Term | Definition |
Wave | A disturbance traveling through a medium where energy is transferred from one particle of the medium to another without causing any permanent displacement of the medium itself. |
Medium | The substance or material that carries a wave. Only mechanical waves require a medium. |
Mechanical waves | A wave that is not able to transmit its energy through a vacuum; they require a medium in order to transmit energy. |
Electromagnetic waves | A wave that is able to transmit its energy through a vacuum; they do not require a medium in order to transmit energy. |
Crest | The part of a wave with greatest magnitude; the highest part of a wave. |
Trough | The part of a wave with the least magnitude; the lowest part of a wave. |
Amplitude | One half the full extent of a vibration, oscillation, or wave. |
Wavelength | The distance between one peak or crest of a wave of light, heat, or other energy and the next peak or crest. |
Frequency | The rate at which a repeating event occurs, such as the full cycle of a wave; usually measured in Hertz (Hz). |
Period | The time it takes to complete one cycle. |
Transverse wave | A wave, such as an electromagnetic wave, that is propagated in a direction perpendicular to the direction of displacement of the transmitting field or medium. |
Longitudinal (compression) wave | A wave that is propagated in the same direction as the displacement of the transmitting medium. |
Compression | An increase in density and pressure in a medium, such as air, especially when caused by the passage of a wave, such as a sound wave. |
Rarefaction | A decrease in density and pressure in a medium, such as air, especially when caused by the passage of a wave, such as a sound wave. |
Reflection | The change in direction of a wave, such as a light or sound wave, away from a boundary the wave encounters. |
Refraction | The turning or bending of any wave, such as a light or sound wave, when it passes from one medium into another of different optical density. |
Diffraction | Change in the directions and intensities of a group of waves after passing by an obstacle or through an aperture whose size is approximately the same as the
wavelength of the waves. |
Interference | The pattern of pressure, brightness, amplitude, or other wave characteristic that comes from adding more than one wave of the same kind. |
Constructive interference | Occurs when waves add up to make a larger amplitude. |
Destructive interference | Occurs when waves add up to make a smaller amplitude. |
Absorption | Waves transfer energy to the material and it does not refract or reflect. |
Electromagnetic spectrum | The range of wavelengths or frequencies over which electromagnetic radiation extends. |