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Thursday, March 21, 2013

Solid, Liquid, Gas, or Plasma?

Most week days  I drive my two kids to day care and I try to be educational in the car. What can I say - its a professional interest. One morning we got on to states of matter and it got me musing. What are the definitions of the different states? How do you test for the state of matter?

NASA has the most concise and simplest explanation I've seen, even if it was written in 2006. It is not the most extensive but it answers my question on how to test for states of matter. It also addresses the issue of plasma - the "fourth state" of matter. There is plenty to read on plasma including this "Plasma Cannon Safety Activity Book" by the makers of Schlock Mercenary (there is a link on the right). But the thing I liked most about the article was NASA's comment, "NASA is currently doing research into the use of plasmas for an ION propulsion system." Do you know what uses twin ion engines to fly? I'll give you a hint - Twin Ion Engine is an acronym. Turns out that NASA is already implementing the NEXT generation of ion engines to meet our propulsion needs. Now to develop an X-wing.

I kind of touched on the states of matter when I talked about setting fire to the snow back in January. I used to think that the states were steps to progress through, but I was clearly mistaken. Snow is when water goes from gas to solid without mucking about in the shifty liquid phase. Also, I always wondered why you never saw liquid carbon dioxide. You ether have what you breathe out of your lungs or what you use to make ice cream. It turns out that in order to see liquid carbon dioxide you need a very large, very think, very clear sapphire. So movement between the phases may be triggered by a variety of things (not just temperature) and does not need to happen in a liner process.

It occurred to me that the states of matter are also represented in the classic elements of Earth, Water, Wind, and Fire. Apparently that is a common thought - or at least common enough to end up on Wikipedia (first paragraph). But I wonder how many came to that thought from Avatar: the Last Airbender. I'm not talking about the movie which had one of the highest CinemaSin scores ever, but the cartoon which is well worth watching.

So here is the question - Why should we care about the phases of matter? Why do I try to teach them to my children? Why is it considered basic science knowledge that people should know? Probably because it is - basic science knowledge that is. A basic understanding of the sciences is important to have as science dictates how the world works. Perhaps that was a bit strong - science describes how the world works. The more you know about something the more you can use that information. For instance, before people understood gravity (the force that holds us down) they couldn't fly.

Now isn't that interesting?

One last thought - Water is the only composition that is not only found naturally in the three main states, but that are consumed in all three. Particularly in hospitals. Heck, they even use plasma - both kinds. Just make sure they use the right one in you.

March 26 / 2013 Update - Web comic KXCD in it's weekly What if blog makes mention of ION engines in the retrieval of the Voyager I probe. Of course NASA is not going to retrieve Voyager I, but it's cool to hear about ION engines.

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