Session #5: Creating an Earth System II

Overview:

Following a review of El Nino, discussions focused on additional examples of the integration of the biological, chemical, and physical processes within the Earth's system. These included the natural occurrence of mass extinctions and the ways that humans have influenced the system, focusing on the ozone layer, the greenhouse effect, and global warming.

Jump to: Mass Extinctions | The Electromagnetic Spectrum | Learning About the Ozone | Greenhouse Effect and Global Warming | Additional Resources

Mass Extinctions

Of all the species that have ever lived, 99% are now extinct; therefore extinctions are quite common. However, there have been at least six times during Earth's history when a significant percentage of the existing organisms have gone extinct. Such events are referred to as mass extinctions and are caused by a global change of the environment and the failure of species to adapt at a rate equal to or greater than the rate of that change. Perhaps one of the most famous mass extinction occurred at the end of the Cretaceous, during which the dominant land vertebrates, in particular the dinosaurs, went extinct. Though the exact cause of this extinction is not certain, the occurrence of a large asteroid impact certainly played a significant role.

Discussion: Examining the potential effects of an asteroid impact

The Electromagnetic Spectrum

Before beginning a discussion of the atmosphere, ozone and greenhouse gases, teachers reviewed the electromagnetic spectrum.

Discussion: The Electromagnetic Spectrum

Learning About the Ozone

Following a review of the divisions of the Earth's atmosphere, teachers learned about the importance of the ozone layer.

Discussion: Learning about the Ozone

Activity: Whole Body Ozone Chemistry
In this activity, students play the roles of various atoms and molecules to help them better understand the formation and destruction of ozone in the stratosphere.

Activity: The Ultraviolet Project Chemistry
In this activity, students use ultraviolet sensitive beads to learn about the effects of ultraviolet rays produced by the Sun.

Greenhouse Effect and Global Warming

Earth is habitable because of the 'greenhouse effect' but an enhanced greenhouse effect can be associated with the trend in global warming.

Discussion: Greenhouse Effect and Global Warming

Activity: The Greenhouse Effect in a Jar
This is an imperfect analogy of the Green House Effect but a good model of a real greenhouse.

Activity: What Do Concentrations Mean?
In this activity, students explore how many dilutions it takes to achieve a parts-per-million dilution of a common substance (food coloring).
Please note: the table of gas and PPM illustrated within the teacher resource is out of date. The more appropriate PPM for CO₂ is 370.

Activity: Human Activity and Climate Change
In this activity, students examine graphs of GHG (greenhouse gases) emissions and the increases associated with human activity.

Activity: Introduction - Greenhouse Gases
Students compare the greenhouse emissions of different countries to the population of each country.

Additional Resources

Educational Resources of the US Environmental Protection Agency

Greenhouse Effect and Global Warming
U.S. EPA document (pdf file): Download from course Web site (if you can't wait, go to http://yosemite.epa.gov/oar/globalwarming.nsf/UniqueKeyLookup/SHSU5BMSCH/$File/all_science.pdf

LEARN: Atmospheric Science Explorers
A website to increase middle school science teacher knowledge of and interest in the atmospheric sciences.

Global Warming & The Greenhouse Effect
A GEMS guide

Other Electromagnetic Spectrum and Ozone links

Updated January 5, 2003