8th Grade Integrated Science
Standard I, Objective 2
Title: Things to Do With Dry Ice
Description: Demonstrations with dry ice are a fun way for students to observe physical and chemical properties of a substance.
Materials: dry ice (can be purchased the morning of the lesson from most grocery stores), Styrofoam cooler, medium sized balloons, hammer or crushing tool, bromothymol blue, phenylthalein, dishwasher soap, metal spoon, candle, pitcher or large beaker, test tube, Styrofoam cup, optional student sheet (see below)
Time Needed: 50 minutes
Background: Explain to students that dry ice is frozen carbon dioxide and that it has the interesting physical property of a low boiling point (-78.5 C). It goes from its frozen state to vapor without passing through a liquid (sublimation) at room temperature.
Procedures:
1. Gather the materials and place them on a demonstration table.
2. You may wish to do the demonstrations and have students watch without doing written work. If you’d rather, give students the student sheet and introduce them to the dry ice. Read the directions with them and tell them how to record the data.
3. Do all or some of these demonstrations. Students can record their findings as you go.
· Crush dry ice and place inside a balloon. Tie off balloon and watch it expand.
· Place dry ice in a Bromothymol Blue solution. The solution should turn from blue to yellow.
· Place dry ice in a pitcher or beaker and let sublime. Light a candle in jar and let burn. Pour carbon dioxide gas into jar with candle and watch it go out.
· Place dry ice in Phenylthalein solution that has been colored pink by adding a small amount of a base. Should bubble to clear.
· Place a spoon over a small piece of the ice and press between the table down. It will squeak.
· Freeze water in a test tube in between two pieces of dry ice. Use a Styrofoam cup to hold the dry ice and test tube.
· Allow students to play “dry ice” hockey by setting up goals on their table and shooting small chunks of ice through them.(by flicking it with their fingers) See if they can explain why the ice “floats” across the table (it is on a cushion of carbon dioxide) Do not give students pieces larger than a quarter, the game ends when the ice is gone.
· Put dishwashing detergent into a beaker of water. Add dry ice and watch the bubbles. Let kids have a handful as they walk out the door.
4. Safety concern: Caution students not to hold the dry ice on their skin or put it in their mouths.
Student Sheet Name______
Title: Things to Do With Dry Ice
Introduction: Dry ice is frozen carbon dioxide. It is called “dry” ice because it goes from a frozen solid to a boiled gas without slowing down long enough to be a liquid. Because of this property, dry ice is interesting to experiment with. You must be careful with dry ice because it is much colder than ice made from water. You should not touch it with your bare skin.
Procedures:
1. Watch as your teacher demonstrates some chemical and physical changes with the dry ice.
2. Record what happens and what evidence you think makes the change a physical change or a chemical change.
3. Answer the questions and write a conclusion.
Data:
Demon-stration # / Chemical or
Physical change? / Evidence
1
2
3
4
5
6
7
Analysis:
1. What is dry ice made of?
2. Why is dry ice different than ice made from water?
3. Fill out the Venn Diagram and compare dry ice to ice made from water:
Dry Ice Water Ice
4. What physical properties do dry ice and water ice have in common?
Different?
5. What chemical properties do dry ice and water ice have in common?
Different?
Conclusion: