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Slide 2 Frequency Higher frequency = high sound = More waves = shorter wavelength Low frequency = Low sound =Less waves= longer wavelength Slide 3 Period of a Wave The period is the duration of one cycle in a repeating event.duration cycle Frequency is a measure of the number of occurrences of a repeating event per unit time.measuretime Slide 4 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. Slide 5 Energy The amount of energy a wave has determines its amplitude. Slide 6 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. Slide 7 Frequency The frequency at which a string vibrates is its natural frequency The frequencies of an instruments tone that are multiples of the fundamental frequency are overtones. Slide 8 Instruments Brass and wind instruments make sounds by vibrating a column of air. Beats are produced by 2 sound with different frequencies Slide 9 FM FM broadcasting is a broadcast technology invented by Edwin Howard Armstrongbroadcast technologyEdwin Howard Armstrong FM carrier wave frequencies vary from 88 Mhz to 108 Mhz FM = Frequency Modulation Slide 10 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. Slide 11 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. Slide 12 Formulas Slide 13 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