Ecosystems 13

Year 10 Topic 2 – Learning Opportunity 13: Desalination
This learning opportunity has 6 tasks to complete.
Target time: 50 minutes.

By the end of this learning opportunity you will be able to: explain the importance of the water cycle, including the processes involved and the production of potable water in areas of drought, including desalination.

Key words: desalination, drought, precipitation, potable water, distillation.

Task 1: Define these key words. Watch the video to help you.

Evaporation –
Condensation –

Potable water is _______ to drink. Most countries use _______________ to produce potable water. In some areas of the world where it is hot and dry there may be drought. These countries can use desalination to produce potable water. Desalination is the production of potable water from ________ water, usually using the process of _____________.

Find the answers at the end of the blog.

Task 2: Label the diagram to recap the process of distillation.

Bunsen burner, clean (potable) water, Liebig condenser, liquid water, steam, steam, thermometer, water in, water out, salt solution.

Find the answers at the end of the blog.

Task 3: Put these steps in order to explain how distillation can be used to produce potable water in a village that is close to the sea.

• The salt and other impurities are left behind in the salty water.
• Salty water is heated until the water evaporates forming steam.
• The steam is condensed in another container to give pure water.

Find the answers at the end of the blog.

Task 4: Write 2 bullet points to describe the process of reverse osmosis. Use the diagram and the video from task 1 to help.

File:Reverse osmosis.png - Wikimedia Commons

Find the answers at the end of the blog.

Task 1: Answers

Evaporation – the change of state from liquid to gas.
Condensation – the change of state from gas to liquid.
Potable water is safe to drink. Most countries use precipitation to produce potable water. In some areas of the world where it is hot and dry there may be drought. These countries can use desalination to produce potable water. Desalination is the production of potable water from salty/sea water, usually using the process of distillation.

Task 2: Answers

Task 3: Answers

• Salty water is heated until the water evaporates forming steam.
• The salt and other impurities are left behind in the salty water.
• The steam is condensed in another container to give pure water.

Task 4: Answers

Water is put under high pressure and passed through a membrane which has tiny pores (holes) in it.
The pores allow water molecules through, but prevents salt molecules from passing through.

Task 4: Complete the quiz using the link below.

Quiz

Challenge Task: Complete the exam question.

Challenge Task: Answers

End of Learning Opportunity 13