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Ozone and Your Environment
Learn the terminology and skills used by today's scientists while focusing on one of Earth's most pressing environmental problems-Ozone in our environment.
Recently, ozone, a simple molecule made from three oxygen atoms, has been discussed with great concern in headline stories such as, "Rising Ozone Levels in LA Cause Smog Alert," and "Depletion in Ozone Layer May Lead to Cancer!" Whether it is too much or too little, the effect of human activities on the level of ozone in our environment is under close scrutiny by environmentalists, politicians, and lawmakers. The lessons in this unit well help you discover why.
Ozone can be found in two very different layers of our atmosphere, the troposphere and the stratosphere. The environmental problems related to the levels of ozone in these two atmospheric layers are very different. In the troposphere, the level of the atmosphere that we live in, ozone is a component of the air pollution commonly referred to as "smog." The amount of ozone in our troposphere is increasing because of chemicals emitted wherever natural gas, gasoline, diesel fuel, kerosene, and oil are combusted.
Nearly 90% of our Earth's ozone is found in the atmospheric layer above ours called the stratosphere. This layer extends from about 14.5 kilometers to 50 kilometers (9-31 miles) in altitude and is where airplanes fly. The ozone layer is within the stratosphere, approximately 15-40 kilometers (10-25 miles) above the Earth's surface. This ozone is important for blocking the Earth from the Sun's harmful ultraviolet (UV) rays by absorbing the UV energy and keeping the rays from penetrating to the Earth.
The environmental problems related to stratospheric ozone result from the depletion of the ozone by reactions with man-made chemical compounds called chlorofluorocarbons or CFCs. These compounds are commonly used for refrigerants, solvents, and foam-blowing agents. Depletion of ozone causes ozone holes in our atmosphere that can be seen by modern detection equipment. Currently, two major holes exist - one over the Antarctic and another over Australia. The size of these ozone holes will continue to increase unless actions are taken to decrease the level of CFCs in our atmosphere.
LESSON 1:
Ozone is News!
Concepts:
You will learn about ozone in the environment while practicing your library and Internet research skills.
Lesson:
Search for "ozone" on your favorite Internet news sites for real headlines and associated stories to read together. Have students find newspaper and magazine articles about ozone in your local library and write summaries. Start science vocabulary lists from these summaries to use in future science lessons.
LESSON 2:
Where is the Ozone!
Concepts:
You will learn about the layers of the atmosphere and the presence of ozone in the two layers closest to Earth, the troposphere and the stratosphere.
Lesson:
The Earth's atmosphere is divided into four layers that differ in their composition and temperature.
| Name of Layer |
Distance from Earth (English) |
Distance from Earth (metric) |
| Troposphere |
0 to 9 miles |
0 to 14.5 kilometers |
| Stratosphere |
9 to 31 miles |
14.5 to 50 kilometers |
| Mesosphere |
31 to 53 miles |
50 to 85 kilometers |
| Thermosphere |
53 to 372 miles |
85 to 600 kilometers |
The lowest region, the troposphere, extends from the Earth's surface up to about 14.5 kilometers (km) in altitude. Mt. Everest, the tallest mountain on the planet, is only about 9 km high. Virtually all human activities occur in the troposphere.
The next layer, the stratosphere, continues from 14.5 km to about 50 km. Most commercial airline traffic occurs in the lower part of the stratosphere. Most atmospheric ozone is concentrated in a layer in the stratosphere.
Have your students use the table and the instructions from the Ozone in the Atmosphere worksheet to draw a model of the Earth's atmosphere. Ask them to include drawings in the layers depicting the activities that influence the level of ozone in the troposphere and the stratosphere.
Additional Resources
LESSON 3:
Making and Breaking Ozone
Concepts:
You will learn about the chemical composition of ozone and the chemical reactions of its synthesis and breakdown.
Lesson:
Use the chemical equations outlined on the Making and Breaking Ozone worksheet to compare the chemical reactions of ozone in the troposphere, "low level reactions" and in the stratosphere, "high level reactions." Follow the instructions on the worksheet to model the chemical reactions using toothpicks and jellybeans. (Suggestion: you can use green and red grapes for the healthy choice!) After you have completed answering the questions on this worksheet, you can check your answers here.
