Lesson Notes By Weeks and Term v5 - Grade 4

Lesson Video

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Performance objectives

• Identify physical properties of materials.
• Classify materials based on their properties.
• Describe how heating and cooling change water.
• Explain reversible and irreversible changes.

Lesson summary

This week, we'll be exploring the fascinating world of matter and materials, specifically focusing on their properties and how they can change. Understanding matter and materials is crucial because everything around us – from the desks we sit at to the food we eat – is made of them. Knowing about their properties helps us choose the right materials for different purposes and understand how things work. In South Africa, understanding materials is particularly important for building homes, creating sustainable products, and managing our resources wisely.

Lesson notes

What is Matter? Matter is anything that has mass and takes up space. Essentially, it's everything around you! Air, water, rocks, your desk, even you are made of matter. What are Materials? Materials are the substances that things are made of. Wood, plastic, metal, glass, and fabric are all examples of materials.

Physical Properties of Materials: Physical properties are characteristics that we can observe or measure without changing the material into something new.

Here are some common physical properties: Colour: The appearance of a material in terms of hue (e.g., red, blue, green).

Example: A watermelon has a green rind and a red inside.

Texture: How a material feels to the touch (e.g., smooth, rough, bumpy).

Example: Sandpaper feels rough, while glass feels smooth. Think about the difference between the texture of a mielie (corn) and a pumpkin.

Hardness: How resistant a material is to scratching or denting.

Example: A diamond is very hard; it can scratch almost anything. A butter is soft.

Flexibility: How easily a material can bend without breaking.

Example: A rubber band is flexible, while a ceramic tile is not. Think about the flexibility of a thin branch versus a thick tree trunk.

Transparency: How much light passes through a material.

Example: Glass is transparent, wood is opaque (no light passes through), and some plastics are translucent (some light passes through). Think about the difference between the clear plastic of a juice bottle and a solid plastic container.

Magnetism: Whether a material is attracted to a magnet.

Example: Iron and steel are magnetic, while wood and plastic are not.