Dry Ice Experiments for Schools, Teachers & Students

Dry Ice ExperimentsDry ice is fun for teachers and students to use for school science experiments. With very simple experiments, you can see and understand the many wonders of dry ice and carbon dioxide. That mysterious fog that you see on TV and in movies is made using dry ice. Bubbling witch's brew and colorful “mad scientist” liquids boiling on a laboratory bench are special effects done with dry ice and water.

It's simple to create amazing effects using dry ice. At left is a plastic jar of water with blue food coloring and a piece of dry ice.  The thick blue substance at the bottom is clear Kraft™ Karo Syrup™, which is denser than water, so it sinks to the bottom, encasing the dry ice.  As the dry ice sublimates, [see below for definition of sublimation] it creates interesting mysterious blue bubbles in the syrup and water along with fog spilling out over the jar.

 

What is Dry Ice?

Dry ice is solid carbon dioxide. Dry ice doesn't melt into a puddle like wet ice that's made by freezing water. Dry ice goes directly from a solid into a gas, which is called sublimation. We say that dry ice “sublimates” instead of melting. The process is called "submlimation." When dry ice sublimates, you won't see a puddle, but you might see a cloud.

It Fills the Room

The gas that dry ice forms when it sublimates is carbon dioxide or CO2. Because dry ice expands so rapidly into carbon dioxide gas, it's dangerous to use dry ice in a small room or in a small space that does not have good ventilation. As the dry ice sublimates, the room or space fills with carbon dioxide gas produced by the dry ice. If people or animals breathe too much carbon dioxide gas, they will suffocate because their lungs cannot get enough oxygen. Be very careful when using dry ice indoors.

It's Really Cold

Because dry ice is so cold (-109 degrees Fahrenheit), you must never touch it with your bare hands. You could get frost bite from dry ice which causes a “burn” on your skin just as if you were burned by fire. Always use insulated gloves when touching dry ice. Use dry ice only with adult supervision and always wear skin and eye protection. Never play with dry ice in your hands and never put dry ice into a tightly-closed container or in your mouth or clothes.

Let it Escape

At any temperature above -109 degrees Fahrenheit, dry ice goes from a solid that takes up very little space into a gas that expands to fill whatever space is available. This is an important fact to remember when storing dry ice. You should never put dry ice into a container in which gas cannot escape quickly. The expanding carbon dioxide gas will cause a closed container to explode which can cause injuries.
Dry Ice is kept in a cooler, but don't close the lid tightly

Storing Your Dry Ice

You can store dry ice for school science experiments in an insulated cooler as long as the top isn't put on tightly. To keep dry ice from sublimating or disappearing too quickly, you can use insulated gloves to wrap it in layers of newspaper or you can use Styrofoam to insulate dry ice from the warmer air outside the cooler.

It's not a good idea to store dry ice in the freezer section of a refrigerator because air circulates constantly in the freezer. Air currents passing over the dry ice cause it to sublimate faster than if it were in a completely still place without wind or air currents.

Dry Ice and Balloons

Dry Ice can blow up balloons by filling them with carbon dioxide as dry ice sublimatesBlow up a balloon using dry ice!

How could something as cold as dry ice blow up a balloon?

Remember that dry ice expands as into carbon dioxide gas when it sublimates. This experiment shows you how that works.

What you need for this experiment:

  • Balloons with openings large enough to fit a plastic bottle opening
  • Empty plastic soft drink bottle
  • Small pieces or large pellets of dry ice
  • Tongs to hold the dry ice
  • Two people

What to Do:

  1. Blow up one of the balloons and tie it off.
  2. Save the balloon for later.
  3. Remove the lid of the plastic bottle.
  4. Have one person hold the plastic bottle upright.
  5. With tongs with insulated gloves, take a few small pieces of dry ice and put them into the plastic bottle.
  6. Fit a balloon over the opening of the bottle.
  7. Watch the balloon inflate with carbon dioxide as the dry ice sublimates.
  8. To make the balloon inflate faster, shake the bottle gently. Remember how we said that air currents make dry ice sublimate quicker into carbon dioxide?
  9. When the balloon is fully inflated, remove it from the bottle and tie it off.
  10. Go and get the first balloon that you blew up with your own breath.
  11. Toss up both balloons into the air.

Notice how the balloon filled with carbon dioxide gas falls quickly to the ground?

That's because carbon dioxide is heavier than air.

With insulated gloves and using tongs, pick up a piece of dry ice and touch it to the balloon that you blew up with air [not the one you filled with carbon dioxide]. What happens to the balloon?

Can you guess why?

Alternative Experiment - Inflate a latex glove

Using insulated gloves and tongs, place a small piece of dry ice into a thin latex glove like the ones used for medical examinations. Tie off the end of the glove, shake it gently, and watch it inflate just like a balloon.

Check back on this web site for more Experiments with Dry Ice.