Why sound travels faster in solids

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Question Why does sound travel faster in solids than in liquids, and faster in liquids than in gases air? Asked by: Will K Answer Sound is nothing more than a local disturbance whose propagation is facilitated by the collisions between particles; this disturbance propagates in a logitudnal wave; imagine one molecule hitting the next molecule, and then that molecule hitting the next, and so forth.

The distances between molecules in solids are very small, i. Because they are so close, than can collide very quickly, i. Solids are packed together tighter than liquids and gases, hence sound travels fastest in solids. The distances in liquids are shorter than in gases, but longer than in solids. Sound waves travel faster and more effectively in liquids than in air and travel even more effectively in solids.

This concept is particularly hard to believe since our general experiences lead us to hear reduced or garbled sounds in water or behind a solid door. There are reasons for this. Most of our everyday experiences are when a sound travels first through air and then through water or a solid. When the sound wave transfers from air into a solid some of it is reflected back into the air and some may be absorbed by the new medium. The noise coming from a room will be reduced if an observer outside closes the door.

Sound from within the room will travel to the closed door and start it vibrating. The vibrating door will set the air on the outside vibrating too and a little of the original sound will be transmitted to the observer. However, some of the sound arriving at the door will have been reflected back into the room actually making the noise inside the room louder!

Also some of the sound energy will have been used up in making the door begin to vibrate so we can say some of the sound has been absorbed by the door. Hearing sounds through solids. If the sound is made directly within the solid and this travels directly to the ear then both reflection and absorption are reduced or eliminated.

Thus putting an ear to a desk and making a quiet sound at the other end will demonstrate how well the sound will travel.