Soluble solids (solutes) can dissolve in water (solvent).
The substances in solutions cannot be separated by sieving, filtering, hand sorting, settling or decanting.
Some solutes can be recovered (separated) by evaporating the solvent (such as recovering salt from sea water).
When substances dissolve, solute particles become dispersed in the spaces between the solvent particles.
Teacher Input 3
Ask learners if they can guess what a soluble substance is.
Answer: A soluble substance will form a solution when it is mixed with water.
Ask learners to give examples of soluble
Answers could include: sugar, salt, etc.
Are the learners able to guess what an insoluble substance is?
Answer: It is a substance that does not form a solution when mixed with water.
Ask learners to give examples of insoluble
Answers could include: sand, mealie meal, curry powder, custard powder, etc.
Present an overview of key terms used when talking about soluble substances by using PRESENTATION 2: Soluble substances.
Learner Activity 2
Learners complete the practical activity in WORKSHEET B: Soluble and insoluble mixtures.
Explain to the learners how this worksheet will be assessed.
Teacher to use WORKSHEET B: Memorandum to mark the learners’ work.
Teacher Input 4
Ask learners if they can remember what happened when they mixed peas or beans with sugar or sand. Can they remember what happened when they mixed the water and the oil together? Were they able to separate the materials after it was mixed?