| A | B |
|---|
| Mechanical wave | A disturbance in matter that carries energy from one place to another. |
| Medium | The material through which a wave travels. |
| Crest | The highest point of the wave above the rest position. |
| Trough | The lowest point of a wave below the rest position. |
| Transervse wave | A wave that causes the medium to vibrate at right angles to the direction in which the wave travels. |
| Compression | An area where the particles in a medium are spaced close together. |
| Rarefaction | An area wher the particles in a medium are spread out. |
| Longitudinal Wave | A wave in which the vibration of the medium is parallel to the direction the wave travels. |
| Surface Wave | A wave that travels along a surface separating two media. |
| Periodic Motion | Any motion that repeats at regular time intervals. |
| Period | The time requires for one cycle, a complete motion that returns to its starting point. |
| Frequency | The number of complete cycles in a given time. |
| Hertz | Used to measure frequency. |
| Wavelength | The distance between a point on one wave and the same point on the next cycle of the wave. |
| Amplitude | The maximum displacement of the medium from its rest position. |
| Reflection | Occurs when a wave bounces off a surface that it cannot pass through. |
| Refraction | The bending of a wave as it enters a new medium at an angle. |
| Diffraction | The bending of a wave as it moves around an obstacle or passes through a narrow opening. |
| Interference | Occurs when two or more waves overlap and combine together. |
| Contructive Interference | Occurs when two or more waves combine to produce a wave with a larger displacement. |
| Destructive Interference | Occurs when two or more waves combine to produce a wave with a smaller displacement. |
| Standing wave | A wave that appears to stay in one place. |
| Node | A point on a standing wave that has no displacement from the rest position. |
| Antinode | A point where a crest or trough occurs midway between two nodes. |
| Sound waves | Longitudinal waves that travel through a medium. |
| Intensity | The rate at which a wave's energy flows through a given area. |
| Decibel | A unit that comapres the intensity of different sounds. |
| Loudness | A physical response to the intensity of sound, modified by physical factors. |
| Pitch | The frequency of a sound as you perceive it. |
| Sonar | A technique for determining the distance to an object under water. |
| Doppler Effect | A change in sound frequency caoused by the motion of the sound source, motion of the listener, or both. |
| Electromagnetic Waves | Transverse waves consisting of changing electric fields and changing magnetic fields. |
| Electric Field | Produced by electrically charged particles and by chaning magnetic fields. |
| Magnetic Field | Produces magnetic forces. |
| Electromagnetic Radiation | The transfer of energy by electromagnetic waves traveling through matter or across space. |
| Photoelectric Effect | The emission of electrons from a metal caused by light striking the metal. |
| Photons | Packets of electromagnetic energy. |
| Electromagnetic Spectrum | The full range of frequencies of electromagnetic radiation. |
| Transparent | Material that transmits light, which means it allows most the light that strikes it to pass through it. |
| Translucent | Material that scatters light. |
| Opaque | Material that either absorbs or reflects all of the light that strikes it. |
| Image | A copy of an object formed by reflected waves of light. |
| Regular Reflection | Occurs when parallel light waves strike a surface and reflect all in the same direction. |
| Diffuse Reflection | Occurs when parallel light waves strike a rough, uneven surface, and reflect in many different directions. |
| Mirage | A false or distorted image. |
| Polarized Light | Light with waves that vibrate in only one plane. |
| Scattering | Light is redirected as it passes through a medium. |
| Dispersion | The process in which white light separates into colors. |
| Primary Colors | Red, Green, and Blue |
| Secondary Colors | Cyan, yellow, and magenta |
| Complementary colors of light | Any two colors of light that combine to from white light. |
| Pigment | A material that absorbs some colors of light and reflects other colors. |
| Primary Pigments | Cyan, yellow, and magenta |
| Secondary Pigments | Red, Green and Blue |
| Complementary colors of pigments | Any two colors of pigments that combine to make black pigment. |
| Luminous | Objects that give off their own light. |
| Incandescent | Light produced when an object gets hot enough to glow. |
| Laser | A device that generates a beam of coherent light. |
