View Full Version : Growing Stalactites and Stalagmites

28-12-2004, 14:10
Growing Stalactites and Stalagmites

Ever been in a cave and seen all the beautiful dripping formations? The columns, stalactites and stalagmites grow over the centuries as lime is dissolved out of the ground by rainwater, then slowly deposited again by the water as it drips into the cave. Remember, stalactites (with a "c" in the middle) grow from the ceiling of the cave, and stalagmites (with a "g" in the middle) grow up from the ground. When they meet, a column is formed.
You can create your own cave formations with this experiment.

You will need:
2 empty pint jars to hold the solutions
a strip of absorbent cloth like an old towel, about one inch wide and 18 inches long, this will act like a wick
measuring cup and spoon
hot water
tray, or cookie sheet to catch the many drips
10 tablespoons of washing soda (sodium carbonate), it can be found in larger grocery stores in the laundry soap section

Do this: Wash and rinse the jars with hot tap water. Pour one and a half cups of hot water into each jar. Add 5 tablespoons of washing soda to each jar, and stir until the soda is dissolved. Put the towel strip in between the two jars. The towel will begin to drip. Your "formations" will begin to grow, and if you are patient, they will meet and form a column. There is a lot of dripping, put this experiment in a place where it won't cause a mess.

Setting the experiment by the wood stove made it grow faster. The stalactite grew fast when the water level got down almost to the level equal to the bottom of the sag of the towel strip. When it dripped fast at first, all the solution dried on the bottom of the pan. After the solution got below the level of the center of the towel, the strip of fabric got very stiff, and crystals began growing in the jars. The solution needed more water. When I added more water, the towel began to drip again, and quickly dissolved my column!

Another way to form a stalactite is to use a dropper, and put one drop of solution at a time on a saturated wick. Let it dry, and next time you pass by, add one or two more drops, just until it almost drips again. The object is to create a hanging drop of solution, which will dry and form the stalactite. Repeated applications will grow the formation.

Chemistry note: Baking soda (that you put in cakes and cookies) is sodium bicarbonate. Washing soda is slippery, soapy sodium carbonate. Lye or caustic soda is sodium hydroxide. Stay away from the lye, it is very dangerous.

28-12-2004, 14:12
Growing a crystal garden

You will need:
a plastic container, like a large margarine tub
pieces of charcoal, pieces of broken clay flowerpots, and bits of sponge
liquid laundry bluing*
household ammonia (Ammonia is an irritant. That means it will stink your nose off. Keep it away from your face.)
a plastic cup
a tablespoon
Day One:
Put the charcoal and the fragments of pot and sponge into the butter tub. Soak these parts in water for 15 minutes, then drain. Sprinkle over the fragments:
2 tablespoon of water
2 tablespoons of salt
2 tablespoons of bluing

This tub full will look pretty terrible at the beginning.

Day Two:
Sprinkle on two more tablespoons of salt. It will still look terrible today.

Day Three:
In the plastic cup, mix together 2 tablespoons of salt, 2 tablespoons of water, 2 tablespoons of bluing, and 2 tablespoons of ammonia. Stir well and carefully pour the solution into the bottom of the container - not on the crystals. It still will look and smell like a horrible blue glop, but then it begins to change....

Now what happens???
When your crystals stop growing, mix up another batch of solution like you did for day number three, and spoon it onto the materials. New crystals will form. You may also try adding some drops of food coloring or watercolors to your garden.

I can't show you any pictures of what was growing in my crystal garden. I had a row of crystal experiments lined up on the back porch, and our neighbors' dog ate them....

28-12-2004, 14:13
And to mention eating crystals, one of the most famous recipes for crystals is one YOU can eat:

Rock Candy

Dissolve 1 1/2 cups sugar in 1/2 cup boiling water. This is a thick, hot syrup. It will burn you and keep on burning your skin because it is sticky, so be *very* careful not to spill it on yourself! We put our solution in a 1 1/2" deep tray, and suspended crochet twine from chopsticks for the crystals to grow on to

28-12-2004, 17:14
Neat recipes, spirit!

Thanks :D

makes me want to try them out... especially the crystal garden. I might just do that when I get back from my end-of-year trip abroad.