Properties of Waves

• INSANE wave pool in Tokyo. Where's the water? - YouTube

• A wave is a disturbance that transports energy from one location to another without transportation of matter.

Ex: the people in the video did not travel across the pool, instead they moved locally up and down, or oscillated . This motion is very similar to what molecules do when a wave passes through.

The medium is the physical environment through which a wave can travel.

ex: people are a medium for this wave.

Properties of Waves

• Waves that require a medium are called mecahnical waves. Waves in water (or people) are mechanical waves.

• Electromagnetic waves (visible light, radio waves, microwaves, x-rays) can travel through a vacuum, therefore are not classified as mechanical waves.

Properties of Waves

Types of Waves• Pulse wave = a wave that is a single traveling

pulse• Periodic wave = a repeated series of pulse

waves• Sine wave = a special case of a periodic wave

where the wave has a source that vibrates with simple harmonic motion

Properties of Waves

• Transverse Wave = a wave whose particles vibrate perpendicular to the direction the wave is traveling. (ex: people in a wave pool)

• Longitudinal Wave = a wave whose particles vibrate parallel to the direction the wave is traveling. Usually found in density or pressure settings. (ex: sound waves through air)

Properties of Waves

Parts of a wave• Crest = the highest point above the

equilibrium position.• Trough = the lowest point below the

equilibrium position.• Wavelength (λ) = the distance between two

adjacent similar points of a wave (crest to crest or trough to trough).

Properties of WavesTransverse Waves

Longitudinal Waves

Properties of Waves

• One wavelength is when vibrating particles of the medium complete one full cycle. Therefore wave frequency describes the number of waves that pass a given point in a unit of time.

• The period is the time required for one complete cycle of vibrations of the medium’s particles, or for how long it takes one complete wavelength to pass a given point.

Properties of Waves

Equationsv = distance/time = wavelength/period

v = λ/Tf = 1/TTherefore:

v = fλSpeed = frequency * wavelength

Ignore any damping, or decrease in amplitude over time