Class: Senior Secondary School 1 (SS1, SS 1, SSS1, SSS 1)
Term: 1st Term
Week: 9
Age: 15 years
Duration: 45 minutes
Subject: Metal Work
Curriculum Theme: Pre-Vocational Studies
Previous Lesson: Physical Properties of Metals: Ductility, Malleability and Hardness.
Topic: Production of metals, types of metals, and their sources.
Subject Matter: Sources of metals such as iron ore, copper, and aluminium; types of metals including steel, pig iron, and cast iron; methods of extracting ores from the earth’s crust; blast furnace for metal production; uses of listed metals.

Specific Objectives

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

Cognitive Domain:

Identify common sources of metals like iron ore, copper, and aluminium.
Distinguish between different types of metals such as steel, pig iron, and cast iron.
Describe the basic methods of extracting ores from the earth’s crust.
Explain the role of a blast furnace in metal production.
State various uses of iron, copper, and aluminium.

Affective Domain:

Appreciate the importance of metal production in daily life.
Value the processes involved in transforming raw materials into useful metals.

Psychomotor Domain:

Identify samples or pictures of different metals and their ores.
Sketch a simple diagram illustrating a blast furnace.

Participate actively in discussions about metal production.

Reference Materials

The following resources were used in planning this lesson:

9 Years Basic Education Curriculum for Senior Secondary Schools.
State Unified Scheme of Work for Senior Secondary Schools.
Metalwork for Senior Secondary Schools by A.O. Aina.
www.nigeriancurriculum.com

Instructional Materials

The teacher will teach this lesson with the aid of:

Metal samples (e.g., iron rod, copper wire, aluminium sheet).
Pictures of various metal ores (e.g., iron ore, bauxite, copper ore).
Diagrams illustrating a blast furnace.
Chalkboard/Whiteboard and markers/chalk.

Rationale for the Lesson

This lesson helps pupils understand where common metals come from and how they are processed. Knowing about metal production and types of metals enables pupils to appreciate the materials around them and their applications in daily life and industries.

Prerequisite/Previous Knowledge

Pupils have basic knowledge of different materials and their general properties from previous lessons.

Lesson Content/Board Summary

Production of Metals, Types of Metals, and Their Sources

1. Sources of Metals

Metals are obtained from naturally occurring mineral deposits known as ores, which are found within the Earth’s crust.

The following are common sources of metals:

Iron Ore: The primary source for producing iron and steel.
Copper Ore: The main source for extracting copper.
Bauxite: The principal ore from which aluminium is extracted.

2. Types of Metals

Metals can be categorised based on their composition and properties. Iron-based metals are particularly important in metalwork.

Key types of iron-based metals include:

Pig Iron: This is an intermediate product of smelting iron ore in a blast furnace. It has a high carbon content (3.5-4.5%) and is very brittle. It is not directly used for engineering purposes but is a raw material for cast iron and steel.
Cast Iron: Produced by re-melting pig iron, often with scrap iron and other additives. It contains 2-4% carbon and is hard and brittle but has excellent casting properties.
Steel: An alloy of iron and carbon, with carbon content typically less than 2%. Steel is known for its strength, ductility, and versatility, making it suitable for a wide range of applications.

3. Methods of Extracting Ores from the Earth’s Crust

The process of obtaining metal ores from the ground is called mining. Different methods are used depending on the depth and location of the ore deposit.

Common methods of ore extraction include:

Surface Mining (Open-pit mining): Used when ore deposits are close to the surface. Large open pits are dug to remove the ore.
Underground Mining: Employed for deeper ore deposits, involving the creation of shafts, tunnels, and rooms to access and extract the ore.
Dredging: Used to recover minerals from riverbeds, lakebeds, or shallow ocean floors.

4. Blast Furnace for Metal Production (Iron)

The blast furnace is a tall, cylindrical industrial furnace used for smelting iron ores to produce pig iron. It operates continuously.

The process involves:

Charging: Iron ore, coke (as fuel and reducing agent), and limestone (as flux) are fed into the top of the furnace.
Combustion: Hot air, often enriched with oxygen, is blown into the bottom of the furnace, burning the coke to produce intense heat and carbon monoxide gas.
Reduction: Carbon monoxide reacts with the iron ore, reducing the iron oxides to molten iron.
Slag Formation: Limestone reacts with impurities in the ore to form molten slag, which floats on top of the heavier molten iron.
Tapping: Molten pig iron and slag are periodically tapped from the bottom of the furnace.

5. Uses of Listed Metals

Each metal possesses unique properties that make it suitable for specific applications.

Uses of common metals include:

Iron/Steel: Used extensively in construction (beams, reinforcing bars, structural frameworks), manufacturing (vehicles, machinery, tools, appliances), and bridge building.
Copper: Highly valued for electrical wiring due to its excellent conductivity, plumbing pipes, roofing, coinage, and in alloys like brass and bronze.
Aluminium: Used in aircraft components, beverage cans, window frames, cooking utensils, electrical transmission lines, and foil due to its lightweight and corrosion resistance.

Teaching Methods/Instructional Techniques

Discussion, Lecture, Demonstration, Question and Answer, Visual Aids

Instructional Procedures

Step 1: Introduction

Time: 5 minutes
Teaching Skill: Set Induction
Teacher’s Activity: The teacher greets the pupils and asks them to name some common metal objects they use daily (e.g., spoons, pots, keys, car parts). The teacher then asks where these metals originally come from.
Pupils’ Activity: Pupils respond by naming metal objects and offering ideas about metal origins.
Learning Point: Pupils are engaged and their prior knowledge is activated, linking the lesson to their daily lives.

Step 2: Introduction of Sources of Metals

Time: 5 minutes
Teaching Skill: Explanation/Identification
Teacher’s Activity: The teacher introduces the topic “Production of Metals, Types of Metals, and Their Sources.” The teacher then explains that metals come from ores and shows pictures of iron ore, copper ore, and bauxite, identifying them as sources for iron, copper, and aluminium respectively.
Pupils’ Activity: Pupils listen attentively, observe the pictures, and identify the different ore samples.
Learning Point: Pupils identify common sources of various metals.

Step 3: Explanation of Types of Metals

Time: 8 minutes
Teaching Skill: Elucidation/Differentiation
Teacher’s Activity: The teacher explains the different types of iron-based metals: pig iron, cast iron, and steel. The teacher describes their basic properties and how they relate to each other in the production process, using simple language.
Pupils’ Activity: Pupils listen, take notes, and ask questions for clarification regarding the differences between the metal types.
Learning Point: Pupils distinguish between pig iron, cast iron, and steel.

Step 4: Discussion of Methods of Ore Extraction

Time: 8 minutes
Teaching Skill: Explanation/Illustration
Teacher’s Activity: The teacher explains the common methods used to extract ores from the Earth’s crust, such as surface mining, underground mining, and dredging. The teacher may use simple diagrams or descriptions to illustrate these methods.
Pupils’ Activity: Pupils listen and note down the different extraction methods, asking questions about their processes.
Learning Point: Pupils describe basic methods of extracting ores.

Step 5: Explanation of Blast Furnace for Iron Production

Time: 8 minutes
Teaching Skill: Demonstration/Explanation
Teacher’s Activity: The teacher explains the working principle of a blast furnace, focusing on its role in producing pig iron from iron ore. The teacher uses a diagram of a blast furnace to illustrate the process of charging, combustion, reduction, and tapping.
Pupils’ Activity: Pupils observe the diagram, listen to the explanation, and attempt to sketch a simple representation of the blast furnace.
Learning Point: Pupils explain the role of a blast furnace in metal production.

Step 6: Discussion of Uses of Metals

Time: 5 minutes
Teaching Skill: Question and Answer/Application
Teacher’s Activity: The teacher leads a discussion on the various uses of iron/steel, copper, and aluminium, linking them to the properties of each metal. The teacher encourages pupils to give examples from their environment.
Pupils’ Activity: Pupils contribute examples of metal uses and discuss why certain metals are chosen for particular applications.
Learning Point: Pupils state various uses of iron, copper, and aluminium.

Step 7: Evaluation/Review

Time: 5 minutes

Teaching Skill: Questioning/Assessment

Teacher’s Activity: The teacher evaluates the learning by asking the following questions:

Define pig iron.
List two sources of metals.
Mention two types of metals.
State one method of extracting ores from the earth’s crust.
Give two uses of copper.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Pupils demonstrate understanding of the lesson.

Step 8: Conclusion

Time: 1 minute
Teaching Skill: Summarization
Teacher’s Activity: The teacher briefly summarizes the key points of the lesson, reiterating the importance of metals and their production processes. The teacher assigns homework which includes drawing a simple diagram of a blast furnace.
Pupils’ Activity: Pupils listen to the summary and note down the homework.
Learning Point: Pupils consolidate their learning and prepare for further study.

Lesson Keywords

Ore – A naturally occurring rock or mineral from which a metal or valuable mineral can be extracted.
Pig Iron – An intermediate product of iron smelting, high in carbon and brittle.
Cast Iron – An iron alloy with 2-4% carbon, known for its hardness and casting properties.
Steel – An alloy of iron and carbon (less than 2% carbon), known for its strength and ductility.
Blast Furnace – A large industrial furnace used for smelting iron ores to produce pig iron.
Smelting – The process of extracting metal from its ore by heating it.
Bauxite – The principal ore of aluminium.

Differentiation

The teacher will provide visual aids like pictures and diagrams for visual learners. Opportunities for group discussion will cater to social learners. The teacher will offer simplified explanations for pupils who may struggle and provide challenging questions for advanced learners to deepen their understanding of metal properties and industrial processes.

Note for teachers using this lesson plan

Teachers should ensure they have adequate visual aids, especially diagrams of the blast furnace and pictures of different ores and metals, to make the lesson more engaging and understandable. Encourage pupils to bring small metal objects from home (e.g., old keys, copper wire scraps) for a more practical feel to the lesson.