We’ve always wondered about the speed of sound during the delay of thunder after lightning. Although slower than light, sound can reach far-off places within seconds and travel through different mediums.
We know that sound travels an approximate 340 meters per second at room temperature, but do you know that the speed varies, not only according to the traveling medium but also according to its temperature.
Be it solid, liquid, or gas, the sound waves travel at different speeds when the temperature varies, and the correlation is interesting.
Read on to find out more about why this is so, and let us see how the speed of sound is related to the temperature of the medium.
In this article, we’ll be discussing the characteristics of sound waves, how it propagates through a medium, and how the speed of sound can be varied according to the temperature of the traveling medium.
Does sound travel faster as temperature increases?
Yes. The speed of sound is dependent on the temperature. Through various physical experiments, it has been seen that as the temperature of the medium increases, the sound waves seem to travel faster.
We can calculate the speed of sound from the following equation.
v = (332+0.61 t);
V = speed of sound in the medium in meters/second
t = temperature of the medium in degrees celsius
From the relation, it is clear that the speed of sound increases with the temperature rise. Here 332 meters per second is the speed of sound at zero degrees celsius.
It can be seen that for every subsequent degree rise in temperature, the speed of sound increases by .61 meters per second. This linear relationship holds together for sound traveling through the air.
It is a generalization, and in real life, there can be variations according to other factors, including humidity, air pressure, etc.
How does temperature affect the speed of sound?
To explain this, we have to know how sound propagates through a medium. Sound is a mechanical wave in physical form, and sound travels through a medium by transferring the wave’s energy through the particles.
When a sound wave is propagated through the vibration of an object, it causes the nearby particles to vibrate along with it. This causes two regions near the object; compression and rarefaction.
Compressions are high-density areas when particles are crowded due to vibration, and every compression leaves an area of low density called rarefaction. The particles vibrate and thus transfer the energy to the adjacent particles to create sound waves.
Here, vibrations of the particle play an integral role in the propagation of sound. This is why sound can’t travel without a medium and why we can’t hear sound in outer space.
The particles vibrate, in general, due to high energy. So, when the temperature increases, energy is supplied to the particles in the form of heat and makes them more active. This makes it easier for the sound to propagate, and this is how temperature affects the speed of sound.
Why does the speed of sound depend on air temperature?
We have already seen in the equation that the speed of sound depends on air temperature. Now, let us go into its depth and know why it is so.
The vibrations of the particles that cause the movement in the subsequent particles are due to the transfer of energy from one to another. It takes energy to excite a particle and to cause it to move.
However, when the temperature increases, there is an inherent energy in all the particles that aid them in moving. Thus, sound energy can travel a lot faster as the particles are already vibrating.
A sound travels at about 332 meters/second at zero degrees celsius. But, as the temperature increases, extra energy is imparted to the particles in the form of heat energy, and thus the particles begin to vibrate. It is calculated that there is an increase of .61 meters per second in speed for every degree rise in temperature.
What is the difference in the speed of sound on a warm day versus on a cold day?
Now, coming to practical applications of the correlation mentioned above, the speed of sound in air is more on a warm day than on a cold day.
This is very simple to understand as the average temperature of air will be more than its temperature on a cold day. The higher temperature provides more energy to the particles in the air, and the hot air is more welcoming and provides an easier path for the sound waves to travel.
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Final Thoughts
In this article, we have seen that the speed of sound changes as the temperature rises. Sound is a mechanical wave in nature and causes the particles near the vibrating body (the sound source) to vibrate. However, the speed of sound is dependent on many factors. Sound, a longitudinal wave, causes a variation in particle density and compressions and rarefactions in the following region.
The speed of sound on a warm day is more than that of a cold day, provided that other variables don’t change. We have seen an in-depth analysis of why and how the speed of sound increases as the temperature increases. Sound travels by transferring energy from one particle to another until it attenuates completely.
Thus, particles need to be excited and vibrate for the subsequent particles to start moving, creating a wave of energy transfer. On a warm day, the temperature and inherent temperature are more than that on a cold day, providing the particles in the atmosphere with much more energy. The particles vibrate, and this paves an easy wave for the sound wave than that of a relatively colder day.