Dry Ice Crystal Ball
Great Halloween Science It's the world's coolest crystal ball. Create a
soap film on the rim of the bucket and you'll have what appears to be a
crystal ball filled with a cloud-like mixture of water vapor and carbon
dioxide. When the giant bubble bursts, the cloud of "smoke" falls to the
floor followed by an outburst of ooohs & ahhhs from your audience!
Materials
•Large bucket with a smooth rim
•Solution of dish soap and water
•A piece of cloth 18 inches long, gloves, safety glasses
•A few pieces of dry ice
Dry Ice - Grocery stores use dry ice to keep food cold during shipping.
Some grocery stores and ice cream shops will sell dry ice to the public
(especially around Halloween) for approximately $1 per pound. It's a
good idea to take a beverage cooler with you along with a pair of gloves
to protect your hands. If you are planning to perform a number of dry ice
demonstrations, plan to purchase 5 to 10 pounds.
Experiment
Select a bucket or container that has a smooth rim and is smaller than
12 inches in diameter. Cut a strip of cloth about 1 inch wide and 18
inches long. An old t-shirt works well. Soak the cloth in a solution of
Dawn dish soap or use your favorite recipe for making bubble solution.
Make sure that the cloth is completely soaked. Fill the bucket half full
with water. Have tongs or gloves ready to transfer the dry ice to the
bucket.
Place two or three pieces of dry ice into the water so that a good
amount of fog is being produced. Remove the strip of cloth from the
dish soap and carefully pull the strip across the rim. The goal is to
create a soap film that covers the top. It also helps to have the rim wet
before you start. This may take some practice until you get the
technique mastered. Remember that a bubble's worst enemies are
dirt, oil, and rough edges. Your patience will pay off in the long run.
If you accidentally get soap in the bucket of water, you'll notice that
zillions of bubbles filled with fog will start to emerge from the bucket.
This, too, produces a great effect. Place a waterproof flashlight in the
bucket along with the dry ice so that the light shines up through the fog.
Draw the cloth across the rim to create the soap film lid and turn off the
room lights. The crystal bubbles will emit an eerie glow and you'll be
able to see the fog churning inside the transparent bubble walls. Take
your bows as the class erupts in a chorus of ooohs & ahhhs!
Experiment From Steve Spangler Science
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