You should spend about 20 minutes on this task.
The following are two filter systems. Summarise the information by selecting and reporting the main features, and make comparisons where relevant. Write at least 150 words.
Write at least 150 words.
Model Answer
The given process compares the steps of purifying water by two types of filter systems. It is clear from the graph that the basic principal of purifying water in both systems is filtration.
In the first system there is a 200 litre water container which has an inlet on the top through which dirty water is sent in. The top one third has sand to filter the water. Below the sand are tiny stones and below the layer of stones are pipes with holes. After passing through the three layers the water which comes out is pure and fit for drinking.
The second system is a bit more advanced. The untreated water is stored in a container which has a tap and from that container the water is sent to another container with sand. After being filtered through the sand the water is again stored in another container with a tap from which the water is finally used for household purposes.
So, it can be seen that water can be purified for household use using a very simple and inexpensive method of filtration.