# 15-16 Quiz

## 37 terms · Waves and sound

### mechanical waves

waves that require a medium

### electromagnetic waves

waves that don't require a medium

### longitudinal wave

mechanical wave that causes the medium to travel parallel to wave's movement

### transverse wave

mechanical wave that causes the medium to travel at a right angle to wave's movement

### What causes a mechanical wave?

source of energy causes a medium to vibrate

### crest

high point on a transverse wave

### trough

low point on a transverse wave

### compression

particles of longitudinal wave are close wave

### rarefraction

particles of longitudinal wave are far apart

### What are the four properties of waves?

amplitude, frequency,speed, and wavelength

### wavelength

distance between two corresponding parts of a wave

### amplitude

maximum distance wave moves from rest position

### speed

distance wave travels in a given amount of time

### frequency

amount of complete waves that pass a given point in a certain amount of time

### Hertz

unit for frequency

### Reflection

when a wave or object hits a surface it can't pass through and bounces back

### refraction

occurs when a wave enters a new medium at an angle. One side changes speed before the other, so the wave bends

### diffraction

wave moves around a barrier or through an opening in a barrier, bends and spreads out

### Interference

when two waves meet

### Standing wave

when incoming wave and reflected wave have just the right frequency, they produce a wave that appears to stand still

### node

part of a standing wave that has zero amplitude

### antinode

part of a standing wave that has maximum amplitude

### sound

travels through a medium as a longitudinal wave

### echo

reflected sound wave

### elasticity

ability of a material to bounce back after being disturbed

### density

how much matter or mass there is in a given space or volume

### loudness

perception of energy of a sound

### intensity

amount of energy a sound wave carries per second through a unit area

### decibel

unit to compare loudness of sounds

### pitch

description of how high or low the sound seems to a person

### ultrasound

frequencies above normal human range.
greater than 20,000 Hz

### infrasound

frequencies below normal human range.
less than 20 Hz

### Doppler effect

change in frequency of a wave as its source moves in relation to a observer

### resonance

occurs when one object causes a nearby object to vibrate at a natural frequency

### music

notes combined in patterns that are pleasing

### noise

have no pleasing patterns

### Causes of hearing loss

old age, prolonged exposure to loud noise, infections