Lesson Notes By Weeks and Term v5 - Grade 5
Revision and consolidation of Grade 5 NST topics – Week 3 focus
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Revision and consolidation of Grade 5 NST topics – Week 3 focus
Download the Lessonotes Mobile South Africa app for faster lesson access on Android and iPhone.
Subject: Natural Sciences and Technology
Class: Grade 5
Term: Term 4
Week: 3
Theme: General lesson support
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This week focuses on revising key concepts from the Grade 5 Natural Sciences and Technology curriculum, specifically the topics covered in previous weeks. Revision is crucial because it helps you remember important information and understand it better. Understanding science and technology is important in South Africa because it helps us solve problems related to our environment, health, and economy. For example, understanding how water is cleaned helps us ensure that everyone has access to safe drinking water. Learning about materials and their properties helps us build stronger and safer houses.
2.1 Materials: Natural and Man-Made Materials are what things are made of. They can be natural, meaning they come from the earth (like wood from trees, rocks, and water), or man-made, meaning they are created by people (like plastic, glass, and paper).
Natural Materials: These are found in nature and are not created by humans.
Examples include: Wood: Comes from trees. Used for building houses, furniture, and making paper.
Rock: Found in the earth's crust. Used for building foundations, roads, and monuments. Examples of different kinds of rock are granite, sandstone, and limestone.
Water: Essential for life. Used for drinking, cleaning, and irrigation.
Soil: Supports plant life. Used for farming.
Metals: Found in the earth. Examples include iron, gold, and copper. Used for making tools, jewelry, and electrical wires.
Man-Made Materials: These are created by humans using natural resources.
Examples include: Plastic: Made from oil. Used for making bottles, toys, and packaging. Plastics are often a problem because they don't easily break down and can pollute the environment.
Glass: Made from sand. Used for making windows, bottles, and lenses.
Paper: Made from wood pulp. Used for writing, printing, and packaging.
Concrete: Made from cement, sand, gravel, and water. Used for building houses, roads, and bridges.
Fabric: Made from natural fibers (like cotton or wool) or synthetic fibers (like nylon or polyester). Used for making clothes and blankets.
Properties of Materials: Different materials have different properties that make them suitable for different uses.
Some important properties include: Strength: How well a material can resist being broken or bent. Steel is a strong material used in building bridges.
Flexibility: How easily a material can be bent without breaking. Rubber is a flexible material used in making tires.
Absorbency: How well a material can soak up liquids. Towels are absorbent materials used for drying.
Transparency: How well light can pass through a material. Glass is transparent.
Waterproof: How well a material can prevent water from passing through it. Plastic is often waterproof.
Thermal Conductivity: How well a material conducts heat. Metal conducts heat well, so it's used in pots and pans.
Example: Imagine you want to build a birdhouse. What materials would you use, and why? You might choose wood because it's strong, relatively waterproof (when treated), and easy to work with. You wouldn't use glass because it's brittle and would break easily. 2.2 Mixtures and Separation A mixture is a combination of two or more substances that are physically combined but not chemically bonded. The substances in a mixture keep their own properties.
Examples of mixtures include: Sand and Water: Easy to see the different components.
Salt and Water: The salt dissolves in the water, forming a solution.
Air: A mixture of gases like nitrogen, oxygen, and carbon dioxide.
Dissolving: Dissolving is when a substance (the solute) mixes completely with another substance (the solvent) to form a solution. Salt dissolving in water is a common example. In this case, salt is the solute and water is the solvent. Some substances dissolve more easily than others. Temperature can affect how quickly a substance dissolves; usually, dissolving happens faster in warmer liquids.
Separating Mixtures: Since the substances in a mixture are not chemically bonded, they can be separated using physical methods.
Some common methods include: Filtering: Using a filter (like a coffee filter or a cloth) to separate solid particles from a liquid. For example, filtering sand from water.
Sieving: Using a sieve (a mesh screen) to separate particles of different sizes. For example, separating pebbles from sand. This is important for construction workers.
Evaporation: Heating a solution to evaporate the liquid, leaving the solid behind. For example, obtaining salt from seawater. Many South African communities near the coast use evaporation to get salt.
Using Magnets: Using a magnet to separate magnetic materials (like iron filings) from non-magnetic materials.
Decanting: Carefully pouring off a liquid from a solid that has settled at the bottom of the container. For example, separating water from settled mud.
Example: You have a mixture of sand, salt, and iron filings. How would you separate them? First, use a magnet to remove the iron filings. Then, dissolve the salt in water. Filter the sand from the saltwater. Finally, evaporate the water to get the salt back. 2.3 Simple Machines Simple machines are tools that make work easier by changing the size or direction of the force needed to do work. The six basic types of simple machines are: Lever: A rigid bar that pivots on a fixed point (fulcrum).
Examples: seesaw, crowbar, bottle opener. A lever makes it easier to lift heavy objects by applying force further from the fulcrum.
Wheel and Axle: A wheel that rotates around a rod (axle).
Examples: car wheels, doorknobs, bicycle wheels.