Unit 3 Waves

Electromagnetic waves

waves that are created from vibrations of an electric or magnetic field

Radio wave

an electromagnetic wave with a low frequency and used in long distance communication

Microwave

an electromagnetic wave with shorter wavelength than a radio wave

infrared wave

an electromagnetic wave that has a wavelength shorter than a microwave

Ultraviolet wave

An electromagnetic wave that has a shorter wavelength than an infrared waves. They are invisible waves that come from the sun.

X-ray wave

An electromagnetic waves used to used to create images of the inside of your body.

Gamma Ray wave

An electromagnetic wave with the smallest wavelength and most energy of any of the waves on the E.M. spectrum. They can be very dangerous.

Transverse wave

A wave that moves up and down, perpendicular to the direction of the wave, and does not need a medium (S-L-G) to travel. Examples: light rays, water waves, and E.M. waves.

Mechanical wave

A longitudinal or compressional wave that moves parallel to the energy of the wave and has compressions and rarefactions. They must have a medium (S-L-G) to travel. Example: sound waves

Medium

A substance (S-L-G solid, liquid, or gas) that can carry a wave from one location to another. Example: water is a medium that carries a waves in the ocean.

Crest

The highest point (peak) of a wave

Trough

The lowest point of a wave

Wavelength

The distance between two corresponding parts of a wave; crest to crest or trough to trough.

Frequency

The number of waves that pass a fixed point in 1 second. Unit is hertz (Hz).

Light wave

The part of the E.M. spectrum that is visible to the eye. Includes ROY G BIV

Amplitude

The height of a wave, measured from line of equilibrium to crest, or line of equilibrium to trough.

Reflection

A property of a light wave where light bounces away from the surface.

Refraction

A property of a light wave where light slows down and bends as it passes from one medium to another.

Diffraction

A property of a wave when an object causes it to change direction and bend around it.

Absorption

when a wave strikes an object and goes into it

Constructive interference

occurs when two or more waves combine to produce a wave with a larger displacement

Destructive interference

occurs when two or more waves combine to produce a wave with a smaller displacement

ROY G BIV

An acronym to remember the 7 colors of visible light: red, orange, yellow, green, blue, indigo, violet

transparent

Allowing all light to pass through (ex. clear glass)

translucent

when some light passes through an object (ex. tinted car window, tissue paper, smoke, fog)

opaque

when no light passes through an object (ex. metal, bricks, wood)

convex lens

having a surface that is curved with the bulge in the middle of the lens

concave lens

A lens that is thinner in the center than at the edges

lens

a transparent substance with curved sides that light passes through

light

a type of energy wave that makes it possible to see

electromagnetic spectrum

All of the frequencies or wavelengths of electromagnetic radiation

reflection (sound)

when sound waves bounce back to you--Echo

refraction (sound)

the bending of a sound wave because it changes speed

diffraction (sound)

a sound wave goes around and object or through an opening (ex. I can hear someone talk around the corner of a building)

echolocation (same as SONAR)

the use of sound waves and echoes to determine where objects are

doppler effect

a change in the frequency of a sound wave as an object moves away from a person

decibel

a unit to measure the loudness or intensity of sound

pitch

the position of a single sound in the complete range of sound (high frequency waves have a higher pitch)

loudness

the intensity of a sound, which is determined by the amplitude (height) of a wave.

sound wave

a mechanical wave that vibrates and must have a medium (SLG) to travel

longitudinal wave

a compressional wave (slinky) that has compressions and rarefactions.

frequency

the number of waves that pass a fixed point in a second

amplitude

the maximum distance from the line of equilibrium to a point on the wave (the height of the wave)

resonance

when 2 different sound waves meet and the wave that it creates is a new vibration

compression

the part of a sound wave that is high frequency and close together

rarefaction

the part of a sound wave that is low frequency and spread apart