Environmental Hazard VI: Depletion of the Ozone Layer and Its Effect

Subject: Basic Science

Class: JSS 3

Term: First Term

Week: 10

Age: 12 – 14 years

Topic: Environmental Hazard – Depletion of the Ozone Layer

Sub-Topic: Causes, Effects, and Control of Ozone Layer Depletion

Duration: 40 minutes

Behavioural Objectives

By the end of the lesson, students should be able to:

1. Describe the ozone layer and its location in the atmosphere.
2. Explain the importance of the ozone layer in protecting life on Earth.
3. Discuss the causes and effects of ozone layer depletion, such as global warming and flooding.
4. List control measures, including the regulation of chlorofluorocarbons (CFCs).
5. Suggest ways to reduce human activities that worsen ozone depletion.

Keywords

• Ozone Layer: A protective layer of gas in the atmosphere that absorbs ultraviolet (UV) radiation.
• CFCs: Chemicals that deplete the ozone layer, found in aerosols and refrigerators.
• Greenhouse Effect: Trapping of heat by gases, leading to global warming.
• Global Warming: Rise in Earth’s temperature due to increased greenhouse gases.
• Ultraviolet Rays: Harmful rays from the sun blocked by the ozone layer.

Set Induction

The teacher begins by asking:

• “Have you ever felt the sun getting hotter each year? What do you think is responsible for this?”
  This question stimulates students to think about the link between environmental changes and human activities.

Entry Behaviour

Students may have heard of climate change or global warming through the news or previous lessons on environmental hazards.

Learning Resources and Materials

• Posters showing the structure of the atmosphere and the location of the ozone layer.
• Videos demonstrating the effects of UV radiation on the environment.
• Charts explaining the greenhouse effect.

Building Background/Connection to Prior Knowledge

The teacher connects this topic with previous lessons on bush burning and deforestation, showing how they contribute to environmental degradation.

Embedded Core Skills

• Environmental Literacy: Understanding the causes and effects of ozone depletion.
• Critical Thinking: Evaluating ways to reduce ozone-depleting activities.
• Problem Solving: Proposing sustainable environmental practices.

Instructional Materials

• Lagos State Scheme of Work
• Basic Science textbooks
• Infographics on CFC alternatives and sustainable practices

Content

1. Description of the Ozone Layer and Its Location

• The ozone layer is a layer of ozone (O3) gas located in the stratosphere of the Earth’s atmosphere.
• It serves as a protective shield that absorbs most of the sun’s harmful ultraviolet (UV) rays.

2. Importance of the Ozone Layer

1. Protection from UV Rays: Prevents harmful radiation from reaching the Earth’s surface.
2. Preserves Ecosystems: Protects plants, animals, and humans from UV-induced damage.
3. Prevents Skin Cancer: Shields humans from harmful UV rays that cause skin cancer.
4. Maintains Climate Balance: Helps regulate Earth’s temperature.

3. Causes of Ozone Layer Depletion

1. Release of CFCs: Found in air conditioners, refrigerators, and aerosol sprays.
2. Bush Burning: Increases gases that contribute to atmospheric depletion.
3. Deforestation: Reduces trees that absorb harmful gases.
4. Industrial Emissions: Release of chemicals that destroy ozone molecules.

4. Effects of Ozone Layer Depletion

1. Global Warming: Increase in Earth’s temperature due to greenhouse gases.
2. Melting of Polar Ice: Causes rising sea levels, leading to flooding.
3. Greenhouse Effect: Traps heat in the atmosphere, worsening climate change.
4. Health Risks: Increases risk of skin cancer and cataracts from UV exposure.

5. Control Measures

1. Regulate Use of CFCs: Replace harmful chemicals with eco-friendly alternatives.
2. Reduce Bush Burning: Encourage proper waste disposal methods.
3. Control Household Activities: Use eco-friendly appliances and aerosols.
4. Afforestation: Plant trees to absorb carbon dioxide and improve air quality.
5. Raise Environmental Awareness: Educate people on sustainable practices.

