3D-Printed ‘Metamaterial’ Shrinks When Heated, Defying Conventional Physics

If you leave a pot of milk on the stove with the heat turned up, it boils over and you have to clean up the mess. