1. Dry Ice Lab Purpose: Observe changes in state from solid to gas.

2. Background: Dry ice is carbon dioxide in its solid state. Remember…dry ice sublimates instead of melting. Carbon dioxide is found in the earth's atmosphere Humans exhale carbon dioxide gas and plants use it for photosynthesis. Carbon dioxide is a colorless, odorless, and tasteless compound. Dry ice is -78 degrees Celsius (-109 degrees Fahrenheit) On your lab report: Summarize at least 2 facts about dry ice using your own words. Define sublimation

3. Safety For Dry Ice Lab Do NOT touch dry ice with your bare hands, it can damage your skin. Dry ice will BURN exposed skin!!! Use the plastic tongs to touch and move the dry ice. Wear your safety gear: aprons and goggles Long hair must be pulled back. Do NOT inhale the gas.

4. Safety (cont.) Use caution when lighting the candle. Make sure the area you work in is well ventilated. Do NOT close the doors. Do not place dry ice or dry ice and water in a sealed plastic bottle or thin glass bottle. It will explode. People can be severely injured. It is against the law and it is a felony.

5. Divide your paper into 4 sections Each individual lab within this activity has its own procedure. We will step through these as a class using this presentation. No one is allowed to move ahead until we are all ready. In each section record: Hypothesis (if…, then… format) Observations (answer questions) I don’t know is not an acceptable answer. Make an educated guess.

6. Hypotheses and Observations: Experiment 1 H: If I touch dry ice to metal, then… O: What? Why? Experiment 2 H: If I put a flame next to dry ice, then… O: What? Why? Experiment 3 H: If I put dry ice in warm water, then… O: What? Why? Experiment 4 H: If I put dry ice in warm soapy water, then… O: What? Why?

7. Experiment 1: Screaming Metal Materials: lab spoon, Petri dish, dry ice. Procedure: Place the metal spoon against the dry ice in the Petri dish. Be careful not to let the spoon get too cold, you could get frost bite. Results: What happens? Why do you think this happens?

8. Experiment 2- Magic Fire Extinguisher Materials: beaker, dry ice, match, candle, clay, small pie tin. Procedure: Place the dry ice in your beaker. Light the match and light the candle. Place the candle near the dry ice. Results: What happens? Why do you think this happened?

9. Experiment 3 – Spooky Fog Materials: 100 ml of hot water, glass beaker, dry ice. Procedure: Place 100 ml of hot water into the beaker. Add some dry ice. Results: What happens? Why do you think this happens?

10. Experiment 4 – Soap Ooze Materials: the spooky fog, 10 ml of liquid soap. Procedure: Add the10 ml of soap to the spooky fog experiment. Results: What happens? Why do you think this happened?

11. Clean Up Clean out the beaker really well so that it’s not soapy for the next period Dry off the trays Put lab trays back on the counter

12. Conclusion – Address the following questions using paragraph format 1.What is sublimation and how is it different from melting? 2.What is needed to cause a substance to sublimate? 3.Where is the thermal energy coming from to cause the dry ice to sublimate? 4.Is sublimation a physical or chemical change? Explain your answer.