Diagram label completion


In the IELTS reading diagram label completion task you are given a diagram and have to complete the labels after reading through a given text. This task can be daunting as it is imperative to understand the diagram to complete it.

IELTS Reading diagram label completion sample task

[Note: This is an extract from an Academic Reading passage on the subject of a method of
providing water to grow vegetables in desert regions. The text preceding this extract gave
some background facts about the development of the method.]

Charlie Paton has built a giant structure on a desert island off Abu Dhabi in the Persian
Gulf – the first commercially viable version of his ‘seawater greenhouse’. Local
scientists, working with Paton under a licence from his company Light Works, are
watering the desert and growing vegetables in what is basically a giant dew-making
machine that produces fresh water and cool air from sun and seawater.

The design has three main features. Firstly, there is a front wall of perforated
cardboard through which hot, dry air blows in from the desert. This wall is kept moist
by seawater pumped up from the nearby shoreline. As this water evaporates, heat is
taken from the air inside the greenhouse and moisture added to it. Last June, for
example, when the temperature outside the Abu Dhabi greenhouse was 46 °C, it was in
the low 30s inside and the humidity in the greenhouse was 90 per cent. The cool,
moist air inside the greenhouse allows the plants to grow faster, and because much less
water evaporates from the leaves, their demand for moisture drops dramatically.
Paton’s crops thrived on a single litre of water per square metre per day, compared to 8
litres if they were growing outside.

The second feature also serves to cool the air for the plants. Paton has constructed a
double-layered roof with an outer layer of clear polythene and an inner, coated layer
that reflects infrared light. Visible light can stream through to maximise
photosynthesis, while infrared radiation is trapped in the space between the layers, away
from the plants.

At the back of the greenhouse sits the third element, the main water-production unit.
Just before entering this unit, the humid air of the greenhouse mixes with the hot, dry
air from between the two layers of the roof. This means the air can absorb more
moisture as it passes through a second perforated cardboard wall. Finally, the hot
saturated air hits a condenser. This is kept cool by still more seawater. Drops of pure
distilled water form on the condenser and flow into a tank for irrigating the crops.

The greenhouse more or less runs itself. Sensors switch everything on when the sun
rises, and alter flows of air and seawater through the day in response to changes in
temperature, humidity and sunlight. On windless days, a fan ensures a constant flow of
air through the greenhouse. ‘Once it is tuned to the local environment, you don’t need
anyone there for it to work,’ says Paton. ‘We can run the entire operation off one 13-
amp plug, and in future we could make it entirely independent of the grid, powered
from solar panels.’

Source: Official IELTS website www.https://ielts.org

IELTS reading diagram label completion question

Source: Official IELTS website www.https://ielts.org

IELTS Reading diagram label completion tips

Stay calm even if the diagram looks complicated

The diagram might look complicated, the trick is to stay calm and focus on the strategies shared below to ace these questions.

Understand the diagram before you read the text.

Focus on the diagram and try to understand it before moving to the text.

Avoid wasting too much time on one label

Don’t spend too much time on one label, instead try to complete the easy ones. Re-visit the difficult ones later. This will help you save time and at the same time grab the marks for the ones you attempt.

IELTS Reading diagram label completion strategy

Read the question

Read the question carefully to understand whether you need to use the words from the passage or a list of words given. In this question, you need to use the words given in the passage.

Identify the word limit for answering the question. for this question, there is a word limit of three words specified. Ensure that each label is within this limit else your answer will be marked wrong.

Understand the diagram

Look at the diagram carefully and try to understand what it is trying to convey. Look for clues. for e.g. the heading if the diagram will convey the topic of the diagram. look for other clues in the diagram and other labels.

Skim the text

Skim through the text to understand the meaning of each paragraph and what it tries to convert at a higher level.

Read the text

Read the text in detail and search for answers. Use the answers to fill in the labels.

Correct answers

1 hot, dry air
2 cool, moist air
3 Infrared radiation
4 Condenser
5 Pure distilled water

Work out the answers

As a first step, I read the question carefully and identified that I needed to fill in each label with no more than three words from the given text. Next, I looked at the diagram to identify some clues. for example, the heading of the diagram “The seawater greenhouse” makes it clear that the topic is a greenhouse that uses seawater. The diagram has the various parts of the greenhouse and the multiple steps involved.

Then I skimmed through the given text to understand the high-level meaning of each paragraph or its topic. This helps to identify the paragraph where the answer can be found. This helps to save time as you don’t have to re-read the entire text every time. Finally, I searched for the answers in the relevant paragraphs ensuring the answers didn’t exceed the word limit.

1 The first label is the first step in the seawater greenhouse process. This is what flows from the desert through the cardboard layer into the greenhouse. To look for the answer I went straight to the second paragraph as that is where the process begins. the first sentence of it states that the hot, dry air blows in from the desert through the perforated cardboard. Hot, dry air is the answer.

2 The second label is the step in the process after the hot, dry air passes through the perforated cardboard layer that is kept moist using seawater. This is the step where the hot air changes to cool, moist air. cool, moist air is the correct answer.

3 The third label is about something that comes from the sun but is unable to penetrate the greenhouse. The hint here is that it is not visible light that can penetrate through the roof of the greenhouse. In the extract below you can see the explanation of the double-layered roof which has an inner coated layer that reflects infrared light and lets the visible light stream through. Infrared radiation gets trapped in the layers of the roof. Infrared radiation/light is the correct answer.

4 The fourth label is a part of the greenhouse that is at the rightmost end of the greenhouse. The hint here is that it is part of the water production unit. It is a part after the air has passed through the second perforated cardboard wall. After the air passes the second perforated cardboard wall it hits a condenser where it condenses and becomes water.

Condenser is the correct answer.

5 The fifth label is something that is stored in the tank of the water production unit. As per the extract from the text, it is clear that drops of pure distilled water flow into the tank. Pure distilled water is the correct answer.

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