Unlocking the Secrets of Alloys: Composition, Properties, and Applications Basic Technology JSS 3 First Term Lesson Notes Week 5

Basic Technology on Alloy Composition, Properties, and Uses for JSS 3, First Term, Week 5.

Lesson Plan: Alloy Composition, Properties, and Uses

1. Subject: Basic Technology
2. Class: JSS 3
3. Term: First Term
4. Week: Week 5
5. Age: 13 years

Topic: Alloy Composition, Properties, and Uses

Sub-topic:

• Definitions of Alloys
• Composition of Alloys
• Properties and Uses of Common Alloys

Duration:

• 40 minutes

Behavioral Objectives:

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

• Define alloys and understand their composition.
• Identify the properties of common alloys.
• Describe the uses of different alloys in various applications.

Keywords:

• Alloy
• Composition
• Properties
• Bronze
• Brass
• Aluminium

Set Induction:

• Begin with a brief discussion on metals and their uses in everyday life. Ask students if they know what alloys are and how they differ from pure metals.

Entry Behavior:

• Students should have a basic understanding of metals and their characteristics.

Learning Resources and Materials:

• Chart showing different alloys and their compositions.
• Samples of bronze, brass, and aluminum.
• PowerPoint presentation on alloy properties.

Building Background/Connection to Prior Knowledge:

• Review previous lessons on metals and their properties, linking this to how alloys enhance certain properties for specific applications.

Embedded Core Skills:

• Critical thinking (analyzing properties).
• Communication (sharing findings with peers).
• Practical skills (handling materials).

Learning Materials:

• Textbooks on Basic Technology.
• Visual aids (posters/charts).

Reference Books:

• Lagos State Scheme of Work for Basic Technology
• Textbook: Basic Technology for Junior Secondary Schools by A.A. Afolabi

Instructional Materials:

• Visual presentation on alloy composition and properties.
• Samples of metals and alloys for demonstration.

Content:

1. Definition of Alloys
   • Alloys are mixtures of two or more metals, or a metal and a non-metal, which enhance their properties.
2. Common Alloys
   • Bronze:
     • Composition: 90% Copper, 10% Tin
     • Properties: Hard, strong, corrosion-resistant
     • Uses: Sculptures, tools, and musical instruments.
   • Brass:
     • Composition: 70% Copper, 30% Zinc
     • Properties: Harder than copper, malleable
     • Uses: Musical instruments, kitchen fittings, and decorative items.
   • Aluminium Alloys:
     • Composition: 95% Aluminium, 5% Copper or Magnesium
     • Properties: Light, strong, resistant to corrosion
     • Uses: Aircraft construction, window frames, and doors.

15 Fill-in-the-Blank Questions with Options (a, b, c, d):

1. An alloy is a mixture of _____ (a) metal, (b) non-metal, (c) both, (d) none of the above.
2. Bronze is made primarily of copper and _____ (a) zinc, (b) tin, (c) aluminium, (d) nickel.
3. Brass contains _____ (a) 30% copper, (b) 70% copper, (c) 50% copper, (d) 10% copper.
4. The main property of bronze is that it is _____ (a) weak, (b) soft, (c) strong, (d) brittle.
5. Aluminium alloys are known for being _____ (a) heavy, (b) light, (c) dense, (d) strong.
6. _____ is used for making musical instruments (a) Copper, (b) Brass, (c) Steel, (d) Bronze.
7. The property of brass that makes it suitable for kitchen fittings is its _____ (a) strength, (b) malleability, (c) color, (d) weight.
8. A common use of bronze is in _____ (a) window frames, (b) tools, (c) airplanes, (d) jewelry.
9. The main advantage of using alloys is _____ (a) cost, (b) strength, (c) weight, (d) size.
10. Aluminium is often alloyed with _____ (a) zinc, (b) copper, (c) both, (d) none.
11. Alloys are typically _____ than pure metals (a) stronger, (b) weaker, (c) lighter, (d) softer.
12. The composition of brass is _____ (a) 50% copper, 50% zinc, (b) 70% copper, 30% zinc, (c) 100% copper, (d) 40% copper, 60% zinc.
13. A key characteristic of aluminium alloys is their _____ (a) ductility, (b) density, (c) conductivity, (d) thermal expansion.
14. Tin is used in making _____ (a) brass, (b) bronze, (c) aluminium, (d) steel.
15. The strength of alloys makes them suitable for _____ (a) tools, (b) toys, (c) decorations, (d) food.

15 FAQs with Answers:

1. What is an alloy?
   An alloy is a mixture of two or more metals or a metal and a non-metal.
2. Why are alloys used?
   Alloys are used because they often have improved properties compared to pure metals.
3. What are some examples of alloys?
   Common examples include bronze, brass, and steel.
4. What is bronze made of?
   Bronze is typically made of 90% copper and 10% tin.
5. What is brass used for?
   Brass is used for musical instruments, plumbing fittings, and decorative items.
6. What makes aluminium alloys special?
   Aluminium alloys are light and strong, making them ideal for aerospace applications.
7. Can alloys rust?
   Some alloys can rust, but many are designed to resist corrosion.
8. What is the main property of brass?
   Brass is known for its malleability and strength.
9. Are alloys more expensive than pure metals?
   It depends on the materials used, but alloys can be more costly due to their complex compositions.
10. Is bronze softer than brass?
    Bronze is generally softer than brass, which is harder due to its zinc content.
11. How are alloys made?
    Alloys are made by melting the constituent metals together and allowing them to cool.
12. What is the main use of bronze?
    Bronze is commonly used in sculptures and tools.
13. Can you recycle alloys?
    Yes, many alloys can be recycled without losing their properties.
14. What is the significance of alloy composition?
    The composition determines the alloy’s properties and suitability for specific uses.
15. How does temperature affect alloys?
    Temperature can change the properties of alloys, affecting their strength and ductility.

Presentation:

• Step 1: Review the previous lesson on metals.
• Step 2: Introduce the new topic of alloys, highlighting their importance.
• Step 3: Encourage students to share what they know about alloys and correct them as necessary.

Teacher’s Activities:

• Present information using visuals and samples.
• Facilitate group discussions.
• Conduct demonstrations with alloy samples.

Learners’ Activities:

• Participate in discussions.
• Handle alloy samples and describe their properties.
• Complete the fill-in-the-blank and FAQ activities.

Assessment:

• Evaluate students’ understanding through their responses during discussions and the fill-in-the-blank questions.

10 Evaluation Questions:

1. Define an alloy.
2. List two common alloys and their compositions.
3. Describe one property of bronze.
4. Explain why brass is used for musical instruments.
5. What are the advantages of using alloys?
6. How does the composition of aluminium alloys benefit their use?
7. Give an example of an application for bronze.
8. Why is it important to know the properties of alloys?
9. How can alloys be recycled?
10. What is the effect of zinc on the properties of brass?

Conclusion:

• Review the key points discussed in the lesson.
• Encourage students to explore the use of alloys in their daily lives.
• Mark the fill-in-the-blank questions for understanding and provide feedback as necessary.