Lesson Notes By Weeks and Term - Senior Secondary 2

TERM – 1^ST TERM

WEEK TWO

Class: Senior Secondary School 2

Age: 16 years

Duration: 40 minutes of 5 periods each

Date:

Subject: Geography

Topic: ACTION OF WIND

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

1. Mention examples, types and characteristics of deserts
2. Explain the processes of wind erosion
3.  Describe the features of wind erosion and deposition.
4. Analyse man survival strategies in desert environments.

INSTRUCTIONAL TECHNIQUES: Identification, explanation, questions and answers,

demonstration, videos from source

INSTRUCTIONAL MATERIALS: Videos, loud speaker, textbook, pictures

INSTRUCTIONAL PROCEDURES

PERIOD 1-2

NOTE

ACTION OF WIND

A desert is a biome characterized by arid or extremely dry conditions, typically receiving very little precipitation.

Types of Deserts

1. Hot Desert: A hot desert is a biome characterized by high temperatures, typically exceeding 100°F (38°C) during the day, and low precipitation, often less than 250mm annually. Examples include the Sahara and the Arabian Desert.
2. Cold Desert: A cold desert is a biome with low temperatures and sparse vegetation, experiencing harsh winters. Precipitation is often in the form of snow, and annual rainfall is generally low. Examples include the Gobi Desert and the Great Basin Desert.
3. Coastal Desert: A coastal desert is a biome located along coastlines, characterized by arid conditions and limited rainfall. Despite proximity to the ocean, these deserts often experience dry climates due to rain shadows created by coastal mountain ranges. Examples include the Atacama Desert in South America and the Namib Desert in southwestern Africa.
4. Rain Shadow Desert: A rain shadow desert is a type of desert formed on the leeward side of a mountain range. When moist air is forced to rise over the windward side of a mountain, it cools and releases precipitation. The descending air on the leeward side, however, becomes warmer and absorbs moisture, creating dry conditions and forming a rain shadow. Examples include the Great Basin Desert in North America and the Patagonian Desert in South America.
5. Semiarid Desert: A semi-arid desert is a transitional biome characterized by a combination of arid and more moderate conditions. It receives more precipitation than typical deserts, usually between 250mm and 500mm annually. While not as dry as true deserts, semi-arid regions still face water scarcity and can exhibit features like sparse vegetation and variable temperatures. The steppe biome is an example of a semi-arid environment.

 Characteristics of Deserts

1. Low Precipitation: Deserts receive very little rainfall, often less than 250 millimeters (10 inches) annually.
2. Extreme Temperatures: Daytime temperatures can be extremely high, while nights can be cold, especially in hot deserts.
3. Sparse Vegetation: Vegetation is adapted to arid conditions, with plants having water-conserving features like succulence or deep root systems.
4. Sand Dunes: Many deserts feature extensive sand dunes, shaped by wind erosion and deposition.
5. Limited Surface Water: Rivers and lakes are rare, and when present, they are often intermittent.
6. Adapted Fauna: Animal life includes species adapted to conserve water and withstand temperature extremes, such as camels and reptiles.
7. Wind Erosion: Wind plays a significant role in shaping the landscape, leading to the formation of rock structures and sand dunes.
8. Harsh Sunlight: Intense sunlight contributes to high evaporation rates, exacerbating aridity.

Processes of wind formation

Wind erosion involves the movement of soil and sediment by the force of wind. There are several processes contributing to wind erosion:

1. Deflation: This is the lifting and removal of loose, dry particles such as sand, silt, and clay from the surface. Wind removes the finer particles, leaving coarser material behind.
2. Abrasion: Wind-blown particles can act like sandpaper, wearing away surfaces they come in contact with. This process contributes to the smoothing and sculpting of rocks and landforms.
3. Saltation: Small particles, like sand, are lifted and transported in short hops by the wind. As they collide with the ground, they can dislodge more particles, contributing to erosion.
4. Suspension: Fine particles, such as dust and silt, can be lifted into the air and transported over long distances by wind. This suspended material can have environmental and health implications.

Features of Wind Erosion

1. Deflation Hollows: These are depressions formed as wind removes fine particles, leaving coarser materials behind.
2. Yardangs: These are streamlined rock formations created by the abrasion of wind-borne particles.
3. Sand Dunes: Wind shapes and moves sand into various dune forms, such as crescent, linear, and star dunes.
4. Ventifacts: These are rocks sculpted by wind-blown particles, exhibiting facets and sharp edges.
5. Loess Deposits: Fine silt and clay particles carried by the wind can settle and accumulate, forming thick deposits called loess.

Features of Wind Deposition

1. Sand Sheets: Wide expanses covered by a relatively thin layer of wind-deposited sand.
2. Sand Drifts: Accumulations of sand around obstacles like vegetation or rocks.
3. Loess Deposits: Wind-blown fine particles settling and forming thick, fertile deposits.
4. Playas: Temporary lakes or salt pans formed as wind-carried sediments accumulate.

Man's Survival Strategies in Desert Environment

1. Nomadic Lifestyle: Some desert communities adopt a nomadic lifestyle, moving in search of water and grazing land for livestock.
2. Water Harvesting: Implementing techniques like rainwater harvesting, digging wells, and constructing qanats (underground channels) to secure water sources.
3. Vegetation Management: Utilizing drought-resistant crops, practicing agroforestry, and preventing overgrazing to maintain soil stability.
4. Traditional Knowledge: Drawing on indigenous knowledge to understand and adapt to the desert environment, including efficient water usage and survival skills.

EVALUATION: 1. What is desert?

2. Identify and discuss 4 features of wind formation
3. Mention 5 characteristics of a desert.
4. Identify 5 strategies for Man's survival in a desert.

CLASSWORK: As in evaluation

CONCLUSION: The teacher commends the students positively