When a wave meets the surface between two different materials or conditions (e.g., air to water), part of the wave is reflected at that surface and another part continues on, but at a different speed. When a wave passes an object that is small compared with its wavelength, the wave is not much affected for this reason, some things are too small to see with visible light, which is a wave phenomenon with a limited range of wavelengths corresponding to each color. This phenomenon (e.g., waves in a stretched string, vibrating air in a pipe) is used in the design of all musical instruments and in the production of sound by the human voice. Structures have particular frequencies at which they resonate when some time-varying force acting on them transfers energy to them. Resonance is a phenomenon in which waves add up in phase (i.e., matched peaks and valleys), thus growing in amplitude. The human ear and brain working together are very good at detecting and decoding patterns of information in sound (e.g., speech and music) and distinguishing them from random noise. Sound is a pressure wave in air or any other material medium.
UNDISTURBED POSITION OF A WAVE SERIES
Information can be digitized (converted into a numerical representation), sent over long distances as a series of wave pulses, and reliably stored in computer memory. Waves, which transfer energy and any encoded information without the bulk motion of matter, can travel unchanged over long distances, pass through other waves undisturbed, and be detected and decoded far from where they were produced. Waves can be combined with other waves of the same type to produce complex information-containing patterns that can be decoded at the receiving end. The wavelength and frequency of a wave are related to one another by the speed of travel of the wave, which, for each type of wave, depends on the medium in which the wave is traveling.
A simple wave has a repeating pattern of specific wavelength, frequency, and amplitude. Whether a wave in water, a sound wave, or a light wave, all waves have some features in common. This phenomenon (e.g., waves in a stretched string, vibrating air in a pipe) is used in speech and in the design of all musical instruments.įrom A Framework for K-12 Science Education: Practices, Crosscutting Concepts, and Core Ideas (pages 131-132) Structures have particular frequencies at which they resonate. Resonance is a phenomenon in which waves add up in phase in a structure, growing in amplitude due to energy input near the natural vibration frequency. Information can be digitized (e.g., a picture stored as the values of an array of pixels) in this form, it can be stored reliably in computer memory and sent over long distances as a series of wave pulses. The reflection, refraction, and transmission of waves at an interface between two media can be modeled on the basis of these properties.Ĭombining waves of different frequencies can make a wide variety of patterns and thereby encode and transmit information. Geologists use seismic waves and their reflection at interfaces between layers to probe structures deep in the planet.īy the end of grade 12. The wavelength and frequency of a wave are related to one another by the speed of travel of the wave, which depends on the type of wave and the medium through which it is passing. A sound wave needs a medium through which it is transmitted. (Boundary: The discussion at this grade level is qualitative only it can be based on the fact that two different sounds can pass a location in different directions without getting mixed up.)Įarthquakes cause seismic waves, which are waves of motion in Earth’s crust.īy the end of grade 8. A simple wave has a repeating pattern with a specific wavelength, frequency, and amplitude. Waves can add or cancel one another as they cross, depending on their relative phase (i.e., relative position of peaks and troughs of the waves), but they emerge unaffected by each other. Sound can make matter vibrate, and vibrating matter can make sound.īy the end of grade 5. Waves of the same type can differ in amplitude (height of the wave) and wavelength (spacing between wave peaks). When waves move across the surface of deep water, the water goes up and down in place it does not move in the direction of the wave-observe, for example, a bobbing cork or seabird-except when the water meets the beach. From A Framework for K-12 Science Education: Practices, Crosscutting Concepts, and Core Ideas (pages 132-133)īy the end of grade 2. Waves, which are regular patterns of motion, can be made in water by disturbing the surface.
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