First, a Public Service Announcement: As a decade-long former south Louisiana resident who was in Baton Rouge for Katrina, I have some advice. If you’re in Louisiana anywhere south of about Alexandria, now’s the time to start packing. You might be ok sticking around till Saturday night or possibly Sunday morning to see if it turns, but that’s really pushing it. If you’re actually in New Orleans you should leave now regardless. Now to our regularly scheduled post.
Science. On TV it goes something like this: Scientist gets brilliant idea. Scientist goes to lab, puts serious expression on and conducts voodoo-looking ritual involving the lab equipment du jour in a clean and gorgeous lab. Ten-minute experiment provides expected result, confirming brilliant idea. Accolades all around. It’s the CSI model of experimental science.
More typical is what we did last Thursday in my professor’s lab. The first step starts off the same – you need a clever idea. They don’t generally come from flashes of brilliance as much as they do hard work and a lot of thought, but scientists are in the thinking of ideas business and they are pretty good at it. Long story short, this idea involved putting laser pulses through a fluorescent Rhodamine 6G solution. So we set up our optical fish tank (no kidding), poured some solution in it, and fired the laser through it.
One thing I’ll say about laser physics is that the experiments themselves are often very strikingly pretty. I’m going to have to invest in a good camera so I can take some nice pictures and post them here. In this case you have a bright green line running through the solution. Self-focusing effects, thermal defocusing effects, and the motion of the fluid combine to produce an undulating filamentary structure of light which is quite otherworldly.
“It’s very pretty, but I’m not sure we can do anything with it”, said the professor. But the point of the experiment is to find out. So as per the clever idea, we fiddled with some characteristics of the pulsed beam and looked for the solution to behave as we thought it should. One of the two effects predicted worked. The other didn’t. We changed the pulse characteristics. We changed the path length through the dye. We agitated the dye. We got out the spectrometer and measured the characteristics of the beam in the dye – there were two distinct peaks when there should have been one. Or at least there were sometimes – they appeared and disappeared in a way that didn’t make a lot of sense.
We fought with the process for hours, and arguably ended up knowing less about the physics of the situation than when we started. And later on we’ll probably do the whole thing again. And we’ll keep on doing it and thinking about it until we understand it. That’s real science.
Now it’s Saturday, so let’s have a few random items to start the weekend.
A reader emails about a new site called The Graduate Junction, which aims to connect graduate students in collaborative research efforts across many disciplines. Take a look, see what you think.
You probably all read Cocktail Party Physics regularly anyway (and you should!), but this post about Witchblade and the physics of pool is especially neat. The slow-motion video at the end is fantastic.
T-Rex on the wonders of modern science. That pretty awesome “The Future” that all those people in the 50s were talking about? We live in it. We just usually don’t notice.
Have a great weekend, ladies and gentlemen! Tomorrow, a Sunday Function with a result even more bind-bending than the Euler identity.