Speedofsound is how quickly a sound wave is able to propagate through space. It depends on the medium in which this wave propagates, but also on other factors related to it, such as temperature and pressure.
At sound waves they can undergo refraction when passing through media of different elasticities, thus suffering changes in velocity. In solid media, for example, sound propagates much faster than in gaseous or liquid media.
See too: Intensity, timbre and height - the qualities that differentiate the sounds
How is the speed of sound calculated?
The speed of sound can be calculated from your lengthinwave and frequency, as with any type of wave, regardless of its classification.
The formula used for calculate thevelocityinpropagation of the sound wave is as follows:
v – propagation speed (m/s)
λ – wavelength (m)
f – frequency (Hz)
However, the speed of sound can be determined from other factors such as air temperature. For that, it is possible to make a calculation in which this speed is calculated from the following formula:
To use this formula, which relates the speed of sound propagation to the air temperature, it is necessary to make the division between the ambient temperatures and the temperature of 0 °C, both measured in kelvin. Then it is necessary to extract the frogiz squareThe of the result obtained and multiply it by the factor 331.45. By doing this, it is possible to estimate with good precision the speed of sound at sea level, for different temperatures.
Let's do an example in which we want to estimate the speed of sound propagation at sea level at a temperature of 25 ºC (approximately 298.15 K). Watch:
The following table lists the speed of sound propagation with some air temperatures, all measured at sea level. Watch:
Temperature (°C) |
Sound speed (m/s) |
-10 |
330 |
0 |
332 |
10 |
337 |
20 |
343 |
30 |
350 |
100 |
390 |
The speed of sound propagation also varies according to the height at which the sound propagates in relation to sea level. At that time and at a temperature of 25 °C, the sound waves propagate with a speed of approximately 337 m/s or 1216 km/h. However, when we increase our altitude relative to that level, the density of the air decreases, causing the sound to travel at relatively slower speeds.
See too: Doppler Effect - the phenomenon that explains the change in sound frequency when we are in motion
Sound characteristics
Sound characteristics are the qualities that allow us to identify different sounds. The sound has three characteristics: intensity,height and letterhead.
- Sound intensity: refers to the “volume” of the sound.
- Height: is linked to the frequency of the sound.
- Timbre: relates to the shape of the sound waves, as well as how the source of the sound waves vibrates.
Want to know more about the subject? Access our text about the sound characteristics.
Speed of sound in different media
As we said, the speed of sound varies a lot according to the medium in which it propagates. When moving from one medium to another, the sound maintains its frequencyunchanged, however yours wavelength changes, as well as its propagation speed. Check out a table that lists the speed of sound in different media.
Quite |
Sound speed (m/s) |
Aluminum |
6420 |
Iron |
5960 |
Pure water |
1498 |
Sea water |
1531 |
Oxygen |
316 |
Analyzing the previous table, it is possible to see the direct dependence between thevelocityofsound the and the density the medium in which the sound propagates. Note the difference between the speeds of sound propagation in pure water and sea water, which has a large amount of diluted salts in it, and is therefore denser than distilled water.
The density of the medium in which sound travels directly affects its propagation speed. This is due to the proximity between neighboring molecules, which is more common in denser physical media, such as solids in general. In these media, the vibrations produced by sound waves are transmitted more quickly.
Another determining factor for the speed of sound is the elasticity the middle one. This feature concerns the ability to transmit vibration through collisions between molecules without significant energy losses.
Read too: 5 things you need to know about sound waves
Sound barrier
Sound barrier is the term used in reference to shock wave produced by a piece of furniture that moves faster than its own sound. The moment a body reaches the speed of sound, the sound waves produced by it move along with the body, so a large pressure zone is formed in front of the furniture.
the sound barrier is visible, since water droplets that are scattered in the air condense, due to the great pressure around you. In addition, the sound barrier can provide a great resistance for the mobile, so if it doesn't overtake it quickly, it won't be able to reach supersonic speeds.
By Rafael Hellerbrock
Physics teacher
Source: Brazil School - https://brasilescola.uol.com.br/fisica/a-velocidade-som.htm
