New
New
Removing salt from seawater (non-statutory)
I can investigate ways of making seawater safe to drink.
Lesson 11 of 20
New
New
- Year 5
Removing salt from seawater (non-statutory)
I can investigate ways of making seawater safe to drink.
Lesson details
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.
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.
Teacher tip
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
Supervision
Adult supervision required
Licence
This content is © Oak National Academy Limited (2026), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).
Lesson video
Loading...
Prior knowledge starter quiz
6 Questions
Q1.A solid which is soluble in water will in water.
A solid which is soluble in water will in water.
Q2.Which of these materials are soluble in water?
Which of these materials are soluble in water?
sand
soil
Q3.Match the temperatures of water with its state: solid, liquid or gas.
Match the temperatures of water with its state: solid, liquid or gas.
Q4.What is water called in its gas state?
What is water called in its gas state?
ice vapour
water gas
smoke
Q5.When a solution is heated using an oil burner, what process takes place?
When a solution is heated using an oil burner, what process takes place?
condensation
melting
Q6.If you carried out evaporation on a salt solution, what would be left behind?
If you carried out evaporation on a salt solution, what would be left behind?
water
a salt solution
salty water
Assessment exit quiz
6 Questions
Q1.True or false? The water in our seas and oceans contains salt.
True or false? The water in our seas and oceans contains salt.
false
Q2.What process can we use to remove the water from a salt solution?
What process can we use to remove the water from a salt solution?
freezing
melting
dissolving
Q3.What is the name of water in the gas state?
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.
Condensation is when water in the gas state is so that it changes to water in the liquid state.
heated
dissolved
melted
Q5.Scientists and engineers investigate ways of making seawater safe to drink using...
Scientists and engineers investigate ways of making seawater safe to drink using...
soluble and insoluble.
grouping and classifying.
melting and freezing.
Q6.Which of these are tiny living things that must be removed from water to make it safe to drink?
Which of these are tiny living things that must be removed from water to make it safe to drink?
microscopes
microwaves
