Speed of Sound in Phases of Matter
Name: Tanisha M.
Does sound travel better threw liquids, gases or solids?
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
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.
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.
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.
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Update: June 2012