Removing salt from seawater (non-statutory)
Lesson details
Learning outcome
I can investigate ways of making seawater safe to drink.
Key learning points
- The water in our seas and oceans contains salt. This water is not safe for drinking.
- Evaporation can be used to remove the water from a salt solution.
- Condensation is when a water in the gas state (water vapour) is cooled so that it changes to water in the liquid state.
- Scientists and engineers investigate ways of making seawater safe to drink using evaporation and condensation.
- Microorganisms must also be removed from water to make it safe to drink.
Keywords
Seawater - Seawater is water from a sea or ocean.
Solution - Some solids dissolve in liquids to form a solution.
Evaporation - Evaporation is the change of state from a liquid to a gas.
Condensation - Condensation is the change of state from a gas to a liquid.
Desalination - Desalination is the process of removing salt from seawater.
Common misconception
Saltwater is safe to drink.
Teaching slides will explain that drinking saltwater can make us ill and will explain the process of desalination.
Teacher tip
Use the guidance in the additional materials document to create a model 'solar still' before the lesson or build as it is explained in the explanation slides, for whole class observations.
Equipment
Desk lamp, large bowl, small bowl / ramekin, recycled plastic bag, elastic band, 200 ml salt solution, 5 coins or other weight.
Content guidance
Risk assessment required - equipment
Risk assessment required - equipment
Supervision
Adult supervision required
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.A solid which is soluble in water will in water.
Q2.Which of these materials are soluble in water?
Q3.Match the temperatures of water with its state: solid, liquid or gas.
solid
liquid
gas
Q4.What is water called in its gas state?
Q5.When a solution is heated using an oil burner, what process takes place?
Q6.If you carried out evaporation on a salt solution, what would be left behind?
Assessment exit quiz
6 Questions
Q1.True or false? The water in our seas and oceans contains salt.
Q2.What process can we use to remove the water from a salt solution?
Q3.What is the name of water in the gas state?
Q4.Condensation is when water in the gas state is so that it changes to water in the liquid state.
Q5.Scientists and engineers investigate ways of making seawater safe to drink using...
Q6.Which of these are tiny living things that must be removed from water to make it safe to drink?
To help you plan your 5 science lesson on: Removing salt from seawater (non-statutory), download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 5 science lesson on: Removing salt from seawater (non-statutory), download all teaching resources for free and adapt to suit your pupils' needs.
The starter quiz will activate and check your pupils' prior knowledge, with versions available both with and without answers in PDF format.
We use learning cycles to break down learning into key concepts or ideas linked to the learning outcome. Each learning cycle features explanations with checks for understanding and practice tasks with feedback. All of this is found in our slide decks, ready for you to download and edit. The practice tasks are also available as printable worksheets and some lessons have additional materials with extra material you might need for teaching the lesson.
The assessment exit quiz will test your pupils' understanding of the key learning points.
Our video is a tool for planning, showing how other teachers might teach the lesson, offering helpful tips, modelled explanations and inspiration for your own delivery in the classroom. Plus, you can set it as homework or revision for pupils and keep their learning on track by sharing an online pupil version of this lesson.
Explore more key stage 2 science lessons from the Properties, changes and separating materials unit, dive into the full primary science curriculum, or learn more about lesson planning.