Show
Blackbody radiation and greenhouse effect Type: Integrated unit with
five separate interactive computer-based activities. Students will use graphical tools to understand blackbody radiation, identify different spectrum ranges, learn about the interaction of atmospheric gases with radiation of different wavelengths, and recognize the relationship between greenhouse gases and global average temperature. This unit provides a foundational understanding of the greenhouse effect and its role in controlling Earth’s temperature. Teaching NotesGrade Level: High school, but could be adapted to 8th grade. Learning Goals: After completing this unit, users will be able to:
Rationale: This unit helps students understand the basics of the greenhouse effect and the relationship between greenhouse gas concentrations and global temperatures. Students will be able to understand terminology related to solar and terrestrial radiation. Students will be able to recognize different greenhouse gases and the mechanism by which they interaction with terrestrial radiation. Students will use a variety of web based visualization tools and Excel to plot data obtained from these tools. Key Concepts and Vocabulary
Background InformationTo understand the role of greenhouse gases in global climate change, it is important to understand the basics of blackbody radiation and the interaction of greenhouse gases with Earth’s long-wave radiation. All bodies emit energy in the form of electromagnetic (EM) radiation. The sun’s energy reaches Earth in the form of light – a form of EM radiation (Figure 1). We feel the warmth from a fireplace even with a glass barrier because of EM radiation. The warm coil on the stove glows because it emits EM radiation and the coil’s heat is felt at a distance because of EM radiation. Heat and light are both forms of electromagnetic radiation. Other forms of electromagnetic radiation include: x-rays, gamma-rays, and radio waves. The different forms of EM radiation correspond to different energies and wavelength ranges as illustrated in Figure 1. A black body is a body that absorbs all radiation that it receives and emits radiation in all wavelengths. The net intensity of the radiation emitted by a blackbody is dependent on its temperature (intensity is proportional to T4), with hotter bodies emitting greater amounts of radiation. While blackbodies emit radiation over all wavelengths, a significant fraction of their emitted energy is concentrated in a limited range of wavelengths. The wavelength corresponding to the peak intensity of emission decreases with increasing temperature. Sun and Earth can both be considered black bodies in analyzing their radiative properties. The EM radiation from Sun is primarily in short or visible wavelengths (0.4 – 0.7 mm) corresponding to the Sun’s high temperature (~ 5777 K), while the EM radiation associated with Earth’s emission to space is primarily in the infrared wavelength range (1-10 mm), corresponding to its cooler temperature (~ 298 K; Figure 3). As Earth’s temperature is largely in equilibrium, the incoming short-wave radiation should be balanced by the outdoing long-wave radiation. Not all the long-wave radiation emitted by Earth escapes to space. Some gases in the atmosphere can absorb Earth’s long-wave radiation and heat up the surrounding air by collisions with the neighboring molecules. The heated layer can then radiate energy back to Earth’s surface. This effect of trapping the outgoing long-wave radiation and warming up Earth’s atmosphere and surface is referred to as the Greenhouse effect and the gases that absorb long-wave radiation and create the greenhouse effect are called Greenhouse gases (GHGs). Without GHGs, Earth’s temperature would be too cold for humans (~ 0oF rather than 60oF that we have currently). Thus, GHGs are essentially for maintaining life on Earth. The most abundant GHG in the atmosphere is water vapor. The concentration of water vapor in the atmosphere is a consequence of Earth’s temperature, existing in equilibrium with liquid water and ice on Earth’s surface. The atmospheric water vapor concentration is not directly controlled by anthropogenic emissions. Some of the important greenhouse gases with anthropogenic sources are: Carbon dioxide (CO2), Methane, (CH4) and Nitrous Oxide (N2O). The concentrations of these gases can critically control the extent of Earth’s long-wave radiation trapped in the atmosphere. Anthropogenic sources of these gases are primarily from the combustion of fossil fuels. The concentrations of greenhouse gases have steadily increased since the Industrial Revolution. A corresponding increase in the average global temperatures has also been observed. Instructional StrategiesThis unit has multiple parts that are best done with students in pairs or groups of 3. The grouping will allow students to support each other and discuss their findings as they explore the different tools. Students will use the visualization tools to determine the wavelengths associated with different electromagnetic waves and determine the primary emission wavelengths for Sun and Earth and understand the role of greenhouse gases in trapping long-wave radiation and relation between global GHG concentrations and global temperature. The outcomes of these activities are:
