The greenhouse effect itself can be understood at many levels, from the earth’s atmosphere to a 2-liter plastic bottle. In this lesson, students will learn how different wavelengths react in regards to the greenhouse effect by participating in a brief experiment with a 2-liter pop bottle.
Goals:
- Understand how heat stays within the earth’s atmosphere in the analogy of a greenhouse. (i.e. the greenhouse effect)
- Understand how greenhouse gases interact with infrared radiation
- Understand how different wavelengths (visible, UV, infrared) are affected when sunlight enters a container (i.e. earth, car, greenhouse, 2 liter bottle).
- Understand and apply knowledge of interactions of energy and matter.
Background Information/Additional Resources:
- Diagrams and explanations of the Greenhouse Effect
- Easy walk through of greenhouse effect
- Video: “The Greenhouse Gas Demo”
- “Carbon Dioxide and Climate”
The Greenhouse Effect Activity
Have students conduct a short experiment to demonstrate the greenhouse effect using 2-liter bottles. See the “Experiment to Demonstrate the Effects of Greenhouse Gases”
Potential Student Question and Answers
Q: Does UV radiation enter a car through the glass? Can I get sunburned through a car window?
A: No, shorter wavelengths of ultraviolet light are largely blocked by glass since they have greater quantum energies. These quantum energies have absorption mechanisms in the glass. So, although you may be exposed to sun, you will not be sunburned.
Q: When do the visible light rays turn into long-wave infrared radiation?
A: Visible light is transmitted through the glass initially, but after these visible light rays heat up objects, these objects will re-radiate long-wave infrared waves.
Q: Are greenhouse gas levels rising or decreasing?
A1: “Looking specifically at CO2, the Mauna Loa Observatory in Hawaii shows that CO2 levels in 1958 were 315 parts per million (ppm), and currently the atmospheric level of CO2 is 380 ppm.”
A2: Also, the Intergovernmental Panel on Climate Change produced a report stating that methane, CO2, and nitrous oxide all have increased significantly through the past 1000 years. However, the majority of this increase has happened in the past 200 years.
Q: What is the most prominent greenhouse gas?
A: Below are the five most abundant greenhouse gases, listed in order from most to least abundant:
- Water Vapor
- CO2
- Methane
- Nitrous Oxide
- Ozone
Q: What else besides greenhouse gases can prohibit solar radiation from leaving the earth?
A: Of the re-radiated infrared waves that the earth emit, 3% is absorbed by clouds, 16% is absorbed by the atmosphere, 6% is radiated directly to space, and 64% is radiated from the atmosphere/clouds back into space.
Q: What is the biggest human impact on global warming?
A: There is no factual answer to this question. However, CO2 emission levels have increased at an exponential rate from the combustion of fossil fuels. Before the industrial revolution, our atmospheric CO2 levels were 270 ppm, compared to the current levels of 380 ppm.
Focus the Classroom 