Differential Heating of Ambient Air and CO2
In this experiment, we examine/demonstrate the warming of air when the CO2 concentration is
increased.
In one of the jugs, there is just plain air. In the other jug, there is air and additional CO2 that we
add using a CO2 corkscrew cartridge. Then the two jugs are put in front of a light/heat source
(the light bulb) and warmed. The result is that the jug that contains extra CO2 warms more
quickly and to a higher temperature than the jug with just plain air.
This experiment models what happens in the Earth’s atmosphere. As humans have been adding
CO2 to the atmosphere, we have observed that the Earth’s atmosphere has been steadily
increasing in temperature.
Materials Needed
2ea 1-Liter empty water bottles, with 3/16” hole drilled in center of each cap
Small pieces of modeling clay
2 electronic instant-read meat thermometers
Ring stand and150W incandescent work lamp with clamp
Timer
Student Activity Sheet
Hypothesis: When the bottles containing ambient air and carbon dioxide are heated equally by the work
lamp…(complete the sentence, explaining what you think will happen) ___________________________
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Procedure:
1) Prepare the bottles a few minutes before the activity. With the cap off one bottle, fill the bottle with
carbon dioxide from the CO2 cartridge, driving out most of the air. Cap the bottle immediately, and
insert the meat thermometer probe through the hole in the cap. Fill any gap in the hole with a piece of
modeling clay.
2) Insert the second probe thermometer through the cap on the second water bottle, and fill any gap with
clay. Turn on the thermometers, and after one minute, record the temperature inside each bottle on the
data chart included with this activity.
3) Place bottles equally distant from the work lamp, and set the timer to zero. Turn the work lamp on and
start the timer running at the same time. Record the temperature in each bottle every 1 minute for 20
minutes.
Observations and Data Collection:
Write two to four observations, things you notice while conducting the activity. Make sure your
observations are related to this activity. Write in complete sentences.
1) ______________________________________________________________________________
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2) ______________________________________________________________________________
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4) ______________________________________________________________________________
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4) Work in teams of two, one team working on ambient air, and one team recording data for CO2. Record data in the charts below.
When your team is finished recording, trade data with the other team, and copy their data on your own chart.
Data for Ambient Air
Minute
Temp ◦C.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Data for CO2
Minute
Temp ◦C.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
5) Now you’re going to produce a graph of both sets of data on the same grid. Be sure to use all the elements of a good graph.
What kind of graph will best show the changes that took place during the activity? __________________________________________________
Explain why you chose this kind of graph.___________________________________________________________________________________
Title: ___________________________________________________________________
Analysis:
1) Explain the differences between the graphs for the two bottles. ___________________________
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2) Your answer to question #1 helps provide evidence for what scientific phenomenon?
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3) Does the activity support or refute your hypothesis (don’t change your hypothesis if you found
out it was incorrect)? State your conclusion: __________________________________________
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4) About 0.04% (about 100 of 1%) of the Earth’s atmosphere is composed of carbon dioxide, while
the contents of your bottle is nearly 100% CO2. What questions does this activity spark for you
about the effect of carbon dioxide on the temperature of the Earth’s atmosphere? Discuss this
with your elbow partner, and write four or five investigable questions about CO2 in the
atmosphere. Be ready to share them with the class.
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