What Makes Process Diagrams Different
Unlike graphs and charts, process diagrams have no data to compare and no trends to identify. Your only job is to describe each stage clearly, in order, using sequencing language and the passive voice.
Natural processes (water cycle, life cycles) — use present tense passive: water is evaporated, eggs are laid. Man-made processes (manufacturing, recycling) — also use present tense passive: the material is heated, the product is packaged.
The Structure
Introduction
Paraphrase the diagram title.
The diagram illustrates the stages involved in the production of recycled paper.
Overview
State how many stages there are and give a very brief summary.
State the number of stages, the starting point, and the end point. Example: “Overall, the process consists of seven distinct stages, beginning with the collection of waste paper and culminating in the production of new sheets.”
Body Paragraphs
Split the stages logically — first half in paragraph one, second half in paragraph two.
Essential Sequencing Language
| Stage | Language |
|---|---|
| First | First / Firstly / Initially / To begin with / The process starts when |
| Middle | Next / Then / Subsequently / Following this / After this / Once X has occurred |
| Last | Finally / Lastly / The process concludes with / In the final stage |
The Passive Voice Is Not Optional
Wrong: “Someone heats the water to 100 degrees.” Right: “The water is heated to 100 degrees.”
The agent (who does the action) is irrelevant in process descriptions. Always use passive.
Vocabulary for Common Processes
Manufacturing:
- extracted / processed / refined / assembled / transported / distributed
- heated / cooled / filtered / separated / compressed / shaped / moulded
Natural cycles:
- evaporates / condenses / precipitates / accumulates / absorbs / flows
- hatches / develops / matures / reproduces / migrates
Process diagrams typically need 150–190 words. If you are under 150, you are likely missing stages. If you are over 200, you are probably over-explaining simple steps.
Sample Body Paragraph
In the first stage, used paper is collected from households and offices and transported to a recycling facility. It is then sorted by type before being soaked in large tanks of water. Once the paper has fully dissolved, the resulting pulp is cleaned to remove any ink or contaminants. The cleaned pulp is then spread onto flat screens, where excess water is drained away.
For a process diagram, your writing should read like an instruction manual — precise, ordered, and completely in the passive voice.