ImplementationAnticipatory Set – Assuming students have already been introduced to the general climate change vocabulary (e.g., GHGs, GHG emissions, Carbon footprint), begin the unit by having students explore what Earth’s source of energy is and how it is received. What differences in temperatures have the students noticed between cloudy and clear nights in winter? Once the students understand that Sun is the source of energy and that “heat” from Earth can escape to space, proceed to unit. General Procedure
By the end of the unit, the students should recognize the importance of the role of GHGs in keeping Earth warm enough for humans to survive and understand that the greenhouse effect is the result of absorption of long-wave radiation from Earth’s surface by some atmospheric gases. The students should also be able to list a few major greenhouse gases. Context and StandardsLearning ConceptsThis module lend itself to upper level science courses. In Physics, wave lengths and the concept of electromagnetic radiation may be discussed in greater detail. It would also be appropriate to incorporate these activities with a chemistry lecture related to chemical bonds, photochemical reactions, etc. Data graphing and graph interpretation could all be integrated into mathematics class as a real-world application of technology skills. Science StandardsThe following New York State, Mathematics, Science and Technology (MST) Standards are supported by this unit: (http://www.p12.nysed.gov/ciai/standards.html) Analysis, Inquiry, and Design Students will use mathematical analysis, scientific inquiry, and engineering designs, as appropriate, to pose questions, seek answers, and develop solutions.
The Physical Setting Students will understand and apply scientific concepts, principles, and theories pertaining to the physical setting and living environment and recognize the historical development of ideas in science.
Interconnectedness: Common Themes Students will understand the relationships and common themes that connect mathematics, science, and technology and apply the themes to these and other areas of learning.
Method Part 1: Electromagnetic spectrum
Part 2: Blackbody radiation
Part 3a: Greenhouse gas interactions with EM radiation (middle school students)
Part 3b: Greenhouse gas interaction with EM radiation (high school students)
Part 4: Greenhouse effect
Case Study: Greenhouse EffectUsing the EM spectrum applet, answer the following questions:
Blackbody Spectrum Worksheet
Using the applet answer the following questions:
Atmospheric Gases and EM Radiation Worksheet Directions:
Using the Atmospheric gases and EM radiation applet, answer the following questions:
Greenhouse Gases and EM Radiation Worksheet Directions:
Using the Greehouse Gases and EM Radiation applet, answer the following questions:
Greenhouse Gases and Earth's Temperature Worksheet Directions:
Using the greenhouse gases and Earth's temperature applet, answer the following questions:
What is relationship between greenhouse and global warming?“Global warming” refers to the rise in global temperatures due mainly to the increasing concentrations of greenhouse gases in the atmosphere. “Climate change” refers to the increasing changes in the measures of climate over a long period of time – including precipitation, temperature, and wind patterns.
What is the relationship between the greenhouse effect and global warming quizlet?What is the Greenhouse Effect and Global warming? The Greenhouse effect is when the heat goes up into space, Greenhouse Gases, block the heat going into space, and it goes back to earth. Global Warming is when the earth being overheated by Fossil fuels and Greenhouse gases causing Greenhouse effect.
What is the connection between the greenhouse effect and global warming Brainly?Explanation: The greenhouse effect is a natural process traps heat in the atmosphere - global warming tends to be when additional greenhouse gases are released into the atmosphere and this causes a warming event.
|