subject
Engineering
How designers work under constraints — strength, cost, failure, time — and the reasoning that turns a physical principle into something that holds up in the world.
12 lessons in engineering
Centralized and Distributed Systems: Two Ways to Build at Scale
Imagine a busy library with a single front desk. Every borrower checks books in and out at one counter, where one librarian holds the only ledger. The system is easy to understand: there is exactly on…
4 min · comparison
How a Heat Engine Turns Temperature Differences into Work
Hold a kettle on a hot stove and lift its whistling lid: the steam that hisses out carries energy, and if you channeled that steam against a paddle, the paddle would spin.
3 min · foundation
How a Microwave Heats Food
Open the door of a microwave and there is nothing inside but a glass tray and a metal box.
3 min · foundation
How a Transistor Switches
Press a key on a keyboard and somewhere inside the machine, a few billion tiny switches flip.
4 min · deepening
How GPS Knows Where You Are
Open the map app on your phone, and a blue dot appears within a few seconds, usually within ten or fifteen feet of where you actually are.
3 min · deepening
What Feedback Control Actually Does
A home thermostat is the most domestic example of one of the most consequential ideas in engineering.
4 min · foundation
Why Bridges Don't Fall: Forces in a Truss
Stand under a railway bridge as a freight train passes overhead and you will feel, in your chest, the weight of several hundred tons being held up by what looks like nothing — a lattice of steel bars,…
4 min · foundation
Why Concrete Cracks: Tension, Compression, and Reinforcement
Walk under almost any highway overpass and look up. You will see hairline cracks running along the underside of the deck, often in surprisingly regular patterns. The bridge is not failing. It is doing…
4 min · deepening
Why Engineering Is the Discipline of Tradeoffs
A bridge can be stronger, or it can be cheaper. It can be lighter, or it can last longer in salt air. It can be fast to build, or it can be elegant enough to become a city's postcard. What it cannot d…
4 min · synthesis
Why Planes Fly
Stick your hand out of a car window on the highway. Hold it flat, palm down. Now tilt the front edge of your hand up just a little. You feel your hand get shoved upward, hard. You did not change the e…
3 min · foundation
Why Skyscrapers Don't Topple in Wind
Stand at the base of an 80-story building on a gusty day and look up.
3 min · foundation
Wind and Solar: Two Ways to Make Power Without Fuel
Stand next to a wind turbine on a breezy hillside and you can feel the blades chopping the air with a low whoosh.
3 min · comparison