How design quietly shapes society.

Look up from this screen for ten seconds

How many things around you right now were designed by someone? Look at the chair under you, the height of the table, the switch on the wall, the cup beside your hand, the width of the window, and the letters on this page. None of them grew there like a wild tree. Someone chose the material, the height, the colour and the shape. Someone decided who the object would fit, and who would have to stretch or stoop.

Most people think "design" means making things look pretty at the end, like picking a coat of paint or a stylish chair for a magazine cover. That is decoration, not design. Design is how something works for a human being, how it tells you what to do without a manual, and how it behaves when you are tired, in a hurry or carrying a heavy bag.

What does your gut say?

Three quick questions before we begin. There is no score, and nothing leaves this page. At the end of the course you will see your first answers next to what you know by then.

How this course works

Four parts and 26 chapters, then a wrap-up, about 12 hours, at your own pace. Each chapter has:

• an everyday object or scene, something to try, and a question to argue about,
• an "In short" box at the top, so you can see the main points first,
• a link into World 101, Learnacy's map of what the world knows,
• a note for your notebook, and
• a five-question check. Pass it with 4 right, as often as you need.

Pass every chapter check and the final round, and you get a certificate of completion with a link anyone can use to verify it.

Two promises. Every product, app or screen example in this course is either made up and says so, or comes from public and historical design such as road signs, public buildings and standards with sourced facts. We name no brand or app to praise or blame.

One rule for the whole course: questions are more important than answers. Before a good designer draws a single line, they ask: who is this for, what is the real problem, and how will we know if our fix worked?

Explore in World 101

Design sits where art, engineering and human psychology meet. Before you start Chapter 1, open Product, Industrial and Interaction Design in World 101 and look around for five minutes.

The brass handle that lied

You are late for a class. You walk up to a heavy glass door with a long, shiny vertical bar bolted across it. Your hand reaches out, grips the bar and pulls. Nothing moves. You pull harder. Still nothing. A person inside points to a peeling paper label taped at eye level: PUSH. You push the bar, the door swings open, and you walk in feeling clumsy.

Wait a second. Why did you feel clumsy? Were you careless? No. Did your hand do what human hands always do when they see a vertical bar? Yes. Then why did the door refuse to open? Because the door told your hand a lie. Its hinges were built to push, while its handle was built to be pulled.

Affordances and signifiers

Design researchers use two plain words to separate what an object can do from what it tells you to do. The cognitive scientist Don Norman popularised them in design through his book The Design of Everyday Things, first published in 1988 as The Psychology of Everyday Things; its revised and expanded edition of 2013 added the idea of signifiers.

• An affordance is a relationship between an object and a person: what the object lets you do. A flat floor affords walking. A cup handle affords gripping with fingers. A heavy stone affords propping a door open, though not for a small child who cannot lift it.
• A signifier is the perceptible clue that tells you where and how to act. A flat brass plate at hand height signifies "push here". A vertical handle with space behind it for knuckles signifies "grip and pull".

What is the opposite of a good signifier? Not an ugly handle. It is a false signifier: a clue that invites the wrong action, like a pull bar mounted on the push side of a door just so both sides look symmetrical in a photograph.

Why does a home kitchen rarely need labels on its cupboards, while a public building often covers its doors in sticky notes? At home, you live with the mistake and memorise which cupboard sticks. In a hospital, a railway station or a court building, thousands of strangers arrive every day for the first time, often anxious or in a rush. Public design cannot rely on memory; the clue must be on the object itself.

Clear clue or misleading clue?

Five made-up everyday objects. Sort each one by whether its physical shape gives a clear signifier or a misleading one.

When a label is a confession

Do all signs mean bad design? No. A road sign naming a town 20 kilometres away gives information the road surface itself could never show. A label on a medicine bottle is essential.

I am not saying words have no place in design. I am saying that when a simple physical action like pushing a door, turning on a tap or flipping a switch needs a printed paragraph of instructions, the label is usually a bandage over a missing or false signifier. When you write your final paper at the end of this course, look for those bandages: wherever people keep making the same silly mistake, a bad signifier is usually hiding underneath.

Should public building rules ban pull handles on the push side of doors?

Some designers say building codes for schools, hospitals and offices should require flat plates on the push side of every swinging door. Others say architects should remain free to choose the hardware.

A hard case. A heritage library with pairs of carved wooden doors that swing both ways depending on the season. How should the handles be designed so visitors know which leaf opens which way?

Explore in World 101

Everyday objects are where industrial design and human perception meet. Open Product, Industrial and Interaction Design in World 101 and follow one link that surprises you.