First Term Lesson Note for Week Nine

Class : JSS 1

Subject : Basic Technology

Topic : Processing and Uses of Metals

Duration : 80 Minutes

Periods : Double Period

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

I. Identify the methods of processing metals

II. State the Uses of Ferrous and Non-ferrous metals

Instructional Material : Picture Chart showing the methods of processing metals.

Reference Book : Evans Basic Technology for Junior Secondary School.

PROCESSING METALS

Most metals do not occur in a pure state. They are usually combined with other metals and earthly impurities to form what is called mineral ore.

The ore is then mined and processed to extract the metal of interest. The extraction process differs from metal to metal.

The following are the methods of extracting metals from their ores:

I. Casting,

II. Smelting

III. Annealing

Casting: Casting is the process of melting and pouring molten metal into the mould to take the shape of the mould when it cools down or solidifies.

Smelting:Smelting is the process of extracting metals from iron-ore dug from the ground.

Annealing: Annealing is the process by which metals can be softened.

USES OF METAL

Alloy metal composition Properties

Brass 65%copper and 35%zinc Soft material

Gilding metal 80% copper and 20 % zinc Polishes well and no corrosion

Bell metal 78% copper and 22% zincLouder in sound than other metals

Ferrous metals Uses

Cast iron : Cast iron in the manufacturing of machine parts , pipes, radiators, stoves, engine blocks

Carbon steel : Carbon steels are used in the manufacturing of the automobile bodies gears, hacksaws ,hammers ,drill,

Steel Alloy steels are used in the manufacturing of cables, steels, rail, wires , springs , shoves, ball-bearing, chisels etc.

Wrought Iron : The wrought iron is used in the manufacturing of nails ,horse shoes, pipe ,wires, roofing sheets

Non-ferrous metal and Uses

Aluminium : Aluminium is used for manufacturing aircraft, cooking pots for its lightness.

Copper : Copper is used for making telephone wires, water heater, pipes ,electric cables.

Zinc : Zinc is used for the coating of iron and steel as a protection against rusting . It is used for wire-fence, water tank reservoir, bucket.

Brass Brass is for making musical instrument screws clocks.

Silver : Silver is for ornament work ,mirror.

Nickel : Nickel is used for plating iron and materials to give a shining slivering appearance. It is also used for making cooking pots and sauce pan.

Lead : Lead is used for making lead pipes , storage batteries, chemicals and cover electric cables.

Tin : Tin is used for making engine bearing, ball-bearing medals, coins , statues and collapsible tubes.

EVALUATION

1. Explain the following methods of processing of metals

(i) annealing

(ii) smelting

(iii) casting.

2. State the uses of the following metals

(i) alloy metals

(ii) ferrous metals

(iii) non-ferrous metals.

ASSIGNMENT

Read on Identification of Ceramics, Plastics and Rubber from Basic Technology (JSS1) by Evans. Pages 32-35

WEEKEND ASSIGNMENT

1. ___________________ is a type of solid mineral substance that is usually hard and shiny and that heat and electricity can travel through (a) Plastic (b) Rubber (c) Metal (d) Ceramics

2. Some metals have the ability to be hammered or beaten into shape without cracking .This quality is known as (a) malleability (b) ductility (c) toughness (d) fusibility

3. The group of metals that contains iron is known as (a) ferrous metals (b) non-ferrous metals (c) alloys. (d) terrazzo

4. The group of metals that has no iron is not magnetic. Examples are as follow except(a) aluminium (b) copper (c) steel (d) brass

5. _______________ is the process by the which metals can be softened.(a) Casting (b) Smelting (c) Annealing (d) Riveting

THEORY

1. Define and state the properties of metals.

2. State the classes of metals with examples.

3. Explain the following methods of processing of metals :

(i) annealing

(ii) smelting

(iii) casting.

4. State the uses of the following metals :

(i) alloy metals

(ii) ferrous metals

(iii) non-ferrous metals