Band 6+: 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.

The diagram shows the water purifying process using only simple construction. Overall, the tools needed are two drums, a pipe, and materials like sand, charcoal, and gravel. The two drums have different functions the first one along with the materials works as a filter and the second one functions only as storage for the cleansed water.

The first drum is filled with multi-layered materials which is consist of sand on the top layer, charcoal in the middle, and gravel placed in the bottom. These materials do the filtering job to transform the polluted water to the clean drinking water. Initially, the water will be pour to the first drum, then it will be infiltrated through the layered materials. The pollutants will be left gradually each time the water passing through from one layer to another layer. In the end, the water transfered by the pipe to the second container.

Compared to the first drum, the second one only plain empty because it only works as storage to contain the cleaned water. The only additional equipment compared to the previous drum is the tap placed in the bottom outside for people to collect the clean drinking water.