An IELTS Writing Task 1 process diagram at Band 6, 7 and 8
Quick answer
This page describes one invented process diagram, the recycling of glass bottles, three times, at Band 6, 7 and 8, with the same overview and the same stages, and it marks the phrases that earn or lose marks. For a process, the thing that most often separates the bands is whether the overview says what the process does as a whole, and whether the stages are linked by more than "then".
In the app, a Task 1 report is marked with a band range for each criterion, and a Data Accuracy card separates a misread diagram from a language mistake.
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On this page
This page takes one invented process diagram and describes it three times, at Band 6, Band 7 and Band 8. The three reports share the same overview and the same stages, so the differences you see belong to the bands, not to the content. How to approach this kind of visual is explained in how to describe process diagrams and maps; the process is a visual type from practice material, and IELTS publishes no list of the diagrams to expect.
The three reports were written for this site. They are not from a real paper, they were not marked by IELTS, and they are illustrations to compare against, not answers to memorise. IELTS.org penalises memorised and plagiarised content, and the diagram in your exam will be different, so the use of this page is to see what each band looks like.
Key takeaways
- All three reports give the same overview and cover the same eight stages. What changes is how well the overview says what the process does, how the stages are joined and how accurately the sentences are built.
- The Band 6 report has an overview and the right stages, but it repeats “then”, adds a reason the diagram does not give and slips on agreement.
- The Band 7 report links the stages with a range of devices and picks out the one stage where new materials enter.
- The Band 8 report is not longer. It folds the stages into fewer, more exact sentences and keeps the passive under control.
The task
This task is invented for practice and is not from a past paper.
The diagram below shows how used glass bottles are recycled into new bottles. Summarise the information by selecting and reporting the main features, and make comparisons where relevant. Write at least 150 words.
The stages, in the order the diagram shows them:
- Used glass bottles are collected from bottle banks.
- Lorries take the bottles to a recycling plant.
- The bottles are sorted by colour on a conveyor belt.
- Magnets and air jets remove the metal caps and labels.
- The clean glass is crushed into small pieces called cullet.
- The cullet is mixed with sand, soda ash and limestone.
- The mixture is heated in a furnace at 1,500°C until it melts, then poured into moulds and blown into bottles.
- The new bottles are cooled slowly, checked for faults and sent to drinks producers to be filled again.
All three reports use this plan:
- Introduction: what the diagram shows, in new words.
- Overview: eight stages in one line, from collection to delivery, with the glass changing from solid to liquid and back to solid, and new materials added at one point only.
- Detail one: stages 1 to 5, ending with the cullet.
- Detail two: stages 6 to 8, from the mixing to the delivery of the new bottles.
The same report at Band 6, 7 and 8
Hover or tap a marked phrase to see what a marker would note. The legend names the criterion for each colour, and orange marks a slip that loses marks.
Band 6
The diagram showSubject-verb agreement: should be “shows” how used glass bottles are recycled into new bottles. Overall, there are eight stages in the process, and it starts with the collection of bottles and finishes with the delivery of new bottlesAn overview is present, with the stage count, the start and the end, but it says nothing about how the glass changes.
First, used bottles are collected from bottle banks, and then they are taken by lorry to a recycling plant. At the plant the bottles is sortedAgreement: should be “are sorted” by colour on a conveyor belt. This is done because the colours recycle better when they are separateA reason the diagram does not give; a report describes the stages and does not explain them. After that, magnets and air jets remove the metal caps and labels from the bottles, and the clean glass is crushed into small pieces called cullet.
Then the cullet is mixed with sand, soda ash and limestoneThird sentence to rely on “then”; the sequence words do not vary. New materials are added only at this stage. The mixture are heatedAgreement: should be “is heated” in a furnace at 1,500°C until it become liquidWord form: should be “becomes liquid”, and the glass is poured into moulds and make into bottlesPassive not carried through: should be “made into bottles”. Finally, the new bottles are cooled slowly and checked for faults, and they are sent to drinks producers to be filled again.
Band 7
The diagram illustrates how used glass bottles are turned into new ones at a recycling plant.
Overall, the process is linear and has eight stages, running from the collection of used bottles to the delivery of new ones, and the glass changes from solid to liquid and back to solid along the wayOverview commits to the stage count, the start, the end and the one change of state.
To begin with, bottles are collected from bottle banks and carried by lorry to the plant. There they are sorted by colour on a conveyor belt, after whichJoins two stages in one sentence instead of repeating “then” magnets and air jets remove the metal caps and labels. The clean glass is crushed into small pieces known as cullet, which is mixed toPreposition slip: should be “mixed with” sand, soda ash and limestone. This is the only stage at which new materials enter the processA key feature picked out and placed where it belongs.
The mixture is then heated in a furnace at 1,500°C until it melts, and the liquid glass is poured into moulds, where it is blown into the shape of bottlesThe natural verb for shaping glass. Once the bottles have cooled slowly, they are checked for faults and sent to drinks producers to be filled againA time clause with a present perfect, followed by a passive main clause.
Band 8
The diagram shows how a recycling plant turns collected glass bottles into new ones.
Overall, the process is a single line of eight stages, from collection to delivery, in which the glass is broken down, melted and reformed, and new materials are added at only one pointOverview gives the stage count, the start, the end, the change in the glass and the one addition.
Used bottles are collected from bottle banks and taken by lorry to the recycling plant, where they are sorted by colour as they travel along a conveyor beltExact and compact: the sorting and its setting in one phrase. Magnets and air jets then strip away the metal caps and labels that remain”Strip away” is exact for removing a surface layer, and “that remain” shows nothing is left, leaving clean glass that is crushed into fragments known as cullet. The first five stages prepare the material, and the last three transform itGroups the eight stages into two blocks, so the paragraphing follows the logic of the process.
The cullet is blended with sand, soda ash and limestone, the only raw materials introduced at any stageThe key feature is kept to a short phrase and does not need its own sentence. This mixture”This” points at one clear thing, the blend just described is heated in a furnace at 1,500°C until it melts. Once molten, the glass is poured into moulds and blown into bottles, which are cooled slowly, inspected for faults and finally despatched to drinks producers for refillingA participle opener, a relative clause and a run of passives kept parallel.
What moved the band
The accounts below follow the public band descriptors, as this site paraphrases them. Each quotation comes from the report of the band named in its sentence.
Task Achievement
The Band 6 report has an overview and covers every stage: “there are eight stages in the process” gives the count, the start and the end. But the overview stops at the count, and the detail adds a reason that the diagram never gives: “This is done because the colours recycle better when they are separate”.
Band 7 makes the summary do more. “the glass changes from solid to liquid and back to solid along the way” tells a reader what the process achieves, and “This is the only stage at which new materials enter the process” picks out the feature worth noticing.
Band 8 puts every feature where it can be found. The overview carries both the change in the glass and the one addition, and the detail then needs only a short phrase, “the only raw materials introduced at any stage”, to restate it. The Task Achievement cell at Band 7 holds the wording this account paraphrases.
Coherence and Cohesion
The Band 6 report is organised and has paragraphs, but its joins are mechanical. “First”, “and then”, “After that”, “Then” and “Finally” are the only ways it moves from stage to stage, and the third sentence in a row begins with “then”.
Band 7 uses devices of different kinds. “after which” joins sorting to the removal of caps inside one sentence, “There” refers back to the plant and “The mixture is then heated” carries the sequence without a new label.
Band 8 needs fewer signposts because the grammar carries the order. “This mixture” points at the blend named a sentence earlier, and “Once molten” joins the melting to the pouring. The Coherence and Cohesion cell at Band 6 describes the mechanical pattern.
Lexical Resource
The Band 6 vocabulary is enough for the diagram, and the attempts at less common wording are not all right: “become liquid” has the wrong word form, and the same passive verbs, “are collected”, “are taken” and “are cooled” fill most sentences.
Band 7 is flexible and mostly exact. “blown into the shape of bottles” is the natural verb for glass, and “known as cullet” introduces the technical term with its label. One slip remains, “mixed to sand”, which needs a different preposition.
Band 8 chooses words because they are accurate. “sorted by colour as they travel along a conveyor belt” holds the sorting and its setting in one phrase, and “finally despatched to drinks producers for refilling” says the last stage in a single phrase. The Lexical Resource cell at Band 8 describes this control.
Grammatical Range and Accuracy
The Band 6 report mixes simple and complex sentences, and its errors are small and repeated: “The diagram show”, “the bottles is sorted” and “The mixture are heated” are agreement slips of the kind that survive a proofread, and “make into bottles” drops the passive.
Band 7 has several kinds of complex sentence and many are clean. “Once the bottles have cooled slowly, they are checked for faults and sent to drinks producers to be filled again” puts a time clause, two passives and an infinitive of purpose in one accurate sentence.
Band 8 widens the range and nearly every sentence is clean. “Once molten, the glass is poured into moulds and blown into bottles, which are cooled slowly, inspected for faults and finally despatched to drinks producers for refilling” opens with a participle phrase and then keeps four passives parallel. Compare the Grammatical Range and Accuracy cell at Band 7.
Traps this task type sets
These come from the process diagrams and maps guide, and each is visible in the Band 6 report.
- Explaining why. The diagram does not say why bottles are sorted by colour. The Band 6 sentence “This is done because the colours recycle better when they are separate” is a guess, and a marker reads it as information that the diagram does not support.
- Repeating “then”. The Band 6 report moves through the middle stages with “then”, “after that” and “then” again. Vary the links, and use a clause such as “after which” or “once” to join stages.
- Losing count of the stages. The overview says eight, so the detail must show eight. Number the stages on the question paper before you write, and check the count against your overview at the end.
- Passives that slip. The passive is the right choice for a process, but it has to be built completely every time. “make into bottles” and “is sorted” show what happens when it is half built under time pressure.
How to use these answers
Write your own report to the same task first, in 20 minutes. Then read the three answers against yours, one paragraph at a time, and ask which band your paragraph resembles on each of the four criteria. Count your own stages before you compare.
Next, mark your own report with the same codes: where your overview says what the process does, where a link joined two stages, where a verb fitted exactly and which slips a marker would circle. Do not memorise any sentence from these pages: IELTS.org penalises memorised content, and the diagram in the exam will not match this one. For the same practice on other visuals, use the Writing Task 1 practice test.
How the app marks it
IELTS Mentor AI marks a Task 1 report with a band range for each of the four criteria, from a strict to a lenient reading, followed by what worked and how to improve for each one. A Data Accuracy card separates a misreading of the visual from a language mistake, and the editor is timed at 20 minutes with a live word count against the 150 minimum.
Where this fits
This page belongs to the process diagrams and maps guide, which explains the approach, and to the Writing test format guide, which covers the whole test. The same exercise is done for a changing place in the map answer at Band 6, 7 and 8 and for combined data in the two charts answer. For how the four criteria combine into a Writing band, see how the IELTS Writing score is calculated, and for the step up to a higher band, the band descriptors explorer.
Frequently asked questions
Are these IELTS Writing Task 1 sample answers from a real paper?
No. They were written for this site, on an invented diagram, and they were not marked by IELTS. The band each one illustrates is the site's reading of the public band descriptors, not a score that any examiner gave.
Does IELTS Writing Task 1 include process diagrams?
IELTS.org's Academic Writing format page lists a diagram of an object, device, process or event as a possible Task 1 visual. It publishes no figures on how often each kind appears, so prepare for charts, processes and maps alike.
Can I memorise the Band 8 answer and use it in the exam?
No. IELTS.org penalises memorised and plagiarised content, and the diagram in your exam will be different, so a learned report would not describe it. Use the three answers to compare with your own writing.
Do I have to use the passive for every stage?
IELTS.org sets no rule on this. The passive suits a process because the diagram cares about what happens to the material, but a mix of structures is what the higher bands reward, so use it where it reads naturally.
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