The diagram below shows how a simple water filter is constructed and how it functions to produce clean drinking water.
Summarise the information by selecting and reporting the main features, and make comparisons where relevant.
» Write at least 150 words.
Model Answer 1:
The diagram gives information about the structure and operation of a water filter whose purpose is to ensure the production of drinkable water.
Overall, the water-purifying process makes use of basic equipment and relies on the natural properties of three different materials to filter the impure water.
Regarding equipment, the bottom half of the first container is made up of three essential layers, which are sand, charcoal and gravel. In particular, the layer at the base is gravel, on top of which are layers of charcoal and sand, and their functions are to remove any contaminants from the impure water, allowing it to be purified. This filtering container is connected to a storage tank for storing drinking water by means a black pipe.
As for the working mechanism, at the beginning of the process, untreated water is poured into the container, where the filtering phrase directly takes place. The water passes through the layers of sand, charcoal, and gravel in chronological order, and during this stage, the contaminants from the impure water are captured within these layers, facilitating the elimination of impurities from the water. The process continues with transferring the filtered water into a separate storage tank, where the clean water can be stored and used for human consumption.
(208 words)
Model Answer 2:
The provided diagram illustrates the straightforward process by which water is filtered. Overall, the process employs uncomplicated equipment and relies on the natural properties of different materials to remove impurities from water.
Regarding the equipment and ingredients, the key components necessary for this method are a sizable container and three essential ingredients namely sand, charcoal, and gravel. These elements are arranged in layers, designed to progressively remove contaminants. Specifically, the bottom layer is gravel, on top of which is a layer of clean sand and then another layer of crushed charcoal.
The process begins when untreated water is poured into the container and undergoes a filtering phase. During this stage, water passes through the layers, with larger debris being trapped in the gravel, followed by smaller particles being trapped in the sand, and some contaminants being absorbed by the charcoal.
After successfully passing through all three layers, the water emerges filtered and purified, now ready for drinking. Subsequently, a pipe is affixed to the container so as to transfer the filtered water into a separate storage tank, where it remains available for utilization whenever required.
(185 words)
