Transcript Dry Ice Background

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