[meteorite-list] How to make a Kitchen Comet -----------O

From: Dave Mouat <dmouat_at_meteoritecentral.com>
Date: Thu Apr 22 10:02:24 2004
Message-ID: <3C80FC6D.2186C458_at_dri.edu>

Use very hot water andpour it into the CO2 not the other wayaround.
Point a strong electric fan at your mass and, voila, you have the sun
and the tail

Rick Nowak wrote:

> How to make a Kitchen Comet
>
> You can make an accurate model of a comet nucleus
> easily and inexpensively. Unfortunately it is
> difficult to do neatly.
> Here is what you need:
>
> 1. Five pounds of dry ice. You can get this from ice
> companies or ice cream parlors. CAUTION: Dry ice is
> -79 degrees C (-110 degrees F). Any more than a brief
> exposure will cause 'burns". Be careful when handling
> it.
> 2. Water: Around half a gallon in a pitcher.
>
> 3. Ammonia: A few drops or sprays of window
> cleaner.
>
> 4. Dirt: Fine grained, about one handful.
>
> 5. Corn Starch or Worcester Sauce: Just a couple of
> pinches or drops.
>
> 6. Trash Bags: Two large bags.
>
> 7. Large Bowl or Small Pot
>
> 8. Water Proof Gloves: The better insulated the warmer
> your hands will remain.
>
> 9. Cloth Towel.
>
> 10. Paper Towels: One small roll is plenty.
>
> 11. Hammer.
>
> 12. Mixing Spoon or Stick.
> These ingredients are either actual components or
> handy analogous ones. The dry ice is frozen carbon
> dioxide. Water, ammonia, organic (carbon based)
> molecules, and silicates are all present on comet
> nuclei. They have been identified through spectral
> measurements of comet tails and the collection of tiny
> ice particles by very high flying research aircraft.
> Here is the Recipe:
> Line the bowl with a trash bag. Place the other trash
> bag on the floor. Pour about a pint of water into the
> bow. Add the corn starch or Worcester sauce, ammonia,
> and some of the dirt. Mix a bit.
> Put on the cloves. Wrap the dry ice in CLOTH towel.
> Place it over the trash bag on the floor. Use the
> hammer to grind up the dry ice into a powder.
> Gradually poor the dry ice powder into the water,
> mixing as you poor. There will be lots of vapor
> formed. The dry ice, water and other ingredients
> should form a thickening slush. Keep stirring for a
> few seconds as it thickens.
> Now, using the trash bag to lift the slush away from
> the sides of the bowl, use your gloved hands to pack
> the slush into a ball. Keep packing and forming until
> the ball solidifies as a big lump.
> Peel back the trash bag. Scatter some more dirt over
> the lump. Pour some of the remaining water over the
> lump, turning as you do so, so that a layer of water
> ice forms over the entire lump.
> Observe the behavior of your miniature comet nucleus.
> It can be handled without gloves if the water ice
> coating is intact. If a spot feels sticky, pour water
> on the spot. It hisses and pops as carbon dioxide
> sublimes (goes from the solid state directly into a
> gas) and forces its way through weak spots in the
> water ice crust. On real nuclei this results in
> slight jetting forces that can cause the nucleus to
> spin, slightly alter its orbit, or spit apart (or
> "calve").
> Note: Get about three or four pound of dry ice for
> each nucleus you plan to make. You can purchase it
> the afternoon or evening prior to the demonstration
> and store it in a freezer or ice chest. Place an inch
> or so of newspaper below the cry ice to prevent
> cracking to the surface on which it rests. Try the
> demonstration first to an idea of the correct amounts
> of water to use.
> It's fun, it's a mess, and it's one of the most
> memorable and scientifically accurate demonstrations
> in astronomy!
>
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Received on Sat 02 Mar 2002 11:23:09 AM PST