What is a Wave? A wave is any disturbance that transmits energy. Whether a sound wave, water wave, or earthquake wave.

Two Wave Categories Mechanical waves Electromagnetic waves These waves require a medium, gas liquid, or solid to travel through. The wave bumps into a particle (ie air molecule) causing it to vibrate and bump the next particle allowing the wave to travel. Electromagnetic waves These waves do not require a medium, they can travel through space. Visible light is a transverse wave that can travel through space (ie from the Sun to Earth)

Two Types of Waves Transverse: wave pulse moves at a right angle to wave direction. Longitudinal: wave pulse moves along the same axis as the wave direction

Parts of a Transverse Wave Amplitude height of a wave. More energy or more displacement = more height. Crest maximum amplitude Trough minimum amplitude Wavelength The distance between two wave troughs or two wave crests

Parts of a Longitudinal Wave Compression Areas where the wave bunches up (this is maximum amplitude or maximum energy) Rarefaction Areas where the wave stretches out (this is minimum amplitude or minimum energy)

Wave Train A wave train is a series of individual wave cycles The picture to the right shows a wave train made of 2 ½ wave cycles The picture below shows a wave train made of 6 wave cycles

Frequency, Period, Amplitude Frequency (f) is the number of wave cycles per seconds. Greater frequency means higher pitch sound Period (T) is the time for one wave cycle T=1/f and f=1/T Amplitude is the height of the wave. Greater amplitude means greater energy or displacement

Frequency and Pitch Pitch is how “squeaky” a sound is. The higher the frequency, the higher the pitch and the more “squeaky” a sound is. A mouse squeak is a high pitched sound. The lower the frequency, the lower the pitch and the less “squeaky” a sound is. A rumble of thunder is a low pitched sound.