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Homework Help: What is plasma?

  1. Sep 1, 2009 #1
    I have a basic under standing of what it is but does anyone know in kid-friendly terms of how it is used, what it is and where it can be found?

    Thanks, Chase:smile:
  2. jcsd
  3. Sep 1, 2009 #2
    The most basic definition for plasma is simply an ionized gas. Plasma can be found in many locations. The Earth is surrounded by a plasma known as the solar wind.

  4. Sep 1, 2009 #3


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    This will seem to be picky, but with the bare information about your question, one might ask you, in which context? Biological or physical? If you ask the question to a medical technician, or zoologist, or healthcare assistant, a possibly very different answer might be expected.
  5. Sep 1, 2009 #4


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    As Matt said, (in physics) a plasma is an ionized gas. Basically as you heat up matter (atoms) it goes from a solid (atoms stuck fast to each other) to a liquid (atoms stay in contact but slide around each other) to a gas (atoms bouncing off each other) to a plasma (the atoms bounce so hard that electrons get knocked off and bounce around on their own).

    Since in the plasma (some of) the electrons are kicking around freely electrical currents can flow through it (like in a neon sign) and it is also affected by (and affects) magnetic fields. Solar flares are cause by parts of the sun's magnetic field getting so twisted up by the currents in its plasma that they erupt out into space carrying some of the hot plasm a with them. We get a big gust of hot solar wind if the flare is aimed toward the Earth.

    Since plasma conducts electricity it can block radio waves which is why the astronauts in the older space missions couldn't communicate with ground control during re-entry (re-entry blackout). The atmosphere around the capsule gets heated up to a plasma and its like wrapping the whole ship in aluminum foil as far as getting radio signals in and out. I believe the shuttle missions don't have this problem because there's a gap in this plasma behind them and they can relay communications through satellites from above.

    Those plasma balls you see in novelty shops produce a plasma by pumping the gas inside with high frequency (radio frequency) electricity. This provides enough electrical "kick" to knock off some electrons from the atoms of gas inside. Using high frequency means the electricity doesn't pass through your body (rather passes along the surface) and so it isn't dangerous.

    Plasmas can behave in very complex ways since you not only have the usual gas flow effects, turbulence and such, but also electrical currents and induced magnetic fields. This is part of the way the Tokamak reactors try to acheive fusion. They use the electrical properties of the plasma to keep it isolated from the walls of the reactor. Otherwise they walls are like "ice" cooling the plasma before it can produce enough fusion reactions to keep itself hot and produce energy.

    Hmmm... what else... The northern (and southern) lights are a plasma. It's the solar wind funneling down the magnetic field lines of the earth near the poles until it collides with the air to produce pretty lights. Magnetic fields block plasma from blowing perpendicular to the them. If it wasn't for the Earth's magnetic field the solar wind would little by little blow off our atmosphere into space. As I mentioned above a solar flare can hit the Earth but it is blocked by our magnetic field. But it can hit with enough punch to cause the magnetic field to bounce around a bit and this causes problems dound here on the surface especially with electrical power lines.

    So a plasma is basically just gas but with this extra electromagnetic component due to the ionization which makes its behavior much more interesting.
  6. Sep 2, 2009 #5


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    Blood plasma is basically just a liquid :wink:
  7. Sep 2, 2009 #6
    Very good response jambaugh.

  8. Sep 2, 2009 #7
    Thanks so much!!!!

    i love this site :D
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