Cambridge Lower Secondary Science –
Stage 8 Teaching Pack
Topic: Dissolving, Solutions, Solubility and Paper Chromatography
Suggested Grade: 7
Learning Objectives
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Define solute, solvent and solution.
Explain dissolving using particle ideas.
Describe solubility and saturated solutions.
Plan and carry out a solubility investigation.
Use paper chromatography to separate mixtures.
Key Vocabulary
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Solute
Solvent
Solution
Solubility
Saturated solution
Chromatography
Pigment
Lesson Plan Overview
Lesson 1: Dissolving and solutions
Lesson 2: Solubility and factors affecting dissolving
Lesson 3: Planning a solubility investigation
Lesson 4: Paper chromatography practical
Activity: Testing Solubility
Materials: salt, sugar, sand, flour, water, beakers, stirring rods
Students test which substances dissolve and record results in a table.
Student Worksheet Questions
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Define solute, solvent and solution.
Give two examples of soluble substances.
What is a saturated solution?
Explain why sugar dissolves faster in hot water.
Describe one use of chromatography.
Practical Investigation Planning Sheet
Aim: Investigate which substance has the highest solubility in water.
Independent variable: type of solute
Dependent variable: amount dissolved
Controlled variables: temperature, volume of water
Checkpoint Test (25 marks)
6. Define solute, solvent and solution. (3 marks)
7. Explain what happens when a substance dissolves in water. (3 marks)
8. State two factors that affect dissolving. (2 marks)
9. Describe how to perform a paper chromatography experiment. (5 marks)
10. A student tests dissolving at different temperatures. Identify independent and
dependent variables. (4 marks)
11. Explain why different colours move different distances in chromatography. (4 marks)
12. Draw and label a chromatography setup. (4 marks)
Mark Scheme (Sample)
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Solute – substance that dissolves
Solvent – liquid that dissolves solute
Solution – mixture formed
Chromatography explanation – separation because substances move at different speeds
Assessment Rubric
Criteria
Excellent
Good
Needs Improvement
Concept
understanding
Clear explanation
Minor errors
Limited
understanding
Investigation
planning
Correct variables
and method
Mostly correct
Incomplete plan
Scientific
vocabulary
Correct terms used
Some terms
Few correct terms