Metals are known for their shiny appearance, conductivity of heat and electricity, and malleability. Common examples include iron, copper, and gold. Alloys are mixtures of metals or a metal mixed with one or more other elements. They are often stronger or have other improved properties compared to pure metals.
▸ Alloy — A mixture of two or more elements, at least one of which is a metal.
Example: Steel (iron and carbon), Brass (copper and zinc).
★ Real-world:
Steel is an alloy of iron and carbon, making it much stronger than pure iron. It's used in buildings, bridges, and vehicles. Bronze, an alloy of copper and tin, is used for statues and medals.
Water hardness refers to the concentration of dissolved minerals, primarily calcium and magnesium, in water. Hard water can cause scale buildup in pipes and appliances and makes soap less effective.
✎ Activity: Gather samples of iron (like nails) and place them in separate containers with salt water and plain water. Observe which one rusts faster over a few days. Discuss why salt might speed up rusting.
• Complete the activity described and discuss your answer with a partner or teacher.
Expected outcome: Learners can explain what they practised and connect it to the lesson objective.
Audio narration — reads aloud, works offline
In your own words, summarise the main idea of this lesson.