What are Waves? A wave is a disturbance that transfers energy from place to place. The material through which a wave travels is called a medium. Ex: Gases (air), liquids, solids Waves that require a medium are called mechanical waves. Not all waves require a medium, these are called electromagnetic waves. Ex: Light from the sun can carry energy through empty space.
How Do Waves Transfer Energy? Mechanical waves travel through a medium, but they do not carry the medium with them. Example: When a wave travels through water, the water moves up and down, but does not carry the water with it But how? All mediums are made of tiny particles. When a wave enters a medium, it transfers energy to a medium’s particles. This causes the particles to bump into each other, passing the wave’s energy along.
Types of waves Waves are classified by how they move. Transverse waves- waves that move the medium at right angles to the direction in which the waves travel
Transverse Waves The high part of a transverse wave is called a crest The low part of a transverse wave is called a trough
Longitudinal Wave Longitudinal waves move the medium parallel to the direction in which the waves travel.
Longitudinal Waves Compression- area of longitudinal wave where the coils are close together Rarefaction- area of longitudinal wave where the coils are spread out, or rarefied
Properties of Waves Amplitude – the maximum distance the particles of the medium carrying a wave move away from their rest position. Wavelength – the distance between two corresponding parts of a wave. (crest-to-crest, trough- to-trough) Frequency – the number of complete waves that pass a given point in a certain amount of time. Speed – how far the wave travels in one unit of time.
Formulas Speed = wavelength x frequency (S = W x F) Frequency = Speed / Wavelength (F = S / W) Wavelength = Speed / Frequency (W = S /F)