Insoluble substances

• Some solids will not form a solution in water (insoluble solids).

• Tell learners that they have now learnt that some substances are soluble and others are not (insoluble).
• Ask the learners what their mothers or sisters use to remove nail polish from their nails.

Answer:  Nail polish remover or thinners.

• Is it possible to remove your nail polish with water? Why not?

Answer:  Nail polish is not soluble in water.

• Can the learners think of any other examples?

Answers can include:  We can clean a paintbrush in water if we used a water-based paint.  If we used an oil-based paint, the paint will not be soluble in water, so we would need to use thinners.

• Show VIDEO CLIP 8: Soluble And Insoluble Substance Why Does Salt Dissolve in Water But Not Oil Extra marks (2:24 min.). 
• Present an overview of this topic by using PRESENTATION 4: Insoluble substances.

• Learners complete WORKSHEET F: Solutions and special mixtures: Word search.
• Guide the learners on how to undertake this activity by providing examples and explaining how this worksheet will be assessed.

Teacher to use WORKSHEET F: Memorandum to mark the learners’ work

• Learners complete Quizzes 1 and 2.
• Teacher to support learners as they undertake each quiz.
• Teacher to explain how these quizzes will be assessed.
• Teacher to use QUIZ 1 and 2: Memoranda to mark the learners’ work.