I made it to Charlottesville, and am all checked in to the Econo Lodge, which is a little more Econo than I was expecting. It’s an old-school motel, with rooms that open right into the parking lot, the sort of place where the towels are tiny and scratchy, the pillows and mattresses are thin, and the tap water tastes like cigarette smoke. Still, it’s not like I’m going to be doing much more than sleeping here.
I promised some entertainment in my absence, so this seems like a good time for a Dorky Poll. I’m going to be spending a lot of time over the next few days listening to talks about the interaction between light and matter, so here’s an esoteric question:
Which do you prefer: transverse waves, or longitudinal waves?
As always, leave your answers in the comments. If you’re confused about the question, I’ll put some explanation below the fold.
Waves are a disturbance in some medium (using a broad definition in which “the electromagnetic field” counts as a medium), and there are two main types of disturbance: the disturbance can be in the direction of motion of the wave (“longitudinal”), or perpendicular to it (“transverse”).
Sound waves are logitudinal. When you hit a wrong key, the speaker in your computer vibrates back and forth, pushing the air molecules next to it back and forth. These bump into air molecules a little further out, which bump into molecules further out, and so on until the wave reaches your ear. None of the molecules move all that far, but they shift back and forth a little bit along the line between the speaker and your ear.
Light waves are transverse waves. If a light wave is moving from left to right, it creates an electric field that oscillates up and down, and a magnetic field that oscillates in and out of the page (assuming, of course, that we’re in a classical limit where it makes sense to talk about light as a wave…). Particles set into motion by the wave will move in a direction perpendiculr to the line between the light source and your eye.
So, those are your choices. Which sort of wave do you like better?