The diagram below shows how a simple water filter is constructed and how it functions to produce clean drinking water.
Sample Response
The diagram gives information about the structure and operation of a water filter designed to produce drinking waterwhose purpose is to ensure the production of drinkable water.
Overall, the water-purifying process makes use of two connected containersbasic equipment and relies on the filteringnatural 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 of a black pipeby means a black pipe.
As for the working mechanism, at the beginning of the process, untreated water is poured into the container, where the filtration phasefiltering phrase directly takes place. The water passes through the layers of sand, charcoal, and gravel in sequencein chronological order, and during this stage, the contaminants from the impure water are captured within these layers, thereby removing impuritiesfacilitating the elimination of impurities from the water. The process continues as the filtered water is transferredcontinues with transferring the filtered water into a separate storage tank, where the clean water can be stored and used for human consumption.
Why this response received Band 8.0
The response gives a clear, well-sequenced account of both the filter’s construction and its operation, and it identifies the three filtering layers accurately. The main limitation is that some visible components, especially the storage tank’s tap and the containers’ lids, are omitted, while a few awkward expressions reduce precision. Add those structural details and replace imprecise phrases with straightforward process language.
IELTS Writing Criteria Scores
Task Achievement
The construction, material order, flow of water, and storage stage are accurately explained, with only minor visible components omitted.
Include the tap and lids to make the account of how the complete apparatus is constructed and used fully comprehensive.
Coherence and Cohesion
The response follows a clear progression from overview to equipment and then operation, with cohesive links supporting an easy-to-follow sequence.
Keep each stage concise and avoid repeating the removal of impurities once the filtering function has already been established.
Lexical Resource
Vocabulary is varied and generally precise for describing construction and filtration, though “filtering phrase” and “chronological order” are inappropriate choices.
Replace awkward terms with precise process language such as “filtration stage” and “in sequence.”
Grammatical Range and Accuracy
A wide range of complex sentences is handled accurately, with only isolated problems in phrases such as “by means a black pipe.”
Proofread prepositional patterns and verb complements, especially “by means of” and constructions following “continues.”
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IELTS Academic Writing Task 1
The diagram below shows how a simple water filter is constructed and how it functions to produce clean drinking water.
Your response
Write the task yourself, then compare your choices with the annotated response.