Band 8.5 IELTS Writing Task 1 Model Answer

Overall Band Score: 8.5 · Cambridge IELTS 21 · 2026-08-18

IELTS Writing Task 1 question

The diagram below shows how one type of desert, known as a rain-shadow desert, is formed.

Summarise the information by selecting and reporting the main features, and make comparisons where relevant.

The formation of rain-shadow deserts

Student answer (Band 8.5)

The diagram illustrates the process by which a rain-shadow desert is formed when moist air passes over a mountain range.

Overall, the formation of a rain-shadow desert involves several stages. Moist air from the ocean is forced upwards as it encounters a mountain, resulting in rainfall on the windward side. As the air moves over the mountain and descends on the opposite side, it becomes increasingly warm and dry, creating arid conditions that eventually lead to the formation of a desert.

Initially, moisture-laden air moves inland from the ocean towards a mountain range. As this air reaches the windward side of the mountains, it is forced to rise. The higher the air rises, the cooler it becomes, causing the water vapour to condense and form clouds. Consequently, substantial rainfall occurs on the windward slope, resulting in relatively wet conditions and supporting vegetation in this area.

After crossing the mountain peak, the now drier air begins to descend on the leeward side. As it moves downwards, it becomes warmer, which reduces its relative humidity and prevents significant cloud formation. Therefore, very little precipitation occurs on this side of the mountain.

Eventually, the persistent lack of rainfall creates a dry region known as a rain-shadow. Over time, these extremely arid conditions result in the development of a desert on the leeward side of the mountain range. Thus, the contrast between the wet windward slope and the dry leeward side is the key feature of the rain-shadow effect.

AI examiner evaluation

Task Achievement / Task Response — Band 8.5

The response is excellent. You have clearly identified the main stages of the rain-shadow desert formation process, from the initial moisture-laden air movement to the final arid conditions on the leeward side. The overview is well-crafted, effectively summarising the core mechanism. You have successfully highlighted the contrast between the windward and leeward sides, which is the central feature of the diagram. The information is accurate, logically sequenced, and fully addresses the prompt requirements without any omissions.

Coherence and Cohesion — Band 8.5

The essay is highly coherent. Each paragraph has a clear focus, and the progression of ideas is logical, following the natural sequence of the process. You use a variety of cohesive devices such as 'Consequently', 'After crossing', and 'Therefore' to link ideas smoothly. Paragraphing is used effectively to separate the different stages of the process, making the text very easy to follow. The transition between the windward and leeward descriptions is particularly well-managed.

Lexical Resource — Band 8.0

You demonstrate a wide and precise range of vocabulary appropriate for a technical description. Terms such as 'moisture-laden', 'condense', 'leeward', 'windward', and 'arid' are used accurately and naturally. The language is sophisticated and contributes to a professional tone. There are no noticeable errors in word choice or collocation, and the vocabulary is well-suited to the task of describing a scientific process.

Grammatical Range and Accuracy — Band 8.0

The grammatical control is very strong. You use a variety of complex sentence structures, such as 'The higher the air rises, the cooler it becomes' and 'As the air moves over the mountain and descends on the opposite side, it becomes increasingly warm and dry'. Punctuation is accurate throughout, and the majority of sentences are error-free. The flow of the text is natural, and the grammatical structures effectively support the clarity of the explanation.

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