Sound

Sorry but this is a lame blog post. Didn't have much time to do anything this weekend so all i could think of was the sound equalizer on my cell phone which looks like this:

It's hard to see but all those bars have a number under them. 80 and 420 Hz and 1.4 and 3.7 kH. These are measures of frequency and thus also measures of wavelength (tone) as they are inversely related. I can change the levels of different frequencies in this way and change the sound of whatever i'm listening to. That's it.