Satanic sulfur hexafluoride and other fun stuff

One of the most basic topics (no, that was not a pH pun) introduced to someone learning chemistry is the states of matter. As we know, or I hope you know, the three states of matter are solid, liquid and gas. Solids have a distinct shape, and the particles of each solid are packed uniformly together. For liquids, the particles are spaced out and may flow past each other allowing liquids to take the shape of any container they are in. Gases are spread out much farther than liquids therefore allowing them to occupy an entire container in which they are placed in. One of the things that heavily depends on the states of matter is sound! A common example of this is five-year old children who breathe in helium from balloons to have very high voices. Watch this video by the show, Mythbusters, to explain this trick. As stated in the video, don't try this at home.

     Like Adam states, helium causes your voice to sound high because sound waves are capable of traveling through it much faster due to its lesser density. This effect is reversed when used with sulfur hexafluoride, a very dense gas. Based on this information, most of my childhood makes sense now! You first breathe in the gas, like helium, which is then exhaled as you talk. Sound waves from your vocal cords travel in this exhaled gas which gives the change in the sound. This is also why over time, the effect of the gas wears of as your lungs exhale all of the gas. Imagine if our atmosphere consisted mainly of sulfur hexafluoride! That'd be a scary world. 

       The basics of sound travel are explained on the first page of this article. Ignore the rest of the article, for I do not care whether I can hear sound in space or not. http://science.howstuffworks.com/humans-hear-in-space1.htm   As stated in the article, sound is a form of energy transmitted through a medium. Thus the movement of the disturbance (the thing making the noise) will generate the sound waves which collide with particles of a form of matter, such as gas. These particles of matter such as gas would then collide with each other repeatedly which would transmit the sound across a distance. We hear sound when air particles transmit these sound waves to one another until they finally reach our ear drum. The brain then decodes these vibrations. 

       By studying chemistry, the seemingly simple subject of sound can be explained. From a small age, we know our bodies can generate sound and hear it as well. Though we knew this, we never knew on our own this sound was made possible by the repeated collision of particles transmitting sound to our eardrums. If you did know this on your own, well then you should go find Stephen Hawking because you are a genius. The article uses the example of hearing vibrations by tapping on a table with your head against it. How many times have we done this while having no clue why this was possible. This is why we study chemistry, to have a logical, coherent explanation to the phenomenons of life. I wonder how the speed of sound in hydrogen, the lightest element, compares to the speed of light. So the next time you hear a good song, if you really wanted to be cool, you could say "This collision of air particles is quite enjoyable!"