I) How Waves Move Energy

A) Waves

1) A wave is a disturbance that travels through matter or space, carrying energy from one place to another without carrying matter along with it

a) Light and sound are both energy traveling in waves

b) Radio waves carry information received by radio and television

2) Waves that travel through water are mechanical waves

a) Mechanical waves need matter to travel through

b) The matter moves back and forth or up and down, however never permanently displaced

c) Example: floating object will only bob up and down, not move forward

d) Waves do not transport matter, only energy

3) Parts of a Wave

a) Crest: the highest part of the waves

b) Trough: the lowest part of the waves

c) Height: vertical distance between the crest and trough

d) Amplitude: the distance any point on the waves is moved from its resting position to the crest (1/2 the distance of the height)

e) Wavelength: the distance between from one crest to the next crest

B) Different Kinds of Waves

1) Transverse Waves: Wave that vibrate at right angles to the direction of the wave

a) Stringed instrument like guitars form transverse waves when plucked

b) Light travels as a transverse wave

c) Do not need a medium to travel through, like light in space

2) Longitudinal Waves: vibrate back and forth in the same direction as the wave is moving

a) Has an area of compression where the particles are closer together

b) Has an area of rarefaction where the particles are spread out

c) Examples include Sound and Earthquake Waves

C) Speed, Frequency and Wavelength

1) The speed of a wave in a particular substance stays the same unless the substance is changed in some way such as heat or density.

a) Sound always travels through air at the same speed unless the temperature changes

b) Waves travel through water at the same speed unless the depth of the water changes

2) Frequency of a wave is the number of vibrations it has in a given time

a) Measured by counting the number of crests that pass a point in a given amount of time

b) 1hertz = 1 vibration per second

D) Energy from Waves

1) All waves carry energy in the form of light, sound, heat, or motion

2) We can use that energy that waves carry

a) Solar panels collect energy from the sun, changing it to heat or electricity

b) Can also get energy from ocean waves

3) Energy in waves can also destroy

a) Hurricane can transfer energy to ocean waves called storm surge

b) Earthquakes energy travels as wave though the earth called seismic waves

c) Undersea earthquakes transfer their energy to the ocean creating tsunamis