Year 7 Science

Matter

Guidance for Teachers and Parents.

Lesson 4 - What's in a Solution?

National Curriculum: Programmes of Study for Sc3

Work on the classification of materials, the ways in which materials can be changed related to pupils' knowledge about particles as constituents of matter.

Key Elements

(a) To draw distinctions between melting and dissolving.

(a) To note that the physical properties of solvents are changed when they become part of a solution.

(c) To consider which separation technique is appropriate for the recovery of a dissolved solid.

(d) Water is not the only solvent.

(e) That fixed volumes of a solvent can only dissolve a certain amount of solid - saturation. This can only be altered by changing the temperature.

(g) Solutions can be visualised as a distribution of solute particles in a solvent.

Objectives

Pupils should:

(a) distinguish between the processes of melting and dissolving in relation to sugar.

(b) distinguish soluble substances from insoluble by experimentation.

(c) separate a dissolved substance from a solution.

Outcomes

Pupils are be able to:

(a) predict that increasing the temperature of a solvent will usually increase the total amount of solid that will dissolve.

(b) represent a solution on a particle level.

(c) use solubility data to produce a graph or bar chart and draw a conclusion.

Notes

Students often do not distinguish between the processes of melting and dissolving. Using the familiar context of sugar at the start the lesson will help resolve this misconception.

The following PowerPoint '95/'97 presentation can be downloaded or viewed online with the appropriate player (download from the Microsoft site).

A Concept Mapping Approach to Solubility.

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