6. Regulations on CFCs

• Many countries, including Nigeria, have adopted CFC bans under the Montreal Protocol, an international treaty to protect the ozone layer.
• Encouraging industries to adopt environmentally safe alternatives like hydrofluorocarbons (HFCs).

Board Summary

• Ozone Layer: Protective layer in the atmosphere that absorbs UV rays.
• Causes of Depletion: CFCs, bush burning, industrial emissions.
• Effects: Global warming, health risks, flooding.
• Control Measures: Regulate CFCs, reduce bush burning, afforestation.

Class Activity Discussion (FAQs)

1. What is the ozone layer?
   • It is a layer of gas in the stratosphere that protects Earth from UV rays.
2. Why is the ozone layer important?
   • It shields us from harmful ultraviolet radiation.
3. What are CFCs?
   • Chlorofluorocarbons, chemicals that destroy the ozone layer.
4. How does bush burning affect the ozone layer?
   • It releases gases that deplete the ozone layer.
5. What is global warming?
   • An increase in Earth’s temperature due to greenhouse gases.
6. How does the Montreal Protocol help?
   • It regulates the use of ozone-depleting substances.
7. What happens when polar ice melts?
   • Sea levels rise, leading to floods.
8. What are alternatives to CFCs?
   • Hydrofluorocarbons (HFCs) and other eco-friendly chemicals.
9. How can we reduce ozone depletion?
   • By using CFC-free products and planting trees.
10. Why should we avoid burning waste?

• It releases harmful gases into the atmosphere.

Teacher’s Activities

1. Use charts to explain the structure and function of the ozone layer.
2. Discuss the effects of ozone depletion using real-life examples.
3. Engage students in brainstorming solutions to reduce CFC use.

Learners’ Activities

1. Identify household products that contain CFCs.
2. Discuss the impact of global warming on Nigeria.
3. Work in groups to propose environmental-friendly practices.

Evaluation: 15 Fill-in-the-Blank Questions

1. __________ is a layer of gas that protects Earth from UV rays.
   a) Ozone Layer
   b) Greenhouse Gas
   c) Carbon Dioxide
   d) Stratosphere
2. __________ are chemicals that destroy the ozone layer.
   a) CFCs
   b) HFCs
   c) Oxygen
   d) Nitrogen
3. The ozone layer is located in the __________.
   a) stratosphere
   b) troposphere
   c) mesosphere
   d) thermosphere
4. __________ causes global warming.
   a) Greenhouse gases
   b) Oxygen
   c) Nitrogen
   d) Ozone
5. __________ is an international treaty to protect the ozone layer.
   a) Montreal Protocol
   b) Kyoto Protocol
   c) Paris Agreement
   d) Stockholm Treaty
6. __________ refers to the rise in global temperature due to trapped heat.
   a) Global warming
   b) Deforestation
   c) Pollution
   d) Ice melting
7. CFCs are commonly found in __________.
   a) refrigerators
   b) clothing
   c) paper
   d) bricks
8. __________ refers to planting trees to reduce environmental degradation.
   a) Afforestation
   b) Deforestation
   c) Grazing
   d) Burning
9. Bush burning contributes to __________ depletion.
   a) ozone
   b) oxygen
   c) nitrogen
   d) carbon
10. __________ occurs when polar ice melts.
    a) Flooding
    b) Earthquake
    c) Drought
    d) Landslide

Conclusion

The teacher concludes by emphasizing the importance of protecting the ozone layer and adopting sustainable practices to prevent environmental hazards.

Captivating Title

Protecting the Ozone Layer: Causes, Effects, and Solutions

Focus Keyphrase

Ozone layer depletion and climate impact

SEO Title

Ozone Depletion: Causes, Effects, and Prevention | JSS 3 Science

Slug

ozone-depletion-environmental-hazard-jss3

Meta Description

Learn about ozone layer depletion, its causes, effects, and prevention strategies in this JSS 3 Basic Science lesson. Protect the planet today!