Why sound need medium to travel & light goes as its own?

Answer 1

Because sound is the vibration of molecules (typically air), therefore it needs molecules. Whereas light is an electromagnetic wave and doesn't need or operate based on molecules.

Answer 2

Sound is just a compression wave that travels through matter (it can be transmitted through air, water or solids). If there's no matter, there's nothing to transmit it -- that's why there's no sound in space. Light is made up of "particles" called photons which can travel through a vacuum, so it doesn't need matter to transmit it. But light does also have wave-like properties...

Answer 3

Sounds is an effect of waves in the medium that we detect with our ears and decipher with our brains. Light is neither a wave nor a particle so its physics are somewhat unique.

Answer 4

Sound and light waves are different. Sound waves are compression waves, like when you push a Slinky coil suddenly and the compression you make travels from one end of the coil to the other. Thus, compression waves move back and forth in the direction they are traveling. To compress, there has to be something to push...in the case of sound, it's the air or other medium that is compressed.

Your larnyx, for example, compresses (vibrates) the air in your throat when you talk. And, like the Slinky, that compressed air (vibration) compresses air next to it, which compresses air next to it, which compresses air next to it, and on and on...creating the vibrating compression waves traveling out the throat and into the surrounding air so your friends can hear what you have to say. On a normal day, the compression sound waves of your voice and sound in general travel about 500-600 mph through the air.

On the other hand light waves travel at about 186,000 mps (that's miles per second) in a vacuum. Way faster than sound. Which is why we hear lightening thunder way after we see the bolt in the sky. Unlike the compression waves of sound, light waves are transverse waves. Which means they wiggle up and down, like snapping a rope from one end and watching it wiggle all the way to the other end.

But, contrary to what you've heard from other answers, light waves do need a medium to travel in as well. The medium is made up of the countless bundles of light called photons. That's right, light is its own medium, which is why some of the answerers say light can travel in a vacuum. It does, but only because light quanta, the photons, fill that vacuum and provide the medium to support its wave action.

I like to use ripples on a pond to explain the so-called dual nature of light. The surface water of the pond is made of countless water molecules. They are like the countless photons of light.

When energy is applied to the surface of the pond, by throwing a stone into the pond for example, ripples are created in the water. But those ripples are just groups of water molecules moving up and down (transverse) along the surface. In other words, the water molecules make up their own medium for the ripples (transverse waves) to travel in.

When light is produced, that's like throwing the stone into the pond. Light waves of photons are produced and carry the photons outward from the source of that light (like the Sun or your flashlight). Thus, light creates its own medium...the photons; so it doesn't need something else to travel in.

In fact, light travels better in a vacuum than in other media because there is nothing out there for the photons to run into. That's why we say the velocity of light is c = 186,000 mps "in a vacuum". In the other media it is likely to travel slower than 186,000 mps.

Answer 5

Sound is the compression of air or solids in a recurring cycle. Light is an electromagnetic wave,
and needs no matter, in fact matter gets in it's way.

Answer 6

Sound is a compression wave. It needs something to compress, whether that be air molecules or water molecules, or something else. Light is electromagnetic radiation, and is it's own, self-contained entity.

Answer 7

sound is a type of longitudinal wave and light is a type of transerve wave.
by the property of waves,longitudinal waves require medium to travel,whereas transverse do not require.since sound is longitudinal it requires medium while light dosent.

Answer 8

Sound is a wave which is created by vibrating objects and propagated through a medium from one location to another.

A wave can be described as a disturbance that travels through a medium, transporting energy from one location to another location. The medium is simply the material through which the disturbance is moving; it can be thought of as a series of interacting particles. The example of a slinky wave is often used to illustrate the nature of a wave. A disturbance is typically created within the slinky by the back and forth movement of the first coil of the slinky. The first coil becomes disturbed and begins to push or pull on the second coil; this push or pull on the second coil will displace the second coil from its equilibrium position. As the second coil becomes displaced, it begins to push or pull on the third coil; the push or pull on the third coil displaces it from its equilibrium position. As the third coil becomes displaced, it begins to push or pull on the fourth coil. This process continues in consecutive fashion, each individual particle acting to displace the adjacent particle; subsequently the disturbance travels through the slinky. As the disturbance moves from coil to coil, the energy which was originally introduced into the first coil is transported along the medium from one location to another.

A sound wave is similar in nature to a slinky wave for a variety of reasons. First, there is a medium which carries the disturbance from one location to another. Typically, this medium is air; though it could be any material such as water or steel. The medium is simply a series of interconnected and interacting particles. Second, there is an original source of the wave, some vibrating object capable of disturbing the first particle of the medium. The vibrating object which creates the disturbance could be the vocal chords of a person, the vibrating string and sound board of a guitar or violin, the vibrating tines of a tuning fork, or the vibrating diaphragm of a radio speaker. Third, the sound wave is transported from one location to another by means of the particle interaction. If the sound wave is moving through air, then as one air particle is displaced from its equilibrium position, it exerts a push or pull on its nearest neighbors, causing them to be displaced from their equilibrium position. This particle interaction continues throughout the entire medium, with each particle interacting and causing a disturbance of its nearest neighbors. Since a sound wave is a disturbance which is transported through a medium via the mechanism of particle interaction, a sound wave is characterized as a mechanical wave.

Electromagnetic waves (i.e. visible light) are waves which have an electric and magnetic nature and are capable of traveling through a vacuum. Electromagnetic waves do not require a medium in order to transport their energy. Mechanical waves are waves which require a medium in order to transport their energy from one location to another. Because mechanical waves rely on particle interaction in order to transport their energy, they cannot travel through regions of space which are devoid of particles. That is, mechanical waves cannot travel through a vacuum.

Dr. H