Clean water

• a clean supply of water is important for people, plants and animals
• water can be cleaned by processes such as sieving, filtering, settling, decanting and adding chemicals to kill germs
• municipal water is cleaned before and after we use it

• Greet the learners.
• Ask them what they can remember from the previous lessons on water pollution and importance of
• To revise this work in a fun way, you may write key words on big pieces of paper and place these upside down on the table. Learners can draw words at random and then the class must come up with any ideas they can remember about the word from the previous lesson.  The following are suggested:
  • waterlogged soil
  • flood water
  • soluble substances
  • insoluble substances
  • water pollution
  • living germs
  • wetlands are like sponges
  • dambos (the word used to describe wetlands in some African countries)

• Show VIDEO CLIP 1: Water Song for Kids (1:35 min.).
• Play the video clip again and encourage learners to sing along.
• After everyone has joined in the singing of the Water Song, divide the class into groups and ask each group to create movements and dance steps to accompany the song.
• After 15 minutes have each group demonstrate their version of the song to the class.

• Prepare the following props beforehand –
  • bottle of clear water
  • bottle of “soiled” water – clear water with a teaspoon of coffee or hot chocolate granules added
• Ask the children which bottle they think contains water that is safe to drink.
• Ask learners why they think the “soiled” water in the bottle is not safe to drink.
• Explain that the “soiled” water only seems unsafe, but that it actually contains a coffee (or chocolate) which makes it safe to consume (drink).
• Tell learners that sometimes:
  • Water, might look unsafe, but is safe to drink, and
  • Water might look clean, but has germs which make it unsafe to drink.

• Tell learners that a clean water supply is very important and ask them why they think we need clean water.

Possible answers:  to drink; for cooking

• Explain that clean water is important because –
  • Our bodies are made up of a lot of water.
  • Our bodies produce waste which makes us lose water, for example, we perspire a lot on a hot day.
  • We need to replenish the water in our body by drinking clean water.
• Plants and animals need clean water to grow and be healthy. Plants and animals provide us with food.
• We need clean water in our seas, lakes and rivers because these are very important ecosystems.
• Water is also used for fun, for example, water sports or swimming.
• Show VIDEO CLIP 2: Access to fresh water (1:55 min.).
• Tell learners that we are lucky to still have good water sources in South Africa, but we need to take care of this precious resource. In many other countries, but also in parts of our own country, people have to walk very far to get water.
• Show VIDEO CLIP 3: How can I live if there is no clean water (2:30 min.).

This is a short story about a little girl living Ethiopia and what she needs to do every day to get water to her family. Ask learners:

• How many hours does Aleyka spend each day to get water?
• Is this water clean (i.e. free from contaminates)?
• When does Aleyka do her school homework?
• What have you learnt from this video?

Answers can include: Not to waste water; not to take clean water for granted; to be very careful about how we use our water.

• There are various ways in which we can clean water. In nature, wetlands help to purify water by acting as filtration systems.  Often there are unclean bodies of water that are not suitable for use by humans and animals.  We can use chemicals to help clean this water.
• People can also carry special purification tablets with them when they are in the wilderness. They can use these to purify the water before drinking it.
• Tell learners that we are going to carry out an activity to clean water. We are going to make an apparatus called a “still” which is a water purification device.

• Guide learners as they undertake their water purification investigation (using a still) as required in WORKSHEET A: Investigation – Purifying water in a still.
• Explain how the completed WORKSHEET A will be assessed.
• Support learners as they write down their observations in the worksheet at the end of the investigation.
• Teacher to use WORKSHEET A: Memorandum to mark the learners’ work.

• Present an overview of the different ways in which water can be purified by using PRESENTATION 1: Processes to purify water.
• Tell learners that they will be required to design and build a water filtration system that they could use to purify water, if there is no electricity (to boil water) or chemicals (like bleach).
• Show VIDEO CLIP 4: Experiment 2: Clean dirty water (2:26 min.).

In this video, learners will see how a water filter can be made using everyday recycled materials.

• After watching the video, guide the learners as they complete the information in WORKSHEET B.

• Guide learners as they undertake their water filter investigation (using a water filter funnel) as required in WORKSHEET B: Investigation – Purifying water using a water filter.
• Explain how the completed WORKSHEET B will be assessed.
• Support learners as they write down their observations in the worksheet at the end of the investigation.
• Teacher to use WORKSHEET B: Memorandum to mark the learners’ work.

• Tell the learners that now that they have completed an investigation into a homemade water funnel filter system, they need to use this knowledge to design and build their own water filters.
• Use the Thunderbolt Kids, Natural Science, Grade 6-A, activity on pages 192 – 194 (or http://www.thunderboltkids.co.za/Grade6/02-matter-and-materials/chapter6.html)
• Explain to learners that they are going to design, make and evaluate a simple system to clean dirty water using the specifications given in the Thunderbolt Kids activity.
• If time allows, use the Thirstin’s Water Filtration Lesson (from EPA of USA), to stimulate thought on water filters. https://www3.epa.gov/safewater/kids/flash/flash_filtration.html

• Learners complete the activity as a project in class.
• Learners:
• Should design and build their own simple system to filter dirty water.
• Can adapt the water filter design discussed earlier in this lesson – using recycled materials as much as possible.
• Should plan and draw their design on a piece of paper
• Must build the actual filter as per their design (using recycled materials).
• Should test their water filter and demonstrate the working of the filter to the class.
• Support learners as they undertake this designing activity and explain how their work will be assessed.

• Tell learners that we have now discovered how to purify water through filtering.
• Recap work done up to this point by using PRESENTATION 1: Processes to purify water again. – adapt if we get pictures from Derrick
• We are fortunate to live in a country where the tap water is normally clean enough to drink.
• In many countries, such as India, clean water is very scarce. In Europe, people buy bottled water to drink, because tap water is often not suitable to drink.
• Many of us are fortunate to have a supply of tap water at our homes. This water supply is managed by the municipalities in the different towns.
• Ask learners if they know where tap water comes from. How does it get to our homes?

Answers:  Water comes from a river or dam or sometimes waste water from factories is used.  Water is then cleaned by the municipality through special processes and relayed to our homes through a network of pipes.

• The place where water is purified by the municipality, is called the water treatment plant.
• Present an overview of how municipal water is treated by using PRESENTATION 2: Treatment of municipal water
• Explain to learners that there are five processes in the treatment of water. These processes are-
  • screening
  • sedimentation
  • aeration
  • settling
  • disinfection

• Tell learners that they must see if they can match up the processes of treating municipal water with the correct descriptions in WORKSHEET C: Processes in treatment of water.
• Learners complete WORKSHEET C.
• Support learners as they undertake this activity and explain how their work will be assessed.
• Teacher to use WORKSHEET C: Memorandum to mark the learners’ work.

• Learners complete the word search activity in WORKSHEET D: Processes to purify water word search.
• Guide learners as they undertake this activity and explain how this worksheet will be assessed.
• Teacher to use WORKSHEET D: Memorandum to mark the learners’ work.

• Learners complete QUIZ 1.
• Teacher to support learners as they undertake this quiz.
• Teacher to explain how this quiz will be assessed.
• Teacher to use QUIZ 1: Memorandum to mark the learners’ work.

• Administer end-of-term QUIZ 2: Term 2 Revision.
• Teacher to support learners as they undertake this revision quiz.
• Teacher to explain how this quiz will be assessed.
• Teacher to use QUIZ 2: Memorandum to mark the learners’ work.