Light = Sound

Admittedly, I don't know what kind of practical use this understanding has, but it's something that has recently blown my mind. I figure maybe this can trigger an awakening in someone and maybe bring about some cool new technology of some kind. Simply put, it's the realization that sound and light are exactly the same things.

Now, there are some obvious fundamental differences between light and sound, mainly that one is received through visual input (your eyes), and the other is received through auditory input (your ears). However, both can be measured in Herz (or Hz), and they're both made up of waves. There's also differences in the speed at which they both travel (light being MUCH faster).

When you break it down though, you see that light is just incredibly high pitched sound. You'll also find that sound is just very very very deep in the infrared spectrum. As such, you could transpose a musical note and eventually end up with a specific color. How you would do this is figure out what frequency that note is, which we'll use 440Hz, or an A note. To transpose this note you just double it to 880Hz and you're one octave higher, but still on an A, and you can keep doubling this until you reach the visible light spectrum. When you do this you'll see it hit the visible spectrum at 483,785,116,221,440Hz, which turns out to be a reddish orange color.

Again, I'm not entirely sure how this can be applied in a technically useful manner, but maybe you do. I just felt like this theory was very interesting and worth exploring.

Sources:
http://www.ask.com/question/what-is-the-frequency-range-of-visible-light
http://www.flutopedia.com/sound_color.htm