YR 8 EOY EXAM REVISION - waves

A wave

a vibration that transfers energy

What devices display waves on screens?

Oscillioscope

Wavelength

the distance between a point of a wave to the same point on the next wave

peak or crest

the top of a wave

trough

the bottom of a wave

amplitude

the distance from the middle to the crest or trough of a wave

frequency

the number of waves that travel past a point every second. Measured in hertz.

Compression

when the particles in a wave are close together

Rarefaction

When the particles in a wave are far apart

longitudinal waves

Oscillations that occur parallel to the direction of travel

transverse waves

when the oscillations are perpendicular to the direction of travel

superposition

when waves are added together or cancel each other out

wave speed

frequency X wavelength

the focus of an earthquake

where it originates

the epicentre on an earthquake

the point on the Earth’s crust right above the focus

What scale measures earthquakes

the ricthter scale

Ultrasount

sounds that have a frequency above 20,000hz

Infrasound

Sounds that have a frequency below 20hz

Ossicles

three very small bones that amplify sounds

hammer

an ossicle that touches the eardrum

the anvil

an ossicle that touches the hammer

the stirrup

an ossicle that transmits sounds to the cochlea

The cornea

focuses light into the eye

the pupil

lets light enter through, changes size depending on how much light there is

the retina

the back of the eye, where light is focused

the optic nerve

connects the eye to the brain