Creative Science Tutorial for Children at Home

(Parental Guidance is Advised)

Composed

By

HARRY KOCHAT

Drug Discovery & Development Operations
BioNumerik Pharmaceuticals, Inc.

 How to use these pages

This site is intended to be a resourceful warehouse with variety of projects to serve youngsters with creative minds towards scientific projects. It is a sort of warped semi-scientific cookbook of tricks, gimmicks, and pointless experimentation, concoctions, and devices, using, for the most part, things found around the house. You may appreciate your hidden creative talents if you happen to involve with these building blocks and consider yourself a better person for it once you learn it.

These are vintage projects, most of which appeared in many different books and publications from the 1930's through the 1960's or time and again I demonstrated to student groups actively involved in their gifted programs . They have for the most part been adapted for contemporary audiences. Most components are readily available; I have included these projects because they are part of the heritage of "Creative Science at Home".

PART 1

crystal gowth.gif (8287 bytes)Crystals on a string

A variety of fairly common substances can be used to grow crystals, including:

 

Salt
Epsom salt
Sugar
Borax
Alum (aluminum potassium sulfate)
Photographer's hypo
Bicarbonate of soda (baking soda)
Laundry soda
Copper sulfate

In a jar add to very hot water whichever substance you are working with until saturation is reached. Pour the solution off into a clean jar, leaving behind any undissolved substance.

Suspend a thin thread into the center of the jar. The thread can be tied to a pencil, Popsicle stick, or whatever is handy and will span the jar opening. Alternately, you can punch a hole in the lid of the jar, pass the thread through the hole, and then use a nail or pencil to hold the thread in place from the outside. If you are using the jar lid, screw it on, and stick a piece of masking tape over the hole. If you are not using the jar lid, tape a piece of paper over the mouth of the jar. This is to control the rate of evaporation.

Let sit, then after 15 minutes, swish the jar a bit. Swish it again 15 minutes later, then one final time an hour later. Set the jar where it won't be disturbed. Depending on the substance used, the crystals should begin to grow in an hour or so, and continue to grow for from a day to several days. Old-fashioned rock candy is grown using basically the same setup as above. Sugar is used for the solution, and the crystals are typically grown on a wooden stick rather than a thread.

Growing a single large salt crystal

With a little more effort it is possible to produce a single large symmetrical crystal. First fill a jar with hot water, and stir in as much salt as will dissolve. This is a supersaturated solution. Allow the excess salt to settle out, and pour the mixture into a saucer, leaving all of the undissolved salt behind. As the water cools, tiny crystals will begin to form on the bottom of the saucer. These are the "seed" crystals. Using a magnifying glass, pick out the largest perfectly formed crystal.

Hold on to any well shaped seed crystals in case your first attempt does not go well. Mix up another batch of hot supersaturated solution. Allow the undissolved salt to settle out as before, and pour off into a clean jar. You can use a coffee filter or clean napkin as a filter. Tie a thin thread to the seed crystal and hang it in the solution. Cover the jar with a piece of paper to slow evaporation. As the water evaporates over the course of several weeks, the salt will attach to the growing crystal. Remove any other crystals as they form. From time to time, you should add more cooled, supersaturated solution. Don't let the jar get too warm, as this may dissolve the crystal. Crystals formed this way tend to be very fragile, and of course will be dissolved by water. This can be tried with other substances, such as bicarbonate of soda, alum, copper sulfate, photographer's hypo, borax, laundry soda, etc.

crystal in a jar.gif (7041 bytes)Growing one big alum crystals

Heat one cup (250 ml) of water to boiling. Stir in about 3 tablespoons (45 ml) of alum until it dissolves. Pour the solution into a clean jar. Cover with plastic wrap or wax paper and set in a place where it will not be disturbed for several days. If the solution was pure enough, you should end up with a single large crystal.

Charcoal Crystal Garden

This is the classic way I demonstrated to a touring school group in my work place.

Materials you need

Charcoal briquettes (or brick pieces or small porous stones)

Water (pref. distilled)

Pie plate (non-metal)

Salt - not iodized

Ammonia

Bluing

Food coloring (optional)

Whack the charcoal into smallish bits (don't pulverize it - you want one inch (25 mm) or so chunks). Spray them with water until they are soaked. Put them in the pie plate, using enough for an even layer.

In a jar, mix

3 tablespoons (45 ml) ammonia

6 tablespoons (90 ml) bluing

3 tablespoons (45 ml) salt

Make sure it all dissolves. Dampen the charcoal with it. Add a little water to the jar - a couple of tablespoons (30 ml) - and swirl out the rest of the chemicals. Put this on the charcoal. Drop food coloring here and there (whatever isn't colored will be white). Sprinkle with a couple more tablespoons (30 ml) of salt. Set aside. On days 2 and 3, pour a mixture of ammonia, water, and bluing (2 tablespoons - 30 ml - each) in the bottom of the pan. Afterwards, leave it someplace where it won't get messed with (cat proof) until you have crystals (2 days to 2 weeks depending on climate). The crystals will be very fragile. Bluing isn't as easy to find as it once was. Check a grocery store in an older neighborhood, or in a smaller town. If you find powdered bluing instead of liquid bluing, it can be substituted if you mix it app. 1:1 with distilled water. Also, this project works well substituting bits of sponges for the charcoal briquettes.

Charcoal Crystal Garden, an alternate method

Put several pieces of charcoal briquettes in a bowl.

Mix:

1/4 cup (60 ml) water

1/4 cup (60 ml) laundry bluing

1/4 cup (60 ml) table salt

Tablespoon (15 ml) ammonia

Stir well and pour over the briquettes, making certain they are sticking up from the liquid. If you want, drop mercurochrome, colored inks, or food coloring here and there. Wait for the crystals to grow.

Salt Garden

Place pieces of charcoal, brick, or small porous stone in a dish. Stir salt into warm water until no more salt will dissolve. Add a spoonful of vinegar to the solution, and pour it over the charcoal or stones. The vinegar will degrease the stones, allowing capillary action to carry the salt water to the surface, where it evaporates, leaving salt crystals. Capillary action continues as long as there is solution remaining, which is carried up through the new crystals, building on top of them.

Acknowledgement: The Composer and the publisher sincerely thank the author, Mr.Brian Carusella for providing the allowance to utilize the essence of the aforestated scientific information: http://freeweb.pdq.net/headstrong/default.htmContents © 1998 Brian Carusella All original rights reserved


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