Teacher resources and professional development across the curriculum

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Sub Image2:Macro to Micro Structures
         
 
Workshops
1) Atoms and Molecules2) Macro to Micro Structures 3) Energetics and Dynamics 4) Theory and Practice in Chemical Systems 5) Chemical Design 6) The Chemistry of Life 7) Chemistry and the Environment
8) Chemistry at the Interface
 

Unit 7.1 Minidoc: The Hole in the Ozone Layer
The minidocumentary deals with the importance of understanding the chemistry of the environment. The causes for the formation of the hole in the ozone layer are discussed.
Video program cues: 00:30-4:354:35

Introducing ozone

"Ozone is actually a very simple molecule. It is made up of three oxygen atoms, and it has a chemical formula of O3, but it plays a very complicated role in the earth’s atmosphere. It can either be harmful or beneficial to humans, depending on where in the atmosphere it resides."

Dr. Laurie Geller
National Academy of Science

Links

  • This page has links to dozens of resources on the science of ozone depletion. Some of the sources are intended for a technical audience, but there is more than enough here for students and teachers.
  • This is NASA’s Total Ozone Mapping Spectrometer (TOMS) home page with a link to visual images of the ozone hole from 2000 and 2001 compared, as well as other current ozone images and data.

Reading
Pirjola, L. (2000)' Local Atmospheric Chemistry and Ozone Model (LACOM), 'Journal of Chemical Education, Vol. 77, No. 12, pp: 1650-1653.

CFCs in the atmosphere

"When they created CFCs, they purposely made them very strong, because that made them very useful for industrial processes. But that also made them different in that they basically survive in the lower atmosphere for quite a long time, and unlike most molecules, which get washed out, they hang out there for a long time and eventually make their way up to the stratosphere. When CFC molecules get to the upper atmosphere, they get exposed to strong UV radiation, that has enough energy to break the chemical bonds of the molecule, and finally the CFC molecules meet their destruction in the atmosphere. The problem is that what you are left with is a free chlorine atom, which is very reactive. The basic reaction is between chlorine and ozone, and in the next step a lone chlorine atom is regenerated; such that one chlorine atom may destroy up to 100,000 ozone molecules."

Dr. Laurie Geller
National Academy of Science


Link

  • A glossary of ozone depletion terms from EPA.


The hole in the ozone Layer

"There have been many efforts to design alternatives [to the repair of the ozone hole]. We have a whole group working on looking for compounds which decompose before they reach the ozone layer."

Dr. Laurie Geller
National Academy of Science

"There have been lots of ideas about how to fix the chemistry of what is going on in the atmosphere. The only way that we know that will work and is safe, is to stop releasing these CFCs into the atmosphere."

Dr. Carlos Gonzalez
Carnegie Mellon University

Link

  • Complete background, including the chemistry, on ozone depletion, from the University of Cambridge. Includes illustrations, a glossary and links to other sources. Ideal for student use.

Reading
Zurer, P. (1999)' Slow Road to Ozone Recovery, 'Chemical and Engineering News, Vol. 77, No. 17, pp: 8-9.

Proceed to Unit 7.2 arrow
 
 

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