Speed of Sound, What is it and How High is it?

Speed of Sound What is it
Speed of Sound What is it

We dive right into the field of physics to talk about the speed of sound as a concept and why it is current at the moment.

Speed of sound is the speed at which sound waves travel through different media. It varies depending on the medium in which the waves are transmitted and in the atmosphere this speed reaches 343.2 meters per second.

The important thing of all, that is clear as the first great lesson to learn about the speed of sound, is that it does not depend on the wave itself, but on the characteristics of the medium through which it passes.


In this way, science has been able to measure the speed of sound in different media, these being the main figures:

  • In air , at a temperature of 20 degrees Celsius, the speed of sound has been found to reach 343.2 meters per second.
  • If the temperature in the air is 0 degrees Celsius, the speed of sound reaches 331 m / s.
  • In the water, at 25 degrees, the speed reaches 1,593 m / s.
  • In other elements, the speed of sound grows as a function of each one: in steel it reaches 6,100 m / s; in aluminum, 6,400 m / s; and in cadmium it reaches 12,400 m / s.

With these data, one thing is clear: that the speed of sound is much higher if sound waves propagate on solid bodies than on liquids or gases. A very graphic example to understand this question: if we stand on the rails of a train, we will hear the arrival of it much earlier than if we are in the air. Why? Because the waves travel much faster through the materials of the rails.


The concept of the speed of sound is very fashionable today, as scientists from the University of Cambridge and Queen Mary University of London have discovered the maximum speed at which sound can travel: no less than 36 kilometers per second.

This finding maintains that these 36,000 m / s are 100 times faster than the speed of sound in air and three times faster than the propagation of waves in the diamond, where they reach 12 kilometers per second.


The key question to ask at this point is: what medium allows sound to travel at such a high speed? The answer, according to the new study from these universities, is found in solid atomic hydrogen. This form of the element only occurs under immense pressure, such as that found in the cores of gas giant planets like Jupiter. Under those conditions, hydrogen is compressed into a metallic solid that can easily conduct electricity and also sound.

‘We believe that the results of this study could have further scientific applications in helping us find and understand the limits of different properties such as viscosity and thermal conductivity relevant to high-temperature superconductivity, quartz-gluon plasma, and even the physics of black holes, “says the lead author of the research.


The researchers hit the 36-kilometer-per-second record by studying two fundamental constants – the fine-structure constant and the proton-electron mass ratio. These data play an important role in scientific study, including in this case, the properties of materials.

One prediction made by theory is that the speed of sound should decrease with the mass of the atom, so by extension sound should travel faster in solid atomic hydrogen. The team used quantum mechanical calculations to test how fast it would move through the material, and found that the velocity is close to the theoretical fundamental limit.

Although it is a new scientific discovery, its impact would not affect people’s daily lives, although understanding this phenomenon could improve the understanding of various models for a series of specialties.


Where people can notice the effects of science in relation to the speed of sound is in the train project that the Virgin company is preparing. Hyperloop has already done its trials transporting people in its hyperdrive capsule.

The project responds to the work of several years that could represent a whole paradigm shift in the transport of people. The pilot that the company has made with two passengers has been produced in a vehicle built specifically for two people, although the idea that Virgin is designing prototypes for 28 passengers. It was about keeping an eye on everything related to people’s safety and everything went perfectly.

The arrival of Hyperloop, the supersonic train that promises to transport people at a speed of 1,200 kilometers per hour, is getting closer and closer.

Although there is still time for all this to become a reality, the speed of sound has once again been challenged and everything looks like we will touch it in the future.

“For the past several years, the Virgin Hyperloop team has been working on turning their innovative technology into reality,” said Sir Richard Branson, founder of the Virgin Group. “With today’s successful test, we have shown that this spirit of innovation will indeed change the way people around the world live, work and travel for years to come.”

Although it is a very expensive transport for all the technology it brings with it, in addition to the infrastructure itself, the arrival of the Hyperloop would have an impact on sectors such as rail and transport in general. Can you imagine what taxis would be like in the future or in what way all the deliveries of products that we buy on the Internet would be carried out?