Lesson Notes By Weeks and Term - Senior Secondary 1

TERM – 1^ST TERM

WEEK NINE

Class: Senior Secondary School 1

Age: 15 years

Duration: 40 minutes of 5 periods each

Date:

Subject: Geography

Topic: ROCKS

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

1. Identify the major types of rocks.
2. Differentiate between the characteristics of igneous, sedimentary and metamorphic, rock in terms of structure, colour, texture, and permeability
3. Explain the mode of formation of each type of rocks and Examine the importance of rocks to Man

INSTRUCTIONAL TECHNIQUES: Identification, explanation, questions and answers,

demonstration, videos from source

INSTRUCTIONAL MATERIALS: Videos, loud speaker, textbook, pictures

INSTRUCTIONAL PROCEDURES

PERIOD 1-2

NOTE

ROCKS

Rocks are naturally occurring solid substances composed of minerals, mineraloids, or organic materials. They form through geological processes such as cooling and solidification of molten magma, compression and cementation of sediments, or alteration of pre-existing rocks.

Types of rocks

 Rocks can be categorized into three main types:

1. Igneous Rocks: It is formed from the cooling and solidification of molten magma or lava. Examples of igneous rocks includes: Granite (intrusive), basalt (extrusive).

2. Sedimentary Rocks: It result from the accumulation, compaction, and cementation of sediments over time. Examples of sedimentary rocks are; Sandstone, limestone, shale.

3. Metamorphic Rocks: Are formed through the alteration of existing rocks (igneous, sedimentary, or other metamorphic rocks) by heat and pressure. Examples include: Marble (from limestone), schist, slate.

Differences between igneous, sedimentary and metamorphic rocks

1. Igneous Rocks:

1. Structure: Typically have a crystalline structure, with mineral grains formed during the cooling process. Can be classified into intrusive (formed below the Earth's surface) or extrusive (formed at the Earth's surface).
2. Color: Varied, depending on mineral composition. For example, granite is light-colored, while basalt is dark.
3. Texture: Can be fine-grained (small crystals) or coarse-grained (large crystals) based on the cooling rate.
4. Permeability: Generally low, as the interlocking crystals create a compact structure.

2. Sedimentary Rocks:

1. Structure: Composed of layers (bedding) formed by the accumulation of sediments over time. May contain fossils.
2. Color: Diverse colors, often reflecting the minerals present. For instance, limestone is commonly light-colored.
3. Texture: Varies from fine-grained (clay and silt) to coarse-grained (sand and pebbles). Can be clastic, chemical, or organic in origin.
4. Permeability: Highly variable. Sandstone tends to be more permeable than shale.

3. Metamorphic Rocks:

1. Structure: Display foliation (layering) due to the alignment of minerals under pressure. Can be foliated (with visible layers) or non-foliated.
2. Color: Altered from the original rock; color depends on mineral composition. For instance, marble is often light-colored.
3. Texture: Can be fine-grained or coarse-grained, depending on the degree of metamorphism.
4. Permeability: Generally low, as the minerals are compacted and often interlocked during metamorphism.

Mode of formation

1. Igneous Rocks: Igneous rocks form from the cooling and solidification of molten magma or lava. When magma cools beneath the Earth's surface, intrusive igneous rocks (like granite) are formed. If lava cools at the Earth's surface, extrusive igneous rocks (like basalt) are created.
2. Sedimentary Rocks: Sedimentary rocks form through the accumulation, compaction, and cementation of sediments. Sediments can be derived from the weathering and erosion of pre-existing rocks or from the remains of living organisms. Over time, these sediments are compacted and cemented to form rocks such as sandstone, limestone, and shale.
3. Metamorphic Rocks: Metamorphic rocks result from the alteration of existing rocks (igneous, sedimentary, or other metamorphic rocks) by heat, pressure, or chemically active fluids. This alteration occurs deep within the Earth's crust. The original rocks, called protoliths, undergo changes in mineralogy, texture, and structure, leading to the formation of metamorphic rocks like marble, schist, and slate.

Importance of rocks to Man

Rocks hold significant importance for humanity due to various reasons:

1. Construction Materials: Many rocks, such as granite, limestone, and sandstone, serve as essential construction materials for buildings, roads, and infrastructure.
2. Natural Resources: Rocks contain valuable resources like metals (gold, silver, copper) and minerals (phosphates, gypsum) that are crucial for manufacturing, technology, and agriculture.
3. Energy Sources: Certain rocks, like coal and shale, are sources of fossil fuels, providing energy for electricity generation and industrial processes.
4. Water Storage and Filtration: Porous rocks like sandstone act as natural reservoirs for groundwater, and impermeable rocks can serve as barriers for groundwater pollution.
5. Landscaping and Ornamental Uses: Decorative rocks like marble and granite are used for aesthetic purposes in sculptures, monuments, and interior design.
6. Geological Insights: Studying rocks helps scientists understand Earth's history, past environmental conditions, and geological processes.
7. Cultural and Historical Significance: Some rocks hold cultural or historical importance, such as gemstones and precious minerals used in jewelry and artifacts.

EVALUATION: 1. What is rocks?

2. Identify the 3 types of rocks and explain them.
3. Discuss the formation of igneous rock
4. Give 4 importance of rocks to Man

CLASSWORK: As in evaluation

CONCLUSION: The teacher commends the students positively