waves

waves

travelling disturbances that transport energy from one to location to another without transporting matter

examples of waves

ripples on water surface

vibration in a guitar string

electromagnetic waves - light, radio waves, x-rays, microwaves, IR, UV

seismic waves from earthquakes

medium

a substance to travel through

electromagnetic waves

only waves that can travel through a vacuum (empty space)

mechanical waves

all other waves requiring a medium

• travel large distances but individual particles in medium never move far from their original positions

transverse waves

particles in medium vibrate perpendicular to direction the wave is travelling

positon of particles in transverse waves

When the particles are displaced upwards from their resting position, they reach a maximum positive displacement called a crest or peak.

longitudinal wave

particles in medium vibrate parallel to direction the wave is travelling

compression

regions of high pressure

rarefaction

regions of low pressure

features of waves

1. amplitude

2. wavelength

3. frequency

4. period

5. speed

amplitude (A)

maximum displacement of particle from resting position

• metres

wavelength (λ)

distance over which wave’s shape repeats

• (distance between two crests/troughs

• metres

frequency (f)

number of wave cycles per second

• hertz (hz)

hertz to seconds conversion

1 hz = 1 s^-1

period (T)

amount of time it takes for one complete wavelength to pass a specific point

• seconds

frequency is inverse of period

velocity (v)

v = displacement / time = wavelength / period = wavelength x frequency

• m s^-1