# Sound

Sound is a pressure disturbance that moves through a medium, in the form of mechanical waves and these mechanical waves transfer energy from one particle to the next.

This here, sound needs a medium to travel through and so that could be something like air, water or some other matter.

Mini-test: SOUND
Question 1: Sound moves through a medium in the form of
A.
B.
C.
D.
Question 2: You hit a cymbal and then grasp it tightly between your fingers. What is most likely to happen?
A.
B.
C.
D.

Next Lesson: Speed and Velocity

The transcript is provided for your convenience
But either way, sound has to have a medium to travel through and then the reason it needs to travel through something, because it’s transferring energy from one particle to the next.

Now, another thing you need to know about sound is that sound is transferred through vibrations. Vibrations transfer energy to adjacent particles. Now, 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. But actually, the particles aren’t moving and so the vibrations transfer energy from one particle to an adjacent particle and that way, sound moves out through the waves and other areas. But actual matter is not moving with the sound, the sound is just moving from one particle to the next and so sound is transferred through the movement of atomic particles and so these can be atoms or molecules.

Now, waves consist of two things, we have compressions and rarefaction, so a compression is when particles are forced together and so the opposite of that is a rarefaction. This is when particles move farther apart and their density decreases, so you have a compression with particles moving together in a rare fraction with those particles moving apart. One compression and one where a fraction constitutes 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 and so you have waves moving out in all directions. Actually here to look at what this would look like scientifically, you have all these waves coming off it and it takes a long time to draw and so different sounds have different wave lengths.

And then the last thing 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, which 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.

Next Lesson: Speed and Velocity