Properties of Waves

A wave is a disturbance that transfers energy from one place to another without transferring matter. When you drop a stone in water, ripples spread outward carrying energy, but the water particles themselves only move up and down—they don't travel with the wave.

Waves can travel through a medium (like water, air, or solids) or, in the case of electromagnetic waves, through empty space (a vacuum).

Wavelength (λ) is the distance between two adjacent crests (or troughs), or between any two corresponding points on consecutive waves. It's measured in metres (m).

Frequency (f) is the number of complete waves passing a point per second. It's measured in Hertz (Hz), where 1 Hz = 1 wave per second.

Amplitude (A) is the maximum displacement of a particle from its rest position. Larger amplitude means more energy—louder sounds or brighter light.

Period (T) is the time for one complete wave cycle. It's related to frequency by T = 1/f.

Wave speed tells us how fast the wave energy travels. It's calculated using:

If you increase frequency while wavelength stays the same, wave speed increases. If you increase wavelength while frequency stays the same, wave speed also increases.

Transverse waves have particles vibrating perpendicular (at right angles) to the direction of wave travel. Examples include light, water ripples, and seismic S-waves.

Longitudinal waves have particles vibrating parallel to the direction of wave travel. They create regions of compression (particles close together) and rarefaction (particles spread apart). Sound waves and seismic P-waves are longitudinal.