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Light and Waves
Vocabulary for Unit 2: Light and Waves
Term | Definition |
---|---|
Wave | A disturbance that transfers energy from one place to another |
Medium | The material through which a wave travels |
Longitudinal Wave | In this, particles move back and forth in the same direction of the wave, or parallel to the wave. |
Transverse Wave | In this, particles move perpendicular to the direction the wave travels. |
Mechanical Wave | This kind of wave requires a medium to travel through. Examples include water waves and earthquakes. |
Electromagnetic Wave | A type of transverse wave that occurs as a disturbance in electric and magnetic fields. Examples include visible light, radio waves, microwaves, UV light, and x-rays. |
Wavelength | The distance over which the wave's shape repeats. It is measured by distance from one point in a wave to an identical point later in the wave. |
Amplitude | A measurement of how far particles in the medium move away from their normal, or rest position. It could be described as the "height" of the wave. |
Wave period | Sometimes just called "period." The time required for once wave cycle to be completed. It is measured by finding the time it takes for one full patterns of a wave to pass a given point. |
Frequency | The number of cycles that occur in an amount of time, most commonly one second. Frequency is the inverse of period. |
Hertz | The unit of measurement used to measure frequency. One hertz is equal to one cycle per second. |
Wavefront | The collection of points that are reached at the same instant by a wave propagating through a medium. |
Wave Speed | The speed at which a wave travels. This depends on the medium the wave is travelling through. |
Radiation | The transfer of energy by electromagnetic waves. |
Electromagnetic Spectrum | The total range of frequencies or wavelengths an EM wave can have. It includes radio waves, microwaves, infrared light, visible light, ultraviolet light, x-rays, and gamma rays. |
Infrared | Also called IR light. It is close to the visible light spectrum and has slightly longer wavelengths than red light. The amount of IR light an object gives off depends on its temperature. |
Ultraviolet | Also called UV light. It is close to the visible light spectrum and has slightly shorter wavelengths than violet light. Some animals, like bees, can see in UV light. |
Transparent | Matter that transmits light. |
Translucent | Matter that scatters light when it transmits it. |
Opaque | Matter that reflects or absorbs, but does not transmit light. |
Absorption | The transfer of light energy into matter. |
Reflection | Light bouncing off a surface. |
Refraction | The change in direction of a wave as it passes from one medium to another at an angle. |
Scattering | Light is sent in many directions as it passes through a medium. |