Basic Science and Technology - Junior Secondary 3 - Environmental hazard VI - Depletion of the ozone layer

Environmental hazard VI - Depletion of the ozone layer

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TERM: 1ST TERM

WEEK: 10

CLASS: Junior Secondary School 3

AGE: 14 years

DURATION: 40 minutes each for 2 periods

DATE:

SUBJECT: Basic Science

TOPIC: Environmental hazard VI - depletion of the ozone layer

SPECIFIC OBJECTIVES: At the end of the lesson, the learners should be able to

  1. ) Outline the hazard of the depletion of the ozone layer
  2. ) State the control measures against the ozone layer depletion

INSTRUCTIONAL TECHNIQUES: Identification, explanation, questions and answers, demonstration, story-telling, videos from source

INSTRUCTIONAL MATERIALS: Recommended Basic Science textbooks for Junior Secondary School 3

INSTRUCTIONAL PROCEDURES: PERIOD 1-2:

PRESENTATION

TEACHER’S ACTIVITY

PUPIL’S ACTIVITY

STEP 1

Review

The teacher revises the previous lesson.

Learners pay attention

STEP 2

Introduction

He outlines the hazards of the depletion of the ozone layer

Learners pay attention and participate

STEP 3

Explanation

He states and explains the control measures against the ozone layer depletion

Learners pay attention and participate

STEP 4

NOTE TAKING

The teacher writes a short note on the board for the learners to copy

The learners copy the note from the board

 

NOTE

ENVIRONMENTAL HAZARD VI- DEPLETION OF THE OZONE LAYER

Hazards of the Depletion of the Ozone Layer:

The depletion of the ozone layer can lead to several serious environmental and health hazards, including:

  • Increased UV Radiation Exposure: The ozone layer acts as a shield that absorbs and blocks most of the Sun's harmful ultraviolet (UV) radiation, particularly UV-B rays. A depleted ozone layer allows higher levels of UV-B radiation to reach the Earth's surface, increasing the risk of skin cancer, cataracts, and other eye diseases in humans.
  • Immune System Suppression: Prolonged exposure to increased UV radiation can weaken the immune system, making individuals more susceptible to infections and diseases.
  • Environmental Damage: Increased UV radiation can harm marine ecosystems, particularly phytoplankton, which forms the base of the aquatic food chain. This can lead to disruptions in the food chain, affecting fish populations and other marine life.
  • Crop Damage: UV radiation can also damage crops and vegetation, reducing agricultural productivity. This may lead to food shortages and economic losses for farmers.
  • Decreased Biodiversity: UV-B radiation can negatively affect various organisms, including amphibians, insects, and marine life, threatening biodiversity and the balance of ecosystems.

 

Control Measures Against Ozone Layer Depletion:

Several actions have been taken globally to mitigate the depletion of the ozone layer, including:

  • The Montreal Protocol: This international treaty, adopted in 1987, aims to phase out the production and consumption of ozone-depleting substances (ODS) like chlorofluorocarbons (CFCs), halons, and other chemicals. The treaty has been successful in reducing the use of harmful substances and is considered one of the most effective environmental agreements.
  • Phasing Out Ozone-Depleting Chemicals: Governments and industries worldwide have taken steps to ban or restrict the use of chemicals that damage the ozone layer, including CFCs, halons, and other ODS. Many of these chemicals were once used in refrigeration, air conditioning, solvents, and foam-blowing agents.
  • Promoting Alternatives to ODS: The development and adoption of safer alternatives, such as hydrofluorocarbons (HFCs), hydrochlorofluorocarbons (HCFCs), and natural refrigerants, has helped reduce the impact on the ozone layer.
  • Raising Awareness and Education: Governments, environmental organizations, and educational institutions have launched campaigns to educate the public about the importance of protecting the ozone layer. Awareness helps reduce the use of products containing ODS and encourages environmentally friendly practices.
  • Research and Monitoring: Ongoing scientific research and monitoring of the ozone layer help track its recovery progress and understand the effects of depletion. Satellite data and ground-based stations play an essential role in monitoring the ozone layer and ensuring the effectiveness of control measures.

 

EVALUATION:

  1. What are the main hazards associated with the depletion of the ozone layer?
  2. How does the depletion of the ozone layer affect human health and the environment?
  3. What international agreement was established to control the depletion of the ozone layer, and what are its key objectives?
  4. What are some of the measures that have been taken to control the use of ozone-depleting substances (ODS)?
  5. How can individuals contribute to the protection of the ozone layer in their daily lives?

CLASSWORK: As in evaluation

CONCLUSION: The teacher marks their books and commends them positively