Label: Moon Spirits Records - MSRCD03 • Format: CD Compilation • Country: France • Genre: Electronic • Style: Psy-Trance
An echo is the sound you hear when you make a noise and the sound wave reflects off a distant object. Besides the novelty Sir Roland Hanna* - Swing Me No Waltzes hearing your words repeated, echoes can be used to estimate the distance of an object, its size, shape and velocity, as well as the velocity of sound itself.
This lesson will answer those questions. Useful tool: Units Conversion. Sound is a waveform made from vibrating matter. The sound wave travels through matter—especially air—in a straight line. When the wave hits a different material, some of it is reflected, absorbed and transmitted through the material. In the case of a sound wave in air hitting a solid wall, most of the sound is reflected. If the wall is relatively flat, perpendicular to the source of the sound, and far enough away but not too farthen you can hear the reflected waveform or echo.
If the sound comes back in about 0. Since sound travels at approximately feet per second or about meters per second and Physical - Sonicsurfers - Echoes the wall was 50 feet or 15 meters awaythe sound would return in 0. This can be seen from the relationship:. That is enough time to be able to distinguish between the noises you Physical - Sonicsurfers - Echoes and the reflected sound. Illustration of person and an echo You must have the Flash plug-in to see animation. Echoes can be used to tell how far away an object is, how fast the object is moving, and even its shape.
By knowing the speed of sound and measuring the time it takes to hear the echo, you can calculate the distance of the object. A sonar device sends out a sound and automatically calculates the distance of an object. Submarines use sonar to find objects under the water, including other submarines. The "ping" sound heard in a submarine comes from the sonar device sending out a sound wave under water.
Fishermen also use sonar to find schools of fish. Since this is an electronic device, the time it takes for the wave to return can be much less than the 0. For example, if the speed of sound in water is meters per second and the fisherman's sonar device detects an echo in 0.
Sonar and radar work on the same principle. Sonar uses sound waveswhile radar uses electromagnetic Physical - Sonicsurfers - Echoes . When a wave bounces off a moving object, the frequency of the sound changes, according to the relative velocity of the object. Velocity is the measurement of speed and direction. If the object is moving toward you, the frequency or pitch of the sound gets higher.
When it is moving away, the pitch gets lower. The faster the object is moving, the greater the change in frequency or pitch. This is called the Doppler Effect. You have probably experienced the Doppler Effect when you heard how the sound of an ambulance siren changes pitch as it passes by.
The Doppler Effect can be used to measure the velocity of an object by comparing the frequency of the sound sent out to the frequency of the sound reflected by in the echo. A sonar device is usually used to calculate the velocity of the object.
Note : Doppler radar works on Lover Man - Duke Ellington And His Orchestra - The Duke: Edward Kennedy Ellington similar principle to measure the speed of storms in weather prediction, except that it uses echoes from electromagnetic waves.
Bats use echoes to find good tasting moths, while flying around at night. The bat sends a sharp click or chirping sound and then hears and processes any echoes off other objects in the area. Bats have large ears that are very sensitive to sounds in certain wavelengths. Their brains are also able to process the sound of the echo coming off a flying moth to determine how far away it is, which direction and how fast it is flying, and the size of the moth.
It continues to send out sound and receive echoes until it zeroes in on the moth and has a good meal. When Physical - Sonicsurfers - Echoes reflects off a stepped grating, the echo can have interesting effects.
The most common is a "chirping" or "pinging" sound. Echoes from the great Mayan Churner - Filth Cleanser (File, Album) at Chichen Itza, Mexico sound like the quetzal bird that is found in the Mayan area. The shape of each riser on the pyramid's staircase measures over 10 inches, which is too steep for easy climbing but a perfect dimension to create the chirp.
The placement of rocks in the areas also affects the quality of the echoes. Clap in front of a painting of horses and the echo sounds like thundering hoof-beats. But if you clap in front of a painting Physical - Sonicsurfers - Echoes a cat, almost no echo returns.
If you walk by a picket fence that is near the sidewalk, you can hear the pinging echo of the noise you make. You can also sometimes hear this unusual effect near a flight of stairs. Echoes are the reflection of sound from relatively flat object that is far enough away that you can discern the time difference.
Echoes are used to measure distance, velocity, and the shape of objects. Echoes off gratings result in an unusual pinging sound. Top-rated books on Sound Waves. Do you have any questions, comments, or opinions on this subject?
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