Flowcharts

Example: Identifying an Unknown Solution

  flowchart TD
    A[Unknown Solution] --> B{Add litmus paper}
    B -->|Turns red| C[Acidic]
    B -->|Turns blue| D[Basic]
    B -->|No change| E{Add phenolphthalein}
    E -->|Turns pink| F[Weakly basic]
    E -->|No change| G[Neutral]
    
    C --> H[Test pH for strength]
    D --> H
    F --> H
    G --> I[Solution identified as neutral]

accTitle: Flowchart for Identifying Unknown Solutions
accDescr: A decision flowchart for identifying whether an unknown solution is acidic, basic, or neutral. Starting with an unknown solution, litmus paper is added. If it turns red, the solution is acidic. If blue, it's basic. If no change occurs, phenolphthalein is added. Pink indicates weakly basic; no change indicates neutral.

Guidelines for Describing Flowcharts

Start with an overview

Begin with a brief overview. Describe distinct elements, decision points and start and end points.

Follow the logical flow

Describe methodically from start to finish, top to bottom, or left to right.

Combine with other alternatives.

Simple flowcharts can be converted into nested lists with good results. Present the “shapes” as numbers and the possible transitions as sub-bullets.

For more complex or verbose processes consider expanding the list method into a page outline with headings. This enables the use of links to other headings.

Alternative Format Options

Numbered lists work well for linear processes with decision branches as sub-items.

Start with unknown solution
Add litmus paper to the solution
- If paper turns red → solution is acidic (go to step 5)
- If paper turns blue → solution is basic (go to step 5)
- If no color change → continue to step 3
Add phenolphthalein indicator
- If solution turns pink → solution is weakly basic (go to step 5)
- If no color change → solution is neutral (end)
Solution identified as neutral
Test pH to determine acid/base strength

Text description captures the overall process.

This flowchart shows a procedure for identifying whether an unknown solution is acidic, basic, or neutral. First, litmus paper is added to the solution. If the paper turns red, the solution is acidic; if blue, it’s basic. If there’s no color change, a second test with phenolphthalein is performed. A pink color indicates a weakly basic solution, while no change confirms the solution is neutral. Acidic and basic solutions proceed to pH testing to determine strength.

Common Mistakes to Avoid

Describing shapes — “The diamond shape” means nothing; describe the decision it represents
Ignoring branches — Every path must be described, including what happens at each decision
Losing the sequence — Maintain clear order so readers can follow the logic

For complex flowcharts with many branches, consider using a separate page with headings to represent the structure.

Where to Place the Description

Give the description a heading and reference it in the alt text, or otherwise make sure the relationship between the description and image is clear. If the description is placed at the end of the document use #heading reference links to move back and forth.

This article is an adaptation of ‘Complex Images for All Learners’ by Supada Amornchat, used under CC BY-NC-SA 4.0.

Diagrams Illustrations