Why does sound travel so fast in solids and liquids?

Sound can travel in air, solids, and liquids. The vibrations of the object propagate through the medium and eventually reach the human ear, causing the eardrum to vibrate, and then to the auditory nerve, and the person hears the sound. So, we can hear sound mainly because our ears are receiving vibrations from objects.

So, which is faster when sound travels in air, in water, or in solids? Scientists have determined that sound travels much faster in both solids and liquids than in gases, with a speed of 332 meters per second in air, 1,450 meters in water, 1,500 meters in seawater, 5,050 meters in steel, and more than 8 kilometers per second in mantle rocks. The speed of sound propagation is closely related to the properties of the medium, which is directly proportional to the modulus of elasticity of the medium and inversely proportional to the density of the medium.

Different medium molecules have different resistance skills, that is, different elastic moduli, and the medium with a large resistance ability has a large ability to transmit vibration, and its influence on sound far exceeds the influence of density, and the speed of sound transmission is fast.

If the source of the wave producing the sound does not change, the frequency of the wave does not change, so the propagation speed of the sound is related to the medium. Sound travels at different speeds in different mediums. There are two reasons why sound travels fastest in solids:

1) The size of the counter-equilibrium force of the search medium determines the propagation speed of the sound, and it is proportional, the greater the counter-equilibrium force, the faster the propagation speed of the sound; The opposite is true. So what is the countervailing equilibrium of the medium? We all know that all matter is made up of molecules or atoms.

When a molecule or atom of a substance does not want to be in equilibrium and deviates from the equilibrium position, then the molecules or atoms around it will not allow it to deviate, and then squeeze it together to return to the equilibrium position. Liquids are more resistant to equilibrium than air, while solids are more resistant to equilibrium than liquids. Therefore, we say that sound travels the slowest in the air and the fastest in solids.

2) The speed of sound propagation is also closely related to the density of the medium and is directly proportional. The denser the medium, the faster the sound travels, and vice versa. So what kind of medium is dense?

The tighter the atoms or molecules that make up a substance, the denser and tougher it becomes. Therefore, in solids, liquids, and air, the density should be arranged in such a way as follows: solid, liquid, and air.

As a result, sound travels the slowest in air and the fastest in solids. The essence of sound propagation is the conduction of vibration, and the conduction of vibration requires molecules (which is why vacuum cannot transmit sound) The molecular density of solids is much denser than that of liquid gases, and the transmission of vibration is naturally faster than that of sound transmission.

Solids and liquids are much denser than gases, and from this point of view, sound should travel less in these media than in air. However, the elastic modulus of solids and liquids is generally much greater than that of gas, in other words, in the process of sound propagation, the medium molecules vibrate in turn near their equilibrium position, and when a molecule deviates from the equilibrium position, the surrounding other molecules have to pull it back to their position, that is, the medium molecule has a ability to resist the deviation from position. The modulus of elasticity of solids and liquids is greater than that of gases, so sound travels faster in solids and liquids than in air.

However, because some solid substances have a very small modulus of elasticity, such as lead, which cannot return to its original shape like steel after being struck by an external force, the sound velocity in lead is only 1200 meters per second. Rubber is porous and has a special chemical structure, so the sound velocity in rubber is smaller, only 62 meters per second.

The speed at which sound travels from a solid must be greater than that of a liquid. This statement is false.

For example, the propagation velocity of sound in cork is about 500 m s, which is less than the propagation velocity of sound in liquids (e.g., 25 °C, the propagation speed of sound in seawater is 1531 m s).

But in most cases, V solids V liquid V gas

Sound travels fastest in solids, and the speed of sound varies by the magnitude of the solid, liquid, and gas.

In physics, sound is generated by the vibration of an object, and the object that is emitting sound is called the sound source. The number of times an object vibrates in a second is called frequency, and the unit is hertz, the letter Hz. The human ear can hear the sound of 20 20000 Hz, and the most sensitive is the sound between 200 and 800 Hz.

The propagation speed of sound in different media is generally solid, liquid and gas (exceptions, such as: cork 500m s, less than kerosene (25), distilled water (25), etc.), and the propagation speed of sound is related to the type of medium and the temperature of the medium.

The speed at which sound propagates in different media is different, and the speed of sound varies according to the magnitude of solid, liquid, and gas.

For example, we have watched the TV series "Railway Guerrillas", in which the guerrillas lie on the tracks and listen to the sound of the train running in the tracks, they can arrive before the airborne sounds, so as to prepare for the attack.

Solids are the fastest, followed by liquids, and finally gases, and then expanding, vacuum cannot transmit sound, and the medium of sound is propagated in all directions in the form of sound waves.

Please give examples (in life) as soon as possible. The essence of sound is a compressed wave of matter, the speed of sound 2; =dp The greater the speed of sound, the greater the speed at which sound travels, and it can also be thought of like this, sound is like a bullet that penetrates density.

Solid. For the same wave, the frequency is the same in different media, and the speed of the wavelength is fast, and the wavelength mainly depends on the medium, and the wavelength is the longest in solids.

The answer is definitely solid, for example, ancient people liked to listen to the footsteps of the enemy when they were fighting, and they also listened to the sound of trains on the railroad tracks, and people often said that the partition wall has ears, which is also the truth.

Air (25 degrees) 340 m/s Distilled water (25 degrees) 1497 m/s Steel, Iron 5200 meters per second.

Solid, people detect distant trains coming and not leaning on the tracks to listen.

Sound propagation is not like light, it requires a medium, and the denser the medium, the faster it travels, because the density of solids is the highest, so sound travels faster in solids than in liquids.

As long as the frequency of the wave source does not change, the frequency of the wave does not change. The speed of the wave is determined by the medium, for example, the speed of sound propagation in air is not the same as that in water, and the speed of sound propagation in air is the slowest compared to other common media (such as solid liquids).

According to v = f (v is the wave speed, wavelength, f is the frequency), it is concluded that whether the wavelength of the wave changes, as long as the medium through which the wave passes is uniform, the inhomogeneous wavelength changes, and the uniform wavelength does not change.

So in the air, it depends on the medium.

A medium is required for sound propagation, and the denser the medium, the faster it travels, because solids have the highest density, so sound travels faster in solids than in liquids.

The propagation of sound in a medium depends on the collision of particles in the medium, and the faster the speed is when the direction of the collision is more likely to coincide with the direction of sound wave propagation.

In gaseous liquid solids, these particles are usually molecules or atoms (collectively referred to as molecules for convenience). The most basic difference between the three states of matter of gas, liquid, and solid is the average free path of the molecules, or the degree of binding, or the average spacing. The free path of the irregular movement of the molecules in the gas is large, that is, the distance they run before the next collision is long, that is, the waiting time for the next collision is long, so the propagation of mechanical waves naturally takes longer.

The average free path of liquids is much smaller, the molecules are only fixed in a small area to vibrate, and the time required for the next collision is shorter, so the mechanical wave travels faster. Solids have a smaller average free path than liquids, so they propagate faster.

So from a macroscopic point of view, in general, in terms of density, solid, liquid, and gas, so this situation will occur. However, it is not absolute, so it is not entirely correct to distinguish the speed of sound by density, such as water and ice. But ice is known to be less dense than water.

After experiments, we already know that temperature also contributes greatly to the propagation of the speed of sound, and generally the temperature of the same medium increases with the speed of sound, of course, this can be explained by the increase in temperature and the acceleration of molecular vibration. In addition, there is the problem of materials, shape, doping, etc., which can change the speed of sound propagation.

Therefore, the speed of sound propagation has a lot to do with the interaction between the molecules in the medium, if the interaction of the molecules in the medium is very strong, then the speed of propagation is relatively fast, on the contrary, if it is weaker, even if the density is relatively large, the speed of sound propagation will not be very high. (e.g. iron and lead).