A mixture consists of two or more different substances/materials mixed together.
In some mixtures, the different substances are still clearly visible after mixing. The substances in such mixtures can be separated by physical means such as sieving, filtering, hand sorting, setting and decanting.
Teacher Input 1
Greet the learners.
Ask the learners who of them drink coffee.
Ask them to explain how they made the coffee: What ingredients did they have to put together to make a perfect cup of coffee.
Answer: Hot water, coffee powder, sugar, milk, etc.
Ask learners if they know what we call a substance that consists of different materials that have been mixed together.
Answer: A mixture.
Ask learners: Who can give a definition of a mixture?
Answer: A mixture is two or more different materials that have been mixed together.
Present an overview of mixtures of materials by using PRESENTATION 1: Mixtures (1)
When you ask learners to give examples of mixtures in which the different substances are still clearly visible, have examples to show the class.
Reveal the different examples:
peanuts and raisins
different coloured or types of sweets
sugar and cinnamon mix
water and oil (e.g. foam bath and bath oil mixture)
Use PRESENTATION 1: Mixtures (1) to ask learners how they would separate different mixtures.
Learner Activity 1
This is a practical activity.
Acquire and prepare the following materials in advance:
bag of split peas or dried beans
bag of rice
small packet of sugar
clean white sand
plastic spoons for scooping
paper cups for mixing
Guide learners as they follow the instructions and complete WORKSHEET A: Making Mixtures – Solids.
Explain to learners how this worksheet will be assessed.
Teacher to use WORKSHEET A: Memorandum to mark the learners’ work.
Teacher Input 2
Tell learners that we have now mixed solid materials.
The ingredients we mixed had different sized grains.
Ask learners: What did you learn from this?
Answers can include:
when the grains are large enough, we can separate them by hand;
when the grains are of different sizes, we can use a sieve (sifting) to separate them.