SNC2D/2P Climate Change/Earth’s Dynamic Climate Teacher Demo: Greenhouse Effect Topics Timing greenhouse effect
atmosphere
climate
climate change
preparation: 5 min
activity: 20 min
Specific Expectations SNC2D A1.1 formulate scientific questions about observed relationships, ideas, problems, and/or issues,
make predictions, and/or formulate hypotheses to focus inquiries or research
A1.8 analyse and interpret qualitative and/or quantitative data to determine whether the evidence
supports or refutes the initial prediction or hypothesis, identifying possible sources of error,
bias, or uncertainty
A1.11 communicate ideas, plans, procedures, results, and conclusions orally, in writing, and/or
in electronic presentations, using appropriate language and a variety of formats (e.g., data
tables, laboratory reports, presentations, debates, simulations, models)
D2.1 use appropriate terminology related to climate change, including, but not limited to: albedo,
anthropogenic, atmosphere, cycles, heat sinks, and hydrosphere [C]
D3.1 describe the principal components of Earth’s climate system (e.g., the sun, oceans, and
atmosphere; the topography and configuration of land masses) and how the system works
D3.3 describe the natural greenhouse effect, explain its importance for life, and distinguish it
from the anthropogenic greenhouse effect
D3.7 describe, in general terms, the causes and effects of the anthropogenic greenhouse effect,
the depletion of stratospheric and tropospheric ozone, and the formation of ground-level
ozone and smog
SNC2P A1.1 formulate scientific questions about observed relationships, ideas, problems, and/or issues,
make predictions, and/or formulate hypotheses to focus inquiries or research
A1.8 analyse and interpret qualitative and/or quantitative data to determine whether the evidence
supports or refutes the initial prediction or hypothesis, identifying possible sources of error,
bias, or uncertainty
A1.11 communicate ideas, plans, procedures, results, and conclusions orally, in writing, and/or
in electronic presentations, using appropriate language and a variety of formats (e.g., data
tables, laboratory reports, presentations, debates, simulations, models)
D2.1 use appropriate terminology related to Earth’s dynamic climate, including, but not limited
to: anthropogenic, atmosphere, carbon footprint, carbon sink, climate, greenhouse gases,
hydrosphere, and weather [C]
D3.1 describe the principal components of Earth’s climate system (e.g., the sun, oceans, and the
atmosphere; the topography and configuration of land masses)
D3.2 describe the natural greenhouse effect, its importance for life, and the difference between it
and the anthropogenic greenhouse effect
D3.3 describe how heat is transferred and stored in both hydrospheric and atmospheric heat sinks
Introduction This demo demonstrates the greenhouse effect by comparing the air temperature of a room with
the air temperature inside a clear plastic bag containing black construction paper. The bag
models the Earth’s atmosphere and the black construction paper models Earth’s dark surface.
Materials safety goggles
2 pieces of white cardboard or plastic (approx.
3” × 5”)
hole punch or awl
2 thermometers (small enough to fit inside
plastic bag)
2 pieces of black construction paper (8.5” ×
11”)
large releasable plastic bag
heat lamp or table lamp with incandescent
bulb
flat, level white surface (at least 1 m2)
Safety Considerations The awl may be very sharp.
Procedure Wear appropriate PPE: safety goggles.
Before class begins, prepare the setup as follows:
1.
Place all materials on the white surface.
2.
Fold each white card in half lengthwise. Use the hole punch to punch through each folded
card near the centre of the folded edge, making a pair of holes.
3.
Insert one thermometer through both holes in one of the folded cards. Do the same with the
second thermometer and card.
4.
Place one sheet of black construction paper inside the plastic bag.
5.
Place one thermometer mounted in its card on the construction paper inside the plastic bag.
Position the card like a tent so that the thermometer bulb is not in contact with any surface.
Seal the bag.
6.
Place the other mounted thermometer on a second piece of black construction paper beside
the closed bag, again arranged so that the thermometer bulb is not in contact with any
surface.
7.
Place the heat lamp in such a way that it will shine equally on both thermometers (Fig.1).
Do not turn the lamp on yet.
When the class is in progress:
8.
Predict
Show the students the experimental setup and start a Think, Pair, Share session (see
Teaching Suggestions/Hints) as follows:
• Think: Which thermometer will register the larger temperature increase?
• Pair: Discuss the question with a partner.
• Share: Hold a brief class discussion on the prediction.
9.
Explain
Ask students to justify their predictions based on their knowledge of climate, the kinetic
molecular theory, and any other relevant concepts or principles.
10. Observe
Turn the heat lamp on and, over 15 min, observe and record the temperatures measured by
the two thermometers.
11. Explain
Ask students to explain the higher final temperature registered by the thermometer inside
the bag using their knowledge of climate, the kinetic molecular theory, and any other
concept or principle they find relevant.
Disposal The used materials (card, paper, and plastic) can be stored for reuse, recycled, or disposed of in
the regular garbage container. Store the thermometers and lamp for future use.
What Happens? The thermometer enclosed in the zipper bag will register a higher final temperature than the
unenclosed thermometer.
How does it work? Both pieces of construction paper absorb the same amount of light energy from the lamp and
release some of this energy as heat to the air above them. The heated air above the unenclosed
paper spreads through the room due to the movement of gas molecules. However, when enclosed
in a plastic bag, heated air cannot escape and spread through the room but is trapped to be heated
further. Thus the temperature of the air just above the enclosed paper will rise faster than that of
the air above the unenclosed paper. This demonstrates the greenhouse effect, both natural and
anthropogenic, by showing how trapping warm air maintains high temperatures. In this demo,
the bag plays the role of the greenhouse gases in the atmosphere which “trap” the heat radiating
off Earth’s surface by reflecting it back to Earth rather than allowing it to radiate out into space.
Teaching Suggestions/Hints 1.
2.
3.
4.
Using a white surface is not essential but provides a contract with the black construction
paper.
The measurements for the piece of cardboard/plastic do not need to be exact. Their purpose
is to elevate the thermometer bulb and support the bag so that the thermometer bulb is not
in contact with anything inside the bag other than air.
Allow 15 min for temperature change in Step 11. During this time discuss the importance
of the natural greenhouse effect to the maintenance of life on Earth.
Think/Pair/Share: In this learning strategy, students individually consider a concept,
question, or prediction, and then discuss their ideas with a partner. This can be followed by
small group discussions or a whole class discussion. The purpose of the strategy in this
demo is to:
• activate prior knowledge;
• think about ideas/concepts first and then share with other students for feedback;
• pace student thinking and discussion; and
• include all students in explaining and confirming predictions.
Next Steps Explore how humans have altered the natural greenhouse effect (anthropogenic greenhouse
effect) and the major ways in which this is affecting climate.
Extend the demo by turning off the lamp and tracking which thermometer registers the slower
temperature decrease as the air above the black construction paper cools off. (It will be the
enclosed one.)
Additional Resources 1.
Information about the greenhouse effect tailored to children http://climate.nasa.gov/kids/bigQuestions/greenhouseEffect/