15+Waves+and+Sound

 Waves and Sound

media type="custom" key="785795" = = = = =__Sound__= Sound is a vibration that exists whether it is heard or not. This vibration is a "wiggle" in time, and a wave is a "wiggle" in both space and time. Sound is longitudinal, meaning that it vibrates parallel to the direction of the wave, forming compressions and rarefactions, or areas of higher pressure and lower pressure. It travels through a medium, moving faster through denser material than through more sparse material, and is therefore unable to pass through a vacuum. Sound is reproduced by the longitudinal vibrations of atoms in the air. = = =__Electromagnetic Waves__= Electromagnetic waves are transverse, comprised of crests and troughs, and vibrate perpendicular to the wave direction. They are created by photons, and thus can move through a vacuum. There are various different types of electromagnetic waves, as identified by the electromagnetic spectrum. They are composed of two waves vibrating perpendicular to one another but moving in the same direction. One wave is electrical, the other magnetic, and their fields build upon and strengthen one another.

 Model of a sine wave:

=__Properties of Waves__= Amplitude: Distance from the midpoint of the wave to the crest or trough. Measured in decibels. Wavelength: Distance between any two identical points of a wave. Its symbol is the greek letter Gamma. Frequency: Rate at which vibrations occur. Measured in Hertz (cycles per second). Period: The amount of time taken for one cycle to occur. Wave Speed: Rate at which the wave travels. (Wavelength times frequency)



Equation For Waves

Wave Speed = Frequency x Wavelength

 Example

If a wave has a frequency of 256 cycles per second and a wavelength of 1.34 meters, how fast is it traveling?

Wave Speed = x Frequency =500.0 Hz Wavelength = 1.34 m

x = 256 * 1.34 x = 343.04 Answer - Wave speed is equal to 343 meters/second