Dry Ice

Presented by Lauren Liston

Southwestern University

listonl@southwestern.edu

 

Background Information

Dry Ice is frozen carbon dioxide, a normal part of our earth's atmosphere. In fact, carbon dioxide is the gas that we exhale and the gas that plants use in photosynthesis. Dry Ice is particularly useful for keeping things frozen because of its very cold temperature: -109.3F or -78.5C. Dry Ice is commonly used because it is simple to freeze and easy to handle using insulated gloves. What makes Dry Ice different from the ice that we typically use is that it changes directly from a solid to a gas in a process known as sublimation. Therefore it gets the name "dry ice."

 

Safety Precautions

Always handle Dry Ice with care and wear protective clothes or leather gloves whenever touching it. An oven mitt or towel will work. If touched briefly it is harmless, but prolonged contact with the skin will freeze cells and cause injury similar to a burn. Store Dry Ice in an insulated container. The thicker the insulation, the slower it will sublimate. Do not store Dry Ice in a completely airtight container. If a burn does occur, treat it the same as a regular heat burn. See a doctor if the skin blisters or comes off. Otherwise if only red the skin will heal in time as any other burn. Apply antibiotic ointment to prevent infection and bandage only if the burned skin area needs to be protected.

 

TEKS

Science grade 4

(7)  Science concepts. The student knows that matter has physical properties. The student is expected to:

(A)  observe and record changes in the states of matter caused by the addition or reduction of heat; and

(B)  conduct tests, compare data, and draw conclusions about physical properties of matter including states of matter, conduction, density, and buoyancy.

 

Materials

 

Procedure

THE EXPERIMENT: Get a cardboard box and line it with a garbage bag and put a large block of dry ice in the bottom of the box. If we take a lit candle and carefully put it in with of dry ice laying the bottom, what happens? Does the candle go out? Why does it do that?

WHAT IS HAPPENING: Fires need three things to stay alive. Does a candle need the same things? If you take away the oxygen, what happens? It goes out. If you take away the wax it starves to death. If you take away the heat by blowing on it, the fire cools down and goes out. Some might say the candle goes out because the dry ice is really cold, but if you put you hand in the box and "feel" the Carbon Dioxide gas (be careful to not touch the frozen dry ice). What is? When you put the candle in the box or fish tank with the dry ice, you are putting it into concentrated Carbon Dioxide with very little oxygen. No oxygen...the fire can't breathe and goes out.

 

Helpful Websites:

http://www.dryiceinfo.com/

This website is particularly helpful for teachers. It provides endless information concerning dry ice from safe handling to history, from special effects to traveling and camping plus so much more.

 

http://www.rockitscience.com/dryice.html

This website is great for students. It stresses the appropriate safety precautions for handling dry ice but also has great clipart and fun riddles. This site is good resource for other extension activities. The examples I pulled from this site are as follows:

Magic Balloon: Fill a large balloon with some pieces of dry ice using a funnel. (Remember to wear gloves). You can even add some warm water to the balloon. Tie off the balloon and you will see the balloon look as if it is blowing itself up. If you put enough dry ice in the balloon, the balloon will pop. This is supposed to happen, BUT DO BE CAREFUL. Stand far away from the balloon when it is about to pop.

Soapy Ooze: Prepare to make a mess for this experiment. Do it in a place you won't mind water and soap getting on things. Add some soap to you mixture of dry ice and Hot water. You get a very cool, oozing blob of soap bubbles.

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