Lesson Plan

• Describe what an alloy is and give at least three examples.
• Explain why alloys are generally harder and stronger than the pure metals they contain.
• Identify the four main mechanisms that increase alloy hardness (solid‑solution, precipitation, grain‑size reduction, intermetallic compounds).
• Compare the properties of selected alloys with those of their constituent pure metals.
• Apply knowledge to choose a suitable alloy for a specified real‑world application.

• Projector and laptop with presentation slides
• Printed worksheet containing alloy tables and diagrams
• Sample alloy specimens (e.g., brass, stainless steel, aluminium alloy)
• Diagram handout illustrating solid‑solution strengthening
• Whiteboard and markers
• Exit‑ticket slips

Begin with the question, “What makes a kitchen knife stay sharp longer than a pure metal blade?” Connect this to students’ prior knowledge of pure metal properties and outline that by the end of the lesson they will be able to state why alloys are harder, stronger, and more useful.

1. Do‑now (5'): Quick quiz on properties of pure metals.
2. Mini‑lecture (10'): Definition of alloys, why they are useful, and presentation of the schematic diagram.
3. Mechanisms activity (15'): Small‑group analysis of solid‑solution, precipitation, grain‑size reduction, and intermetallic compounds using handouts.
4. Case‑study comparison (10'): Examine the provided alloy table and match properties to real‑world applications.
5. Think‑pair‑share (5'): Choose an alloy for a lightweight bicycle frame and justify the choice.
6. Formative check (5'): Exit ticket – one sentence summarising why alloys are stronger than pure metals.

Recap the four strengthening mechanisms and the key advantages of alloys. Collect exit tickets to gauge understanding, and assign homework: research an alloy not covered today and write a short paragraph describing its composition and a practical use.