Lesson Notes By Weeks and Term v4 - Basic 6

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

• Define matter and identify its various forms.
• Classify matter into elements, compounds, and mixtures.
• Describe the properties of solids, liquids, and gases.
• Provide examples of each type of matter from our surroundings.

Lesson summary

This lesson introduces learners to the concept of mixtures and the practical techniques used to separate them. In our daily lives in Ghana, from the kitchen to industrial processes, we constantly separate mixtures. We separate stones from rice, filter our local drinks like 'asaana' or 'sobolo', and even traditional salt winners separate salt from seawater. Understanding these methods helps us appreciate the science in our everyday activities, encourages critical thinking, and builds foundational skills for future scientific studies. This lesson will be highly practical and hands-on, allowing learners to see science in action.

Lesson notes

A. What is a Mixture? A mixture is a substance made by combining two or more different materials in such a way that no chemical reaction occurs. Each material keeps its own identity and properties. Key Idea: The parts of a mixture can be separated again. Local Examples: *Gari and groundnuts:* You can still see the gari and the groundnuts. You can even pick the groundnuts out. *Sandy water:* A mixture of sand and water. The sand does not disappear or become water. *Salt solution:* A mixture of salt and water. Even though you cannot see the salt, it is still there. If you taste the water, it is salty.

B. Why Do We Separate Mixtures? We separate mixtures for several important reasons: To remove unwanted substances: For example, separating small stones and chaff from rice or beans before cooking to make it safe to eat. To obtain a useful substance: For example, separating pure salt from sea water at the Ada salt pans. To purify a substance: For example, filtering muddy water to get cleaner water for use.

C. Methods of Separating Mixtures Here are the key methods we will learn. Let us explain them one by one. Sieving (or Sifting) What it is: A method used to separate a mixture of solid particles of different sizes. How it works: We use a tool called a sieve. A sieve has tiny holes (called a mesh). When the mixture is poured into the sieve and shaken, the smaller particles fall through the holes, while the larger particles remain in the sieve. Ghanaian Example: Making Gari: After frying the cassava mash, it is sieved to get fine, smooth gari. The larger, lumpy parts are left behind. Baking: A baker sieves flour to remove lumps and make it fine for baking bread or cake. Construction: Sand is sieved at building sites to separate fine sand from gravel and large stones. *Mixture type:* Solid + Solid (different sizes). Decantation What it is: A method to separate an insoluble solid (a solid that does not dissolve) from a liquid by carefully pouring off the liquid. How it works: Sedimentation: First, you allow the mixture to stand without disturbance. The heavier, insoluble solid particles will settle at the bottom. This settled solid is called sediment. Pouring: You then carefully tilt the container and pour the clear liquid on top into another container, leaving the sediment behind. Ghanaian Example: Sand and Water: If you have a bucket of water with sand at the bottom, you can let the sand settle and then carefully pour out the water. Washing Rice: When your mother washes rice, she lets the rice settle and pours off the starchy water. *Mixture type:* Insoluble Solid + Liquid. Filtration What it is: A method used to separate a fine, insoluble solid from a liquid by passing the mixture through a filter. How it works: A filter (like filter paper, a clean cloth, or cotton wool) has very tiny pores. These pores are small enough to let the liquid pass through but are too small for the solid particles. The liquid that passes through is called the filtrate. The solid that is trapped by the filter is called the residue. Ghanaian Example: Making 'Sobolo' or 'Asaana': After boiling the hibiscus leaves or maize, the mixture is poured through a fine mesh cloth or sieve to separate the drink from the solid particles. Purifying Water: In the community, some people use a clean white cloth to filter water from a river or well before drinking. This removes dirt and suspended particles. This is a more effective method than decantation for very fine particles like mud. *Mixture type:* Fine Insoluble Solid + Liquid. Evaporation What it is: A method used to separate a soluble solid (a solid that dissolves, like salt or sugar) from a liquid. How it works: The solution (e.g., salt water) is heated. The liquid (water) gets hot, turns into a gas (water vapour), and escapes into the air. This process is called evaporation. The dissolved solid cannot turn into a gas, so it is left behind in the container as crystals. Ghanaian Example: Salt Winning in Ada/Keta: This is a perfect large-scale example. Seawater is collected in large, shallow ponds called pans. The sun heats the water, causing it to evaporate over many days. The salt is left behind and then harvested. *Mixture type:* Soluble Solid + Liquid (a solution). Magnetism (Magnetic Separation) What it is: A method used to separate magnetic materials from non-magnetic materials. How it works: We use a magnet. The magnet will attract and pull the magnetic materials out of the mixture, leaving the non-magnetic ones behind. Magnetic materials: Iron, Steel, Nickel, Cobalt. Non-magnetic materials: Sand, rice, gari, wood, plastic, stone. Ghanaian Example: Removing Nails from Sand: If a carpenter spills iron nails in a pile of sand, the easiest way to get them back is to run a magnet through the sand. Scrap Yards: At a scrap metal yard (like Agbogbloshie in Accra), large electromagnets are used on cranes to lift and separate iron and steel cars and parts from other non-magnetic waste. *Mixture type:* Magnetic Solid + Non-magnetic Solid.

Guided Practice (With Solutions)