Natural Sciences and Technology Grade 6 Term 2: Matter and Materials Solutions as special mixtures

Topic 3 Solutions as special mixtures Gr 6 Natural Sciences and Technology – Term 2, Topic 3

What is a mixture? A mixture consists of at least two different materials mixed together. In some mixtures the different substances are still clearly visible after mixing. In others, especially mixing of liquids, it is difficult to see the original materials. This is a reminder of the key concepts taught in your previous lesson Gr 6 Natural Sciences and Technology – Term 2, Topic 3

When is a mixture a solution? - If you stir sugar into your tea, can you still see the sugar when you drink your tea? - Is this a solution? - What about when salt is mixed with water? Allow learners opportunity to consider this question. Gr 6 Natural Sciences and Technology – Term 2, Topic 3

When is a mixture a solution? When two or more substances mix together and you cannot identify the different substances. E.g.: sugar and water. Mixture Any two substances mixed together. E.g.: peanuts and raisins; sugar and water. It is important that learners realise that the mixture of sugar and water is a solution. Gr 6 Natural Sciences and Technology – Term 2, Topic 3

Solution In a solution one or more substances are dissolved together. Gr 6 Natural Sciences and Technology – Term 2, Topic 3

What does dissolve mean? when the particles of one substance become broken up and spread between the particles of another substance; the particles of the one substance seem to disappear into something else; Example: when sugar is dissolved into water; This is different from melting, which is the result of heating one material to change its state. The information about melting is taken directly from CAPS, page 53 Gr 6 Natural Sciences and Technology – Term 2, Topic 3

Solutions solids dissolved in liquids; gasses dissolved in liquids; Solutions can be: solids dissolved in liquids; gasses dissolved in liquids; a mixture of solids and liquids and gasses dissolved together. Solutions cannot be easily separated back to the original materials. Gr 6 Natural Sciences and Technology – Term 2, Topic 3

Solutions The substance that looks as if it has disappeared, is called the solute (e.g. the sugar). The substance that we can still see, is called the solvent (e.g. the tea / water). The solvent and solute together are called the solution. Gr 6 Natural Sciences and Technology – Term 2, Topic 3