# Wave-a disturbance that transfers energy through matter or space

Wavea disturbance that transfers energy through matter or space; after a wave is gone the matter is back where it started, only the energy has been moved

Two types of waves

Mechanical waves -need a medium; includes sound, ocean, string waves; can be transverse, longitudinal or surface waves

Electromagnetic wavesneed NO medium; include light, radio, x-rays, TV, microwaves; all are transverse

Transverse wave-energy and the wave move perpendicular to each other

Longitudinal wave-energy and wave travel parallel to one another

### Last Physics Equation

• The relationship between wavelength, frequency and wave speed.

### Wavelength

• Greek letter lambda – λ

• The distance between successive identical parts of a wave; one complete wave cycle; measured in distance units

• On a transverse wave-crest to crest, trough-trough or crest-trough

• On a longitudinal wave-compression to compression, rarefaction to rarefaction or compression to rarefaction

### Frequency

• Symbol is a lower case f

• The number of wave cycles that pass a point in a second

• Measured in Hertz (Hz)

• 1 Hz = 1/second

### Wave Speed

• Symbol is a cursive v

• Speed at which a wave travels; depends on medium; fastest in solids and slowest in gasses (think about why)

• Measured in speed units

### Equations in words & symbols

• Wave speed = wavelength x frequency

• V =

λ f

• I will put the wheel on the board and let’s do some sample problems….WATCH

THOSE UNITS!