What is the Speed of Sound in Vacuum?

Are you wondering about what could be the speed of sound waves in a vacuum? To understand this, we must know what sound is, the nature of sound waves, what factors measure their speed, what kind of medium the vacuum is, and in what mediums the waves can travel or not. But first, one must know what a wave is because knowing about all these factors can lead you to answer your question. So a wave is a transmitting dynamic disturbance that occurred due to a change from equilibrium in one or more quantities. They can be periodic or standing waves. At the same time, a vacuum is a space devoid of matter. The word vacuum is derived from the Latin adjective “vacuus ” for “vacant” or “void.” A vacuum is a region that has a gaseous pressure that is much less than the atmospheric pressure.

Types of Waves:

There are two types of waves most commonly studied in classical physics. Another third type of gravitational wave also exists. The main two types of waves are mechanical and electromagnetic waves.

1. A mechanical wave occurs due to an oscillation of matter and results in energy transfer through that medium—for example, sound waves.
2. Non-mechanical or electromagnetic waves do not require a medium for their propagation or the transfer of their energy to occur. Therefore, electromagnetic waves are the only type of non-mechanical waves in nature. They can pass through the vacuum of space quite well. According to their frequencies, electromagnetic waves have more specific designations. Examples include radio waves, infrared radiations, visible light, UV radiation, X-rays, and gamma rays.

Defining the Sound and its Speed:

Sound can be defined as a disturbance propagated by the collisions between the particles, initiating a chain of collisions where one molecule hits the next and so forth. The speed of sound can be defined as the distance through which a sound wave’s point journeys per unit of time. In a given medium under the same physical conditions, the speed of sound remains the same for all frequencies.

Formula:

The following formula explanation can explain the above theory. As we all know that the speed of sound is the distance traveled by the sound wave in a given period, the speed of sound can be determined by the following formula:

v = λ f

Where:

• v is the velocity
• λ is the wavelength of the sound wave is the distance between adjacent compressions or rarefactions
• f is the frequency is the number of waves that pass a point per unit of time.

Factors that Influence the Speed of Sound:

Since sound waves are medium-dependent, two factors influence the speed of sound in a medium. These factors are the density and temperature of the medium.

1.      Density: In a dense medium, the molecules are closely packed, resulting in a fast trip of sound; This implies that the speed of sound increases with the increase in the density of the medium.

2.      Temperature: The speed of sound is directly proportional to the temperature means it increases with the temperature rise.

Speed of Sound in Different Media:

The speed of the sound depends on the type and nature of the medium through which it travels. So let’s see how different mediums influence the velocity of sound waves.

In Solids: Solids are denser than liquids and gases because the molecules are closer to each other. This closeness means they can collide very quickly. Due to this fact, the sound wave travels faster in solids. On average, the speed of sound in solid is 6000 meters per second, in steel is 5100 meters per second, and sound travels 35 times faster in diamonds.

In Liquids: Just as solids are denser than liquids, similarly, liquids are denser than gases. This is because the molecules are more closely arranged in liquids than in gases. So the sound wave in liquids travels at speed between the speed of sound in solids and gases.

In Water: The speed of sound in water,1480 meters per second, is more than that of the air, and it travels faster in water than in air. The sound wave’s speed, in distilled water, may vary between 1450 to 1498 m/sec. In contrast, seawater’s speed is 1531 meters per second when the temperature is between 20oC to 25oC.

In Gas: Remember that sound velocity is independent of the density when it passes through a liquid or solid medium. The density is relatively uniform in gases irrespective of gas type because gases expand to fill the given space. The square root of the absolute temperature measured in Kelvin is proportional to the speed of sound. But this doesn’t make it dependent on the frequency of sound waves or pressure and density of the medium. None of the gases are ideal in real life, which causes a slight change in their properties. The speed of sound in air at 20 degrees Celsius is 343.2 m/s, translating to 1,236 km/h.

Speed of Sound in Vacuum:

The sound waves travel in a medium where there are particles needed for the propagation of these sound waves. However, since the vacuum is a space and is devoid of any particles, this results in no propagation of sound waves through the vacuum; This is why the speed of sound in vacuum is recorded at zero m/sec, as there are no particles present in the vacuum.

Bottom line:

So we discussed waves, vacuum, different types of mediums, and their influence on the speed of sound. The sound travels faster in liquids compared to gases and briskly in solids than in liquids. The sound travels faster in a medium that has a low density and high elasticity. Now that you know the reason behind the zero speed of sound waves inside a vacuum, I am sure this article will help you in your next physics assignment on sound waves.