First Term Lesson Note for Week Six

Class : JSS 1

Subject : Basic Technology

Topic : Identification of Metals

Duration : 80 Minutes

Periods : Double Period

Learning Objectives : By the end of the lesson learners will be able to :

I. Défine Metals

II. State the Properties of Metals

III. List the Classes of Metals and give examples

DEFINITION OF METAL

METAL is a type of solid mineral substance that is usually hard and shiny. It conducts heat and electricity can travel through it. Metals have characteristics which are different from those of the non-metals such as wood, plastics ceramics, rubber etc

PROPERTIES OF METAL

Metals can be identified by the following physical properties:

Conductivity: Some metals have the ability to conduct heat and electricity.

Fusibility: Some metals have the ability to be melted and cast into shapes.

Magnetic: Some metals have the ability to attract iron.

Ductility: Some metals have the ability to be drawn or stretched out into wires without breaking.

Brittleness: Some metals have the ability to break or crack , when hit on the ground

Malleability: Some metals have the ability to be hammered or beaten into shape without cracking.

Toughness: Some metals have the ability to withstand (resist) bending, breaking, cracking or stretching.

Density: Some metals have weight and volume.

Colour (lustre): Some metals have the ability of having a shining appearance when polished.

CLASSES OF METAL

The metals used in engineering can be classified into two categories

Ferrous metals and their alloys

Non-ferrous metals and their alloys

FERROUS METALS AND THEIR ALLOYS

This group of metals contains iron. The metals are, therefore, magnetic. Examples include wrought iron, cast iron and various grades of sioteel (High carbon steel, low carbon steel, etc)

NON-FERROUS METALS AND THEIR ALLOYS

This group of metals have no iron . These metals are therefore not magnetic. Examples are aluminum, copper, brass, etc.

EVALUATION

1. What are metals?
2. State five properties of metal.
3. List the two classes of metals
4. Differentiate between ferrous and non-ferrous metal.
5. Mention three examples of each types of metals.

CONCLUSION : The teacher summarizes the lesson by focusing on the learning objectives for a better understanding.