Additional Resources
LESSON 4:
Ozone Pollution: Smog Alert!
Concepts:
You will learn about the effects of ozone as a pollutant when it is found in the lower atmosphere.
Lesson:
Ozone is the same molecule regardless of where it is found, but its significance varies. Stratospheric ozone is found 9 to 18 miles high where it shields us from harmful ultraviolet rays from the sun. High accumulations of ozone gas in the lower atmosphere at ground level is air pollution and can be harmful to people, animals, crops and other materials.
In this activity, developed by the Texas Natural Resource Conservation Commission, students learn about ozone pollution and perform a simple experiment to demonstrate the build-up of pollution as smog in cities and near areas of heavy industrial activity.
Additional Resources
LESSON 5:
Students Rescue Earth!
Concepts:
You will use what you learn about the effects of ozone on the environment to write a letter to your community from a scientific perspective.
Lesson:
Use the Web resources listed below to help your children learn about the environmental problems related to changes in the ozone levels in the Earth's atmosphere. Have them select one of the ozone related problems in the environment:
- Air pollution caused by increased low-level ozone concentrations
- Increases in UV penetration to Earth's surface caused by ozone depletion
Identify five specific human activities that have been shown to cause the selected problem. With this information in hand, ask your students to write letters to the editor of your local newspaper explaining what they have learned and requesting the community to take specific actions to stop pollution in the troposphere and/or ozone depletion in the stratosphere.
Make sure to submit the letters to the newspaper!
Additional Resources
LESSON 6:
Keeping the Rays OUT!
Concepts:
You will learn about experimental design and the effectiveness of substances used as sunscreens.
Lesson:
The ozone layer absorbs a portion of the radiation from the sun, preventing it from reaching the Earth's surface. Most importantly, it absorbs the portion of ultraviolet light called UVB. UVB has been linked to many harmful effects, including various types of skin cancer, cataracts, and harm to some crops, certain materials, and some forms of marine life.
Using UV sensitive Energy Beads from Sundance SolarTM, help your students design an experiment to determine the effectiveness of different sun blocking agents. Make sure that the experimental design includes the major elements of the scientific method:
Observe the elements of the system that you are investigating and identify a question that you are interested in answering.
Research information about what you plan to investigate using library books, the Internet, newspapers, and interviews with professionals.
Formulate an hypothesis (an educated guess) by predicting the answer to your question.
Design an experiment to test your hypothesis following the guidelines for correct experimental procedure:
- Select only one variable.
- Use a "control" group.
- Repeat the tests.
Gather and Record data to test the hypothesis.
Analyze the data.
Draw a conclusion.
Communicate the results to your peers.
Use the Discussion Questions from
YOU&ME&UV at the Enviro-Tackle Box to help guide your follow-up discussions.
Additional Resources
LESSON 7:
The Sky is Falling
Developed by Matthew Binder (8th grade Earth Science), Centerville Middle School, Hempfield School District, Landisville, PA.
Concepts:
You will learn about the technology scientists use to measure global ozone and learn how to access the data from the Total Ozone Mapping Spectrometer (TOMS) using the Internet.
Lesson:
The ozone layer has been a major concern in the last half of the 20th century. This activity encourages students to interact with the latest real-time ozone data on the Web. The lesson will access data from the TOMS Web page (Total Ozone Mapping Spectrometer; a satellite instrument used to measure ozone levels) to study real-time local and global ozone amounts and variations. This activity will also teach your students how to use the TOMS data for research purposes. (Excerpt from TOMS Resource Materials for Science Educators. This activity was created by the TOMS research team and acts as a tutorial for the Web site.)
Additional Resources
LESSON 8:
The Sky is Falling
Concepts:
You will get to test your knowledge of the importance of ozone in our environment by completing this online crossword puzzle.
Lesson:
Test your knowledge of ozone layer science and ozone depletion in this crossword puzzle developed by the United States Environmental Protection Agency (EPA).
Additional Resources
Article by Marie Perrie, HLN Curriculum Development
Article © Homeschool Learning Network, All Rights Reserved.
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