New
New
Year 10
Edexcel
Higher

Potable water: including sedimentation

I can explain what potable water is and describe how it can be obtained from groundwater and seawater.

New
New
Year 10
Edexcel
Higher

Potable water: including sedimentation

I can explain what potable water is and describe how it can be obtained from groundwater and seawater.

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Lesson details

Key learning points

  1. 'Potable' and 'pure' water are not the same substance.
  2. Water used in analysis must not contain any dissolved ions.
  3. The method used to obtain potable water depends on the water source.
  4. Sedimentation, filtration and chlorination are used to obtain potable water from groundwater and fresh water sources.
  5. Desalination of seawater creates potable water by distillation or reverse osmosis.

Keywords

  • Pure - A single element or compound that is not mixed with any other substance.

  • Potable - Water that is safe to drink.

  • Sterilisation - The process of killing bacteria and other living microorganisms.

  • Desalination - The process of removing dissolved salts from seawater.

  • Reverse osmosis - The movement of solvent through a semipermeable membrane by applying excess pressure on the solution. This process can remove dissolved solutes from water.

Common misconception

Pupils tend to think that all water is the same. Pupils tend to forget that non-visible substances are also found in water.

Stress that pure water only contains H₂O molecules. Other types of water may include varying amounts of dissolved salts, other solids or micro-organisms. Stress that microbes must be killed for water to be potable, but are too difficult to remove.

Create a circus activity about the different types of water (e.g. information posters) and challenge pupils to consider what methods might be used to create potable water from them.
Teacher tip

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

Lesson video

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6 Questions

Q1.
The equipment setup shown below shows which separation technique?
An image in a quiz
decanting
Correct answer: filtration
distillation
chromatography
Q2.
Match each letter on the diagram below to the correct label.
An image in a quiz
Correct Answer:a,filtrate

filtrate

Correct Answer:b,funnel

funnel

Correct Answer:c,filter paper

filter paper

Correct Answer:d,residue

residue

Q3.
A single element or compound that is not mixed with any other substance is said to be .
Correct Answer: pure
Q4.
A substance that dissolves into another substance is described as .
Correct Answer: soluble
Q5.
When a substance dissolves into a liquid (e.g. water), a __________ forms.
suspension
Correct answer: solution
solute
solvent
Q6.
Which of the following techniques can be used to fully isolate components of a mixture or solution?
decanting
Correct answer: filtration
Correct answer: distillation
crystallisation

6 Questions

Q1.
Water is essential for life. Which of the following are domestic uses of water?
watering crops
Correct answer: washing laundry
hydrating farm animals
Correct answer: cooking
Q2.
All sources of water contain varying amounts of micro-organisms and what other material?
insoluble solids
salt
Correct answer: dissolved substances
Q3.
Water that is safe to drink is classified as .
Correct Answer: potable
Q4.
Match each step of making potable water, from either groundwater or freshwater, to the correct description.
Correct Answer:screening,A grid acts like a sieve, removing large insoluble objects.

A grid acts like a sieve, removing large insoluble objects.

Correct Answer:sedimentation,Small, insoluble particles 'settle out', forming a sediment.

Small, insoluble particles 'settle out', forming a sediment.

Correct Answer:filtration,Very small particles are removed by passing through fine layers.

Very small particles are removed by passing through fine layers.

Correct Answer:sterilisation,Microbes are killed.

Microbes are killed.

Q5.
What is used to sterilise a water sample to ensure it is potable?
Correct Answer: chlorine, chlorine gas, Cl, Cl₂
Q6.
Put the following stages of creating potable water from groundwater or freshwater in the correct order.
1 - screening
2 - sedimentation
3 - filtration
4 - sterilisation