IELTS Writing Task – Describing Diagrams – Process Description Part 1

A place where there is a mountain, a sea, and a cloud that is raining

This week’s article is the first of two on process description. This article will focus on the planning, describing diagrams and introduction to writing a process description.

In a process description, they will expect you to write a minimum of 150 words. Describing how something is made or how something works. This will involve explaining one or a series of pictures which illustrate the stages in a process.
The topic can vary; they may ask you, for example, to describe the life-cycle of an insect. Or how people generate electricity. However, this is not a test of your general knowledge and everything you need to know will be in the diagrams.
Firstly, you should make yourself familiar with the assessment criteria.

Task achievement

 You need to write an introduction that paraphrases the question. Also you need to describe the constituent parts of the process. You should divide the body into two or three paragraphs. This should describe each stage of the process in sequence.

Coherence and cohesion


The different stages of the process should be clearly marked by the appropriate use of sequencing expressions. Such as first of allthen and after. Make sure you use articles and pronouns accurately to refer to different elements of the process.

Lexical resource


 You are not expected to explain any technical terms used in the diagram. But the labels in the diagram need to be well-integrated into the model answer. And you should avoid repetition, especially verbs. Language variation is key to scoring a high mark in this section, so try to use some less-common words.

Grammatical range and accuracy


Process description mainly involves using the present simple. You should show good control of subject-verb agreement and active/passive forms. Make sure to use a variety of sentence patterns, mixing simple and complex sentences.
Planning As with all essays, before starting to write make sure you understand what the task is. In the case of process description, this means having a clear idea of what each step describes. And identifying the key language to describe each step. Trying as much as possible to have a different language for each step. One way to check you have fully understood the diagram is to ask yourself questions.
Example 1 The diagram shows how electricity is generated by a hydroelectric dam.

Grammatical range and accuracy Example

As there is only one picture, you need to ask yourself. How am I going to divide this process up (what’s the first step?, what’s the second? etc)?
Are you clear about each of the labels and the link between them? For example, you will probably not know what a “penstock” is but from the diagram it is easy to see that it is basically just a pipe or chamber.
Why have a pipe? What happens to water when you force it through a pipe? This should lead you to think of ‘high pressure’ and so explain how the turbine is moved.
Are you able to refer to all the labels? A particular difficulty with this diagram is knowing how to refer to the ‘river’. You need to notice that from the turbine there are two channels. One flowing into the generator, and the other into the river, allowing the water to be recycled.  
Example 2   The following diagram shows how greenhouse gases trap energy from the Sun.

Grammatical range and accuracy Example –
Again, there is only one diagram here, so you need to ask yourself how you will divide up the task. Why are there two sets of arrows? What is the relationship between them (similarities and/or differences)?
How can you incorporate the bottom left caption referring to the ‘felling of trees?
The diagram’s aim is to show how greenhouse gases are warming the Earth, but it also shows how heat can escape.
How can this contrast be smoothly brought into the essay?   Don’t start writing until you are confident you have fully understood, or as well as you can, the process. The recommend time for this task is Twenty minutes. Spending a few minutes on careful planning is not a waste of time.

The introduction

This should be a paraphrase of the question. And an overview of the process, including reference to the parts that need to explain.
Using the above two examples:

Example 1


The diagram illustrates the basic principles of hydroelectric power. The process requires the construction of a large dam connected to a powerhouse. The dam creates a large reservoir and the powerhouse is where they generate electricity.

Example 2


This diagram explains the role of greenhouse gases in blocking the escape of heat and thus increasing global temperatures. The picture also makes clear how human activity is contributing to this global warming.
Notice that different verbs have been used in the introduction to those used in the title. In example 1 ‘shows become ‘illustrates’, ‘generated’ becomes ‘produced’. And in example 2 ‘shows ‘becomes ‘explains’ and ‘trap’ becomes ‘block’.
But also note that not all the items have been paraphrased. It is a mistake to think that you cannot use any words that are in the title questions. It would be a waste of time to look for ways of paraphrasing ‘hydroelectric dam’ and ‘greenhouse gases’. And other labelled items. Paraphrasing can, and should, involve varying the sentence patterns. As well as looking for synonyms. I hope the above has given you a good idea of how to plan and what to include in your opening paragraph.

The key points are:


Do spend time planning before starting to write.

Make sure you understand what all the labeled or captioned items contribute to the process.
Paraphrase the question in your introduction. But don’t think of this as a sort of game where you must not repeat any of the words in the question.  

If you are serious about taking your IELTS writing to the next level, sign up for your FREE 3 part IELTS writing video course that takes you through both task 1 and task 2. The video lessons are led by our highly experienced UK native IELTS teacher, Katherine. We also provide you with exercises to test your understanding about describing diagrams!

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