Frequency

Higher frequency = high sound = More waves = shorter wavelength

• Low frequency = Low sound =Less waves= longer wavelength

Period of a Wave

• The period is the duration of one cycle in a repeating event.

• Frequency is a measure of the number of occurrences of a repeating event per unit time.

Vibrations• Sound is caused by vibrations

• Sound requires a medium (does not happen in outer space since it is a vacuum.)

• Sound will travel through water at 20 degrees Celsius slower than water at 80 degrees Celsius.

Energy• The amount of energy a wave has

determines it’s amplitude.

Sound

• The unit used to measure sound intensity is the decibel.

• Pitch is how high or low a sound seems to be.

• When a person moves toward a sound, the compressions of the wave are pushed together.

Frequency

• The frequency at which a string vibrates is its natural frequency

• The frequencies of an instrument’s tone that are multiples of the fundamental frequency are overtones.

Instruments• Brass and wind instruments make

sounds by vibrating a column of air.

• Beats are produced by 2 sound with different frequencies

FM

• FM broadcasting is a broadcast technology invented by Edwin Howard Armstrong

• FM carrier wave frequencies vary from 88 Mhz to 108 Mhz

• FM = Frequency Modulation

Radio

• Each radio station broadcasts on one frequency called a carrier wave.

• Information can be added to a radio carrier wave by frequency modulation and amplitude modulation.

Sound

• Violins, harps, and guitars produce sound by vibrating strings.

• A flute player changes the length of a column of air by opening and closing holes which helps make each different sound.

Formulas

Formula Practice• The frequency is 30. What is the

period of the wave.

1/30

The period is 10, what is the frequency of the wave?

1/10