Hi Rick and All, The Kitchen Comet activity you list is a good one. In fact, I have done it three four times in the past month. Students and teachers love it. Here is a link to where it is located within the STARDUST educator's guide.
Click the link, then scroll to the Comet Basics: Cookin' Up A Comet activity. http://stardust.jpl.nasa.gov/classroom/guides.html Comet Basics (PDF File - 127KB - 11 Pages) * Activity: Cookin' Up A Comet Cheers, Martin On 3/2/02 6:30 AM, "Rick Nowak" <[EMAIL PROTECTED]> 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! > > > __________________________________________________ > Do You Yahoo!? > Yahoo! Sports - sign up for Fantasy Baseball > http://sports.yahoo.com > > ______________________________________________ > Meteorite-list mailing list > [EMAIL PROTECTED] > http://www.pairlist.net/mailman/listinfo/meteorite-list ______________________________________________ Meteorite-list mailing list [EMAIL PROTECTED] http://www.pairlist.net/mailman/listinfo/meteorite-list
