Lesson Notes By Weeks and Term v5 - Grade 4

Lesson Video

This page supports the lesson note with a companion video and a short classroom-ready summary.

For class groups and homework, share this lesson page so learners also get the summary, objectives, and full lesson context.

Performance objectives

• Describe the three states of matter with SA examples.
• Explain how heating and cooling change matter.
• Describe properties of materials and their uses.
• Identify water sources in South Africa.
• Explain why and how we should save water.

Lesson summary

This week, we're going to revise and consolidate the important Natural Sciences and Technology concepts you learned in Grade

4. This is like sharpening your tools before building something new! By revisiting these ideas, you'll be better prepared for the exciting new things we'll learn later in the year. We'll focus on topics that are foundational to understanding the world around us, especially in South Africa. Understanding these concepts helps us understand everything from why our taps run with clean water (or sometimes don't!) to how we can build strong and safe structures.

Lesson notes

2. 1. States of Matter Everything around us is made of matter.

Matter exists in three common states: solid, liquid, and gas.

Solid: A solid has a definite shape and a definite volume. The particles (tiny pieces) that make up a solid are packed tightly together and do not move around freely. Examples of solids in South Africa include rocks, bricks, wood, and ice (when it's cold enough!). Think about your school desk – it's a solid.

Liquid: A liquid has a definite volume but no definite shape. It takes the shape of its container. The particles in a liquid are closer together than in a gas, but they can move around and slide past each other. Examples of liquids include water, milk, juice, and petrol. Think about a glass of orange juice – it's a liquid.

Gas: A gas has no definite shape and no definite volume. It expands to fill the space available. The particles in a gas are far apart and move around randomly. Examples of gases include air, oxygen, and steam. The air we breathe is a mixture of gases.

Changes of State: Matter can change from one state to another by heating or cooling.

Melting: When a solid is heated, it can change into a liquid. For example, ice melts into water when it gets warm. Think about ice cream melting on a hot South African day!

Freezing: When a liquid is cooled, it can change into a solid. For example, water freezes into ice when it gets very cold.

Evaporation: When a liquid is heated, it can change into a gas. For example, water evaporates into steam when it boils. Think about how puddles disappear after a rain shower on a sunny day – that's evaporation.

Condensation: When a gas is cooled, it can change into a liquid. For example, steam condenses into water droplets on a cold surface. Think about the mist that forms on your bathroom mirror after a hot shower. 2.

2. Properties of Materials Different materials have different properties, which make them suitable for different uses.

Some important properties include: Strength: How well a material can resist being broken or bent. Steel is very strong, making it useful for building bridges and buildings. Clay bricks are used to build houses because they are strong and durable.

Flexibility: How easily a material can be bent without breaking. Rubber is very flexible, making it useful for making tires.

Absorbency: How well a material can soak up liquids. A sponge is very absorbent, making it useful for cleaning up spills. Cotton is used to make towels because it is absorbent.

Waterproof: The ability of a material to repel water. Plastic is waterproof, making it useful for making raincoats.

Transparency: The ability of a material to allow light to pass through it. Glass is transparent, making it useful for making windows. Think about building a shack – you wouldn't use glass (not strong enough), you might use corrugated iron (strong and waterproof) and wood (strong and available). 2.3 Water Sources and Water Conservation South Africa is a water-scarce country. It is important to know where our water comes from and how to conserve it.

Water Sources: Rain: Rainwater is the primary source of all water.

Rivers: Rivers carry water from higher ground to lower ground. Many communities in South Africa depend on rivers for their water supply.

Examples: Orange River, Limpopo River.

Dams: Dams store water for later use. Dams are important for irrigation, drinking water, and generating electricity.

Examples: Gariep Dam, Vaal Dam.

Groundwater: Water that is stored underground in aquifers. Boreholes are drilled to access groundwater.

Springs: Natural sources of groundwater that flow to the surface.

Water Conservation: Saving water is crucial for everyone in South Africa.

Here are some ways to save water: Take shorter showers. Fix leaky taps and pipes. Use a bucket to wash your car instead of a hose. Water your garden early in the morning or late in the evening to reduce evaporation. Collect rainwater for watering your garden. Don't leave the tap running while brushing your teeth. Guided Practice (With Solutions)

Question 1: Name one example of a solid, a liquid, and a gas that you might find in your home in South Africa.

Solution: Solid: A brick (if your house is made of bricks), a table, or a book.

Liquid: Water from the tap, milk, or cooking oil.

Gas: The air we breathe, or the gas used for cooking (if you have a gas stove).

Commentary: This question reinforces the understanding of the three states of matter by asking for everyday examples.

Question 2: Explain what happens to an ice cube when you leave it out in the sun on a hot day. What is this process called?

Solution: The ice cube will melt. As the sun heats the ice cube, it changes from a solid (ice) to a liquid (water). This process is called melting.

Commentary: This question tests the understanding of changes of state, specifically melting, and relates it to a common experience.

Question 3: A farmer needs to build a dam. Which property of concrete makes it a suitable material for building dams? Why?