The governing fact is adhesion. Steel on steel produces very little grip, which is efficient on the level and useless on a slope - so the route must be flattened…
The height is the mechanism, not the storage. Here are sixteen.
1. The Height Is the Pressure
Water pressure at a tap comes from the vertical distance down from the…
A traffic light looks like the simplest control system in existence: three lamps, one at a time, in a fixed order. Almost everything about it is a compromise between constraints…
Mostly about air, not water. Here are fifteen.
1. The Bend Is Holding Water on Purpose
Every fixture has a trap, a dip in the pipe that retains water after…
Watch the top of an escalator for a few seconds and something slightly impossible happens. A flat plate slides out from under a comb, then rises into a step, then…
The lift is the piece of machinery most people use most often without ever seeing any of it. What is visible is a box and two doors. What makes it…