Why diagrams help explanations

TL;DR:

• Pictures and words together give you two ways to hold an idea, which is why drawings help so much.

• A drawing lets you point, so the explanation can say "this" and "here" instead of describing positions.

• Keep diagrams simple: they should carry the idea, not decorate it.

Try explaining to a friend how a seesaw works using only words. "The heavier person has to sit closer to the middle, and the lighter person further out, so that the two sides balance." It is accurate, and you have to hold a lot in your head to follow it. Now draw a line, a triangle in the middle, and two stick figures. Suddenly it is easy.

This is more than a feeling. There are good reasons a drawing helps, and good ways to use one.

Two channels are better than one

Psychologists describe an idea called dual coding: when you take in an idea as both a picture and words, you store it in two forms, and either can help you recall it later. A word description alone leaves only one route back to the idea. A picture with a caption gives you two.

There is a second benefit. A drawing keeps the layout on the page, so you do not have to hold it in memory. That frees up your attention for the actual thinking.

Walk-through: explaining a lever with and without a sketch

The problem: a child of mass 30 kg sits 2 m from the pivot of a seesaw. Where must a 20 kg child sit on the other side to balance?

Words only

"The turning effect of each person is their weight times their distance from the pivot. For balance, those must be equal on both sides. So thirty times two equals twenty times the distance, which gives three metres." It is correct. But you had to hold "which side", "which weight" and "which distance" in mind while listening.

With a sketch

1. Draw the beam: A horizontal line with a small triangle under the middle. Mark the triangle "pivot".

2. Add the children: On the left, label 30 kg at 2 m from the pivot. On the right, label 20 kg at an unknown distance d.

3. Mark the turning effects: Under each child write weight × distance. Left: 30 × 2 = 60. Right: 20 × d.

4. Balance them: Set the two equal: 20 × d = 60, so d = 3 m.

5. Check: Right side: 20 × 3 = 60. Left side: 30 × 2 = 60. Equal, so the beam balances.

The sketch did not add facts. It put the facts where you can see them. Notice how the heavier child ends up closer to the pivot on the drawing: you can see the answer is plausible before you even calculate.

Pointing

A big advantage of a drawing is that you can point at it. "This distance" is clearer than "the distance from the pivot to the centre of the child on the left". Pointing turns a long description into a single word. When you are listening to an explanation, a pointing hand or cursor does the same job.

Less text, more thinking

• Words are good for reasons, rules and names.

• Pictures are good for layout, shape, direction and comparison.

• Together, each does what it is best at, and the text can be much shorter.

Diagrams also help the person doing the explaining. Drawing forces you to decide what to put where, which exposes the parts of the idea you were glossing over. It is common to find you understand a topic properly only after you have to draw it. The same applies when you are the learner explaining it back, and it is one more reason to sketch even when you think you already get it.

With a screen-aware helper, the drawing can go straight onto the thing you are looking at, so the arrow lands on the exact line of your own homework instead of on a generic picture.

What makes a good diagram

1. One idea. Draw only what the idea needs. Extra detail steals attention.

2. Labels where they matter. Put names and numbers next to the thing they describe.

3. Built up in steps. Add parts as you explain them, instead of showing everything at once.

4. Yours. A rough sketch you drew yourself often teaches you more than a polished one you copied.

Tip: Drawing something yourself is a test of understanding. If you cannot sketch the idea, there is a gap worth finding.

When a diagram does not help

Not every idea needs a picture. A diagram that is cluttered, decorative or mismatched to the point can make things worse. If the sketch makes you ask "what am I looking at?", simplify it or go back to words.

Privacy and control

DuckyHelper can see your screen and draw on it, and it works things out with you on the blackboard. It looks only while the pill is open and for that answer.

Try it yourself

Pick something you recently learned and explain it out loud to yourself without a drawing. Then draw it and explain it again. Notice where the picture saved you words, and where you got stuck without one.

Frequently asked questions

Do I need to draw well?

No. Boxes, lines, arrows and labels are enough.

Is it better to use a picture someone else made?

Both help. Making your own tends to improve your understanding the most.

Can too many pictures hurt?

Yes. Cluttered diagrams distract. Keep each one to a single idea.