The Energy of Waves

The Energy of Waves

The Nature of Waves Wave Medium periodic disturbance in a solid, liquid, or gas energy being transferred through a medium or empty space substance through which a wave can travel

Mechanical waves waves that require a medium ex. sound waves Electromagnetic waves do not require a medium travel through emptiness of space and matter

Types of Waves Transverse waves 1. Crest 2. Trough particles move perpendicularly to the direction the wave is traveling (up & down) ex. electromagnetic waves highest point on wave lowest point on wave

Longitudinal Waves particles vibrate parallel to the direction of wave motion (back & forth) ex. sound waves 1. Compression particles are pushed together 2. Rarefaction particles are spread apart

Surface Waves Combination of transverse and longitudinal waves Wave motion is circular Example-Ocean Wave

Properties of Waves Amplitude related to height max distance from rest position waves with large amplitude carry more energy

Wavelength distance between two crests or two compressions shorter wavelengths more energy Frequency # of waves in a given time measured in hertz (Hz) 1 Hz 1 wave/sec high frequency more energy

Wave Speed speed at which wave travels speed wavelength x frequency v λxf wavelength and frequency are inversely related

Wave Interactions Reflection wave bounces back after hitting a barrier all waves can reflect Echo reflected sound waves

Refraction bending of a wave as the wave passes from one medium to another at an angle wave speed and wavelength changes ex. rainbows – sunlight refracted through water droplets

Diffraction bending of waves around a barrier or through an opening depends on wavelength and size of barrier ex. sound waves can be heard because they have longer wavelengths than light waves

Interference two or more waves overlapping Constructive Interference waves overlap to make larger crests/troughs – larger amplitude Destructive Interference crest of one wave overlaps the trough of another smaller amplitude waves with same crest/trough no wave at all

Standing Waves Resonance pattern of vibration that simulates a wave that is standing still only looks like it is still ex. musician plucks a guitar string two objects naturally vibrate at the same frequencies ex. singing in the shower