Sunday, August 10, 2008

Lightning in a Jar

When I find an interesting link, or site or whatever in my cruising around the ISH (Information Super Highway), I copy the URL and a brief description over onto a notepad document I call "notes." These items are things that I want to post, so I don't have to track back to find them again- I just have to copy the information from the document into the composer. That does make it easier and more efficient, but I'm still falling behind- I have pages of notes of stuff that's now hopelessly outdated. Today I'm just trying to get some of that stuff caught up.

Since I have just posted another piece on lightning, this seems like an approprite place to put this vid clip- lightning in a jar. Technically, it's plasma, the fourth state of matter. Plasma is like gas (fluid and compressable), but the atoms and molecules that make it up are ionized- that is, the atoms and molecules are charged and there are free electrons flying around. This has a number of consequences: 1) the gas conducts electricity; 2) the gas is strongly influenced by magnetic and electric fields; 3) when an electron rejoins a charged atom or molecule, it gives off a photon (light), so plasma glows.

The previous post's video of a lightning strike shows points 1 and 3 very well. This picture of the August 1 eclipse shows point 2 well- the streamers of plasma in the corona are shaped by the Sun's magnetic field. (Bigger version here, and click the pic for a huge version. Since the picture is a composite of 28 images, the medium-sized version is actually the most impressive to me) Since plasma is conductive, as long as there is a charge difference between two regions in the plasma, electrons will flow from the negatively charged area to the positively charged area, keeping the plasma ionized. If you could get a plasma started in a microwave oven, the charges imposed by the action of microwave radiation on an ionized material would sustain the plasma for as long as the microwaves were hitting the glowing gas. Probably not a good idea, but fun to watch someone else do it. Unless, of course, you're this guy's girlfriend or wife. What in the hail are y'all doing?"

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