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Name: Tanisha M.
Status: student
Age: 11
Location: N/A
Country: N/A
Date: 2/26/2003


Question:
Does sound travel better threw liquids, gases or solids?


Replies:
Tanisha,

In general, sound travels fastest through solids, slightly less fast through liquids, and slower through gases.

This is because the particles (atoms or molecules) in a solid are touching each other and rather fixed together. That is why a solid is "solid." Since the particles are bonded together, a sound wave moving one, immediately transfers the motion the one touching it. A sound wave hitting one, is almost immediately transferred to a neighbor.

In a liquid, the particles are touching each other, but they are not fastened to each other quite so strongly as they are in a solid. Some of sound's energy is wasted pushing the particles around because they can slide past each other. Some of sound's energy is wasted that way and that is why it moves slower.

In a gas, the molecules are rather far apart. For sound to travel through a gas, the molecules must move quite a distance before they collide with other molecules. Sound energy cannot move as quickly when the molecules are not in contact with each other.

Regards,
ProfHoff 574


You have to define the term "better". It can mean the SPEED of sound, or it can mean how much the loudness of the sound decreases as it moves through a substance. This is called ATTENUATION.

As a rule of thumb, sound travels FASTER in the order: "solids" faster than "liquids" faster than "gases".

Having said that there is a lot of exceptions because the speed depends upon whether the wave motion is in the direction of the sound wave is moving or perpendicular to the direction of the sound wave. In addition, it depends upon the temperature, the frequency of the sound (not all sound pitches travel at the same speed), the structure if you are considering solids. The area of study of how sound travels is really very complicated beyond the rough order above.

Vince Calder


Dear Tanisha,

Sounds travel fastest in solids. Think about what you know about molecules in solids liquids and gasses. Molecules are farthest apart when in a gaseous state. They are zinging around having a great old time. Think of a box of marbles being dumped on the floor and rolling everywhere. Next come the liquids with their molecules, vibrating and much closer together. Same marbles in a big box with a little less room to roll around. In solids, the molecules are much closer together. Think of all your marbles packed into a peanut butter jar, full to the top, not too much room to move.

Now about sound... Sound is a wave that needs something to travel in. Think the crowded lunch line in the cafeteria. Someone pushes and then that person bumps the person in front of them, then the person in front of them and so on. Sound travels fastest in solids because the molecules are closet together and can bump one another easier. It travels next best in liquids, and the slowest of all in gasses. I hope that answers your question.

Good question, share it with your science class.
Happy science!

Martha Croll



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