crest to crest or trough to trough

• Draw and label this in your notes

Period – the time it takes T = 1/f

• Period is how long between crests or the total time for one vibration. If you count 4 seconds between crests, then the period is 4

Frequency (how often) f = 1/T

• How many full wave lengths pass a point in a given period of time. If you count 3 wavelength in 1 second then the frequency is 3 hertz. Hertz is the unit for frequency. The shorter the wavelength the higher the frequency.

Wave speed

• The speed of a wave depends on the medium it is traveling through. Gass is the slowest, liquid is the next and a wave travels fastest in a solid.

• The formula is v= f times wavelenth (λ)• or v =f λ

Formulas you will need

• F = 1/T T = 1/f

Wavelength (λ) = v/f

V = f λ

F = v/λ