Temperature-sensing paints work similarly they use luminescent molecules that light up according to how much they are vibrating, glowing less (and shaking more) when they are hotter and glowing more (and shaking less) when they are cooler.

ECONOMIST: Pressure paints

In their latest experiment, Dr Sullivan and his colleagues painted the blades of a rotor with both temperature-and pressure-sensing paints, shone laser light on to them, and mapped out the temperatures and pressures as the blades whirred around as fast as 14, 000 rotations per minute.

ECONOMIST: Pressure paints