In this section learners will investigate and contrast the properties of metals and materials that are not metallic (so-called 'non-metals'). You could draw their attention to metallic and non-metallic items in the classroom, or in pictures, as an introduction to the topic and related activities.

Explanation of the new words to be covered in this section, associated with metals.

• Properties: The words we use to describe a certain type of matter, a material or even an object, e.g. a property of gases is that they can be compressed.
• Metal: A shiny solid that can conduct heat or electricity and can be formed into sheets or wire.
• Lustre/lustrous: The 'shine' we see when light reflects off the surface of a metallic object such as a key or a coin. We say that metals are 'lustrous'.
• Dense: Dense materials have lots of particles packed close together. Less dense materials have fewer particles packed together. When we compare a metal teaspoon with a plastic teaspoon of the same size and shape, the metal teaspoon would be heavier, because metal is more dense than plastic. NB: Do not refer to dense objects as 'heavy' and less dense objects as 'light'. This creates a misconception that density is the same as mass. Density is the mass per unit volume. Mass does therefore influence density, but it is not the same as density. Rather explain it as how closely the particles in a substance is packed, which includes both mass and volume. The more particles that can fit into a specific size/shape, the more dense the object will be.
• Malleable: Malleable materials can be hammered into different shapes without breaking. As a simple example you could think of bending a paper clip into a new shape.

Here, the conversation could be directed in such a way that learners realise that when we cook food, we heat the outside of the pot, the food cooks on the inside. That means the heat that cooks the food travels through the metal. Would heat travel through plastic in the same way? No, the plastic would melt. Would heat travel through wood in the same way? No, the wood would burn.

Here, a comment about skills of observation may be appropriate. What are skills of observation? What does it mean to observe something? Does observation only refer to things we can see? No, we can also observe (hear) sounds, observe (smell) odours, observe (feel) textures and observe (taste) flavours. Learners might also find it difficult to express what they observe. Encourage them to find words to write down, or say what they see, hear, smell, feel and taste. This will help to develop their science vocabulary.

Explanation of new words in this section

• Dull: Dull is the opposite of shiny. When a surface is shiny, it acts like a mirror. An example could be paper or your school shirt. NB: The reflection of light is not done at this level, but dullness can be defined as the scattered reflection of light off a surface. Light is uniformly reflected off a shiny surface, for example off a mirror.
• Brittle: Brittle materials crack or break easily. Glass is brittle, and so is clay (pottery).
• Insulator: Insulators are materials which prevent the flow of heat (thermal insulators) or electrical current (electrical insulators). Glass, porcelain, pottery and plastic are examples.

This conversation could be linked to an earlier conversation in which learners were helped to discover that metals are good conductors of heat ("when we cook food, we heat the outside of the pot, but the food cooks on the inside'). That means the heat can also travel along the handle of the pot or pan and burn our hands. Would heat travel through plastic or wood in the same way? No, the plastic or wood acts as insulator, to protect our hands from the heat. These materials do not conduct heat well. Learners could also be reminded that a hot pot or pan could also be handled with a thick cloth or oven mitt to protect the hands. Cloth does not conduct heat well either.