What is Sound? | Best Physics Review



Sound is a pressure disturbance that moves through a medium in the form of mechanical waves. These mechanical waves transfer energy from one particle to the next. Notice here that sound needs a medium to travel through.

That can be something like air, water, or some other matter. Either way, sound has to have a medium to travel through. The reason it needs to travel through something is because it’s transferring energy from one particle to the next.

Another thing you need to know about sound is that sound is transferred through vibrations. Vibrations transfer energy to adjacent particles. This may be a little bit contrary to what you thought about sound, because you may think that sound is the actual movement of particles over a great distance.

Actually, the particles aren’t moving. Said vibrations transfer energy from one particle to an adjacent particle. That way, sound moves out through the waves into other areas. Actual matter is not moving with the sound. The sound is just moving from one particle to the next.

Sound is transferred through the movement of atomic particles. These can be atoms or molecules. Waves consist of two things. We have compressions and rarefactions. A compression is when particles are forced together. The opposite of that is a rarefaction.

This is when particles move farther apart and their density decreases. You have compression with particles moving together and a rarefaction with those particles moving apart. One compression and one rarefaction constitute a sound wave.

Now, waves of sound energy move outward in all directions from the source. You have a source right here (a source of sound). You have waves moving out in all directions. Actually, if you were to look at what this would look like scientifically, you’d have all these waves coming off of it, but that takes a long time to draw.

Different sounds have different wavelengths. The last thing that you probably should know is that sound is a form of kinetic energy. Now, when I say it’s a form of kinetic energy that’s as opposed to potential energy. Sound isn’t going to be a potential energy, because it’s not energy stored up. Sound is energy in motion, so we call it kinetic energy.

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Last updated: 10/23/2018


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