ISE 5-14 Curriculum Support Materials                                                           Overview advice

Group 9 exemplar Earth & Space  - Water (Word)

1. We take our fairly wet climate for granted and rarely suffer from water shortages. However many businesses are charged for the amount of water they use and so water conservation is an issue for businesses and local authorities. The water coming out of our taps has all been treated to make it safe to drink and so if we use less water then we have to treat less water and so the annual bill we all pay will be less.

In many hot countries water is scarce and water of different types is provided. Desalinated sea water may be provided for things like washing cars, hosing public areas, washing clothes and for showers and baths and special taps marked ‘drinking only’ or ‘potable’ give drinking water from springs.

Encourage the children to imagine what it would be like if their water supply was cut off for a few days - no baths or showers, all water for drinking and cooking to be carried from a stand-pipe or water lorry, no water to flush the toilet etc. Let the children try lifting a bucket of water to see how heavy it is.

Many children will not have been to a reservoir and so it is worth describing it as a big lake which is usually man-made from which water is taken through pipes to a treatment plant where it is made clean enough for us to drink. The points at which water is removed from the reservoir (they usually have towers built on them and are close to a side - usually near to the dam if there is one) act like giant plug holes in an enormous sink.

Could the children imagine what it would be like to be a money spider being sucked down the plug hole? It is very important that they never try to swim in a reservoir since they may find themselves being that money spider.

Water is taken through pipes to the water treatment plant. After allowing the water to stand for a while so that any big particles will settle out, the water passes through a series of filter beds. These are enormous trays containing gravel of different sizes. The water slowly trickles through and any large particles get caught. Useful bacteria build up on the pieces of gravel and they help to remove harmful bacteria which may lurk in the untreated water. From the gravel beds the water is passed over sand filters where smaller and smaller particles are removed from the water until at the end of the filter system the water is clear. As a final precaution chemicals are added to kill any remaining harmful bacteria or viruses and in some areas fluoride is added to help protect the teeth of the people who drink the water.

The children can draw a simple set of pictures to record this process.

To show the children a filter working you can make one in the classroom. The filter bed is made up as shown below. Sources of gravel and sand include garden centres, pet shops, gardens and playgrounds.

Cut the bottom off a lemonade bottle using a Stanley knife and fill with materials as shown. Make up a ‘muddy ‘ water using some soil or similar in water and mixed up. Pour the mixture onto the top of the filter and watch as it works its way through. Have a cup or bowl underneath to catch the filtered water ( the cut off bottom of the lemonade bottle would be ideal).

What has happened to the mud? You will need to find a way of supporting the bottle over the bowl. (Try a string shopping bag or even a strong, clear, plastic bag with the bottom corner snipped off, hung over the back of a chair.)

• having a shower rather than a bath
• collecting rain-water in a butt to use on the garden and to wash the car
• checking for leaking washers in the taps and replacing them if necessary.