Describing Process Diagrams

Process diagrams are different from all other Task 1 visuals. Instead of describing data, you describe how something works or how something is made. This requires a different vocabulary set and a different approach. Process diagrams test your ability to write clearly about sequences of steps.

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What Process Diagrams Show

Process diagrams illustrate:

• Manufacturing processes (how cement is made, how chocolate is produced)
• Natural processes (the water cycle, how a volcano erupts)
• Systems (how a power plant generates electricity)
• Life cycles (the stages of a butterfly's development)

They typically include:

• Arrows showing the direction and sequence of steps
• Labels identifying stages, materials, or equipment
• Numbers or letters indicating the order of steps

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Key Differences from Data Visuals

Data visuals (graphs, charts, tables)	Process diagrams
Describe trends and comparisons	Describe steps and stages
Use past tense for past data	Use present simple (processes are general)
Include specific numbers	Rarely include numbers
Use comparative vocabulary	Use sequencing vocabulary
Active voice common	Passive voice essential

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Essential Vocabulary for Process Diagrams

Sequencing Language

Sequencing language by stage

• Beginning: First; Initially; At the first stage; The process begins with/when...
• Middle: Then; Next; After this/that; Subsequently; Following this; At the next stage; Once this is complete; The next step involves...
• End: Finally; Lastly; At the final stage; The process ends with/when...; In the last stage; Ultimately...

Cause and Result

Phrase	Example
which causes / leads to	"...which causes the water to evaporate."
as a result / consequently	"As a result, the mixture solidifies."
this results in / produces	"This produces a fine powder."
in order to / so that	"...in order to remove impurities."
thereby	"...thereby reducing the temperature."

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The Passive Voice

The passive voice is essential for process diagrams because the focus is on the action or object, not on who performs it.

Active vs. Passive

Active	Passive
Workers crush the rocks.	The rocks are crushed.
Machines heat the mixture.	The mixture is heated.
They filter the liquid.	The liquid is filtered.

Common Passive Structures

Present simple passive (most common) — is/are + past participle:

• "The raw materials are collected."
• "The mixture is heated to 1500°C."
• "The product is packaged and distributed."

Passive with "by":

• "The grain is ground by large millstones."
• "The water is filtered by a membrane."
• "The material is transported by conveyor belt."

Passive with "where" (to add location):

• "The liquid is moved to a tank, where it is stored."
• "The mixture enters a furnace, where it is heated."

Band 7+ Tip: Use a mix of active and passive sentences, but the passive should dominate. This is one of the few contexts where heavy passive use is both natural and expected.

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Structure of a Process Diagram Response

Process diagram response structure

1. Introduction — Paraphrase what the diagram shows; state how many stages there are.
2. Overview — Describe the process in general terms; mention the starting point and end point.
3. Body 1 — Describe the first half of the process (steps 1–5).
4. Body 2 — Describe the second half of the process (steps 6–10).

Writing the Introduction

State what the diagram shows and, if possible, how many stages the process has.

Example: "The diagram illustrates the process by which cement is manufactured, from the initial extraction of raw materials to the final packaging of the finished product. The process consists of seven main stages."

Writing the Overview

Summarise the process in general terms. Mention the start and end points and any key transformation.