Lesson Notes By Weeks and Term - Senior Secondary 1

The Earth Structure 2

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TERM – 1ST TERM

WEEK EIGHT

Class: Senior Secondary School 1

Age: 15 years

Duration: 40 minutes of 5 periods each

Date:

Subject: Geography

Topic: The Earth Structure 2

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

  1. Explain the interior zones of the earth.
  2. Analyse the impact of human activities on the crust.

INSTRUCTIONAL TECHNIQUES: Identification, explanation, questions and answers,

demonstration, videos from source

INSTRUCTIONAL MATERIALS: Videos, loud speaker, textbook, pictures

INSTRUCTIONAL PROCEDURES

PERIOD 1-2

PRESENTATION

TEACHER’S ACTIVITY

STUDENT’S

ACTIVITY

STEP 1

INTRODUCTION

The teacher introduces and explain the interior zones of the earth

Students as a class, describe the interior zones of the earth crust.

STEP 2

EXPLANATION

Teacher explain the impacts of human activities on the crust

Students in small groups analyse the impact of human activities on the crust.

STEP 3

NOTE TAKING

The teacher writes a summarized note on the board

 

The students

copy the note in

their books

 

NOTE

THE EARTH'S STRUCTURE2

The Earth is divided into four interior zones

  1. Crust: The Earth's outermost layer, the crust, is relatively thin and rigid. It primarily consists of solid rocks, with the continental crust being thicker and less dense than the oceanic crust.

The crust is where all terrestrial life exists. It contains Earth's landforms, oceans, and supports ecosystems. It is also crucial for human activities such as agriculture, construction, and resource extraction.

  1. Mantle: Below the crust lies the mantle, extending to a depth of about 2,900 kilometers (1,800 miles). Composed mainly of solid rock that can deform and flow slowly over geological timescales.

The mantle plays a vital role in plate tectonics. Convection currents in the mantle drive the movement of tectonic plates, leading to earthquakes, volcanic activity, and the formation of mountain ranges. It influences the Earth's surface and geological features.

  1. Outer Core: Beneath the mantle is the outer core, starting at a depth of about 2,900 kilometers. Mostly composed of molten iron and nickel. The movement of these metals generates Earth's magnetic field through the geodynamo process.

The outer core's movement of molten iron and nickel generates Earth's magnetic field through the geodynamo process. This magnetic field shields the planet from solar winds and cosmic radiation, making it crucial for the preservation of the atmosphere and habitability.

  1. Inner Core: At the Earth's center lies the inner core. Despite intense pressure, the inner core is solid and primarily composed of iron and nickel. The high pressure keeps these metals in a solid state despite their high temperatures.

The solid inner core contributes to the Earth's overall structure and stability. Understanding its properties helps scientists gain insights into the Earth's composition, heat distribution, and the behavior of materials under extreme pressure and temperature conditions.

Impacts of human activities on the Earth's crust

Human activities can have various impacts on the Earth's crust, leading to both localized and global consequences. These impacts include:

  1. Mining and Extraction: Extensive mining for minerals, metals, and fossil fuels can lead to the disruption of the Earth's crust. This includes habitat destruction, soil erosion, and changes in topography.
  2. Deforestation and Land Use Changes: Clearing large areas of forests for agriculture or urban development alters the balance of the Earth's crust. It can contribute to soil erosion, destabilize slopes, and increase the risk of landslides.
  3. Urbanization: The construction of cities and infrastructure involves significant modifications to the Earth's crust. This can lead to land subsidence, changes in groundwater flow, and increased vulnerability to geological hazards.
  4. Climate Change: Human-induced climate change, driven by activities like burning fossil fuels, affects the Earth's crust indirectly. Changes in temperature and sea levels can influence geological processes, including glacial erosion and isostatic rebound.
  5. Waste Disposal: Improper disposal of waste, including hazardous materials, can lead to soil and groundwater contamination. This contamination can have long-lasting effects on the Earth's crust and ecosystems.
  6. Groundwater Extraction: Excessive withdrawal of groundwater for agriculture and urban water supply can lead to land subsidence, where the land sinks due to the depletion of underground water reservoirs.

EVALUATION: 1. Identify the four interior zones of the earth

  1. Give 4 impacts of human activities on the Earth crust.

CLASSWORK: As in evaluation

CONCLUSION: The teacher commends the students positively