Greenhouse Gas in a Bottle Demonstration
Topic: Greenhouse Gases
Course Type: All levels, any size class, face-to-face or online. For more advanced classes, consider including some of the supplementary extensions
This activity teaches Climate Literacy Essential Principle 2: Climate is regulated by complex interactions among components of the Earth system
This activity teaches Concept C - Greenhouse Effect. The amount of solar energy absorbed or radiated by Earth is modulated by the atmosphere and depends on its composition. Greenhouse gases— such as water vapor, carbon dioxide, and methane— occur naturally in small amounts and absorb and release heat energy more efficiently than abundant atmospheric gases like nitrogen and oxygen. Small increases in carbon dioxide concentration have a large effect on the climate system.
Students should be able to do the following:
- EXPLAIN the effect that increased carbon dioxide has on atmospheric temperature.
- CONTRAST the role GHGs play compared to main atmospheric constituents.
This is a simple demonstration that is quick and easy to setup and provides dramatic evidence of the effect on temperature of an atmosphere with increased carbon dioxide.
This could easily be done by an instructor at the start of a class session with results evident 40 minutes later. Ideally, use digital thermometer probes, such as Vernier Go!Temp, and then display the results to entire class in real time using an overhead projector.
Students could also conduct this demonstration in smaller groups. Once set up, it runs by itself with no external attention needed.
This demonstration allows for a number of interesting variations to address several related greenhouse questions and give students practice in thinking scientifically. Possible supplementary extensions include:
1. Measure the temperature in the two bottles before heating but after adding seltzer, to eliminate the possibility that adding seltzer adds heat somehow.
2. Add seltzer only after the two bottles have been heated and reached thermal equilibrium.
3. Measure the temperature in the two bottles before heating; remove the thermometers; heat the two bottles for a while; reinsert the thermometers. (This allows the thermometers to measure temperature by conduction "only", instead of reaching a combined radiative and conductive equilibrium, which provides a more accurate estimate of how much the temperature of the gases in the bottles go up.)
4. Paint half of each bottles black and shine the light on the black side. That way, the radiation passing entering the gas is primarily infrared radiation emitted by the black paint and heated side of bottle instead of a combination of visible, near infrared, and longwave infrared. This would also shield the thermometers from direct visible light, but not from a radiative source at a higher temperature. This idea is designed to try to get at one of the desired points of the demo, that carbon dioxide is transparent to visible light but not to longwave IR, an important property for understanding the greenhouse gas effect.
5. Measure the pressure in the bottle after adding the seltzer tablets to try to get a sense of how much CO2 has been added. Ask students to relate this to current, past, and projected CO2 concentrations in the earth's atmosphere, as well as on Venus.
6. Measure the amount of water vapor in each bottle, before and after they are heated, to try to get a sense of the feedback response.
7. Measure the amount of carbon dioxide in the bottle with a CO2 sensor and then compare it to the amount in earth's atmosphere.
8. Measure the pH of the water with and without the dissolved tablets and then discuss ocean acidification and CO2.9. Get students to think about alternative explanations for the difference in heating and design alternative versions of the demo to try to eliminate them (or confirm them, in the case of water vapor feedback, say).
Teaching MaterialsInstructions - GHG Demo Instructions (Microsoft Word 125kB Jun15 11)
YouTube videoThe Greenhouse Gas Demo
This demonstration is best used in conjunction with other activities and class discussion. Assessment Ideas (Microsoft Word 71kB Jun20 11)
Connections to other Activities
This activity is one of a suite of five activities designed to address the concepts that address how the greenhouse effect influences global temperature (Principle 2, Concept C) which can be used individually or combined as desired.
This activity is adapted from the NSW JetStream Online School for Weather: http://www.srh.noaa.gov/jetstream/atmos/ll_gas.htm
Windows to the Universe: http://www.windows2universe.org/earth/climate/greenhouse_effect_gases.html
Vernier Go!Temp temperature probe - http://www.vernier.com/go/gotemp.html
Vernier CO2 sensor - http://www.vernier.com/probes/co2-bta.html
Vernier pH sensor - http://www.vernier.com/probes/ph-bta.html
Vernier gas pressure sensor - http://www.vernier.com/probes/gps-bta.html
More on this topic from CLEAN
How to teach with this principle from the CLEAN site
See CLEAN reviewed activities for teaching about Greenhouse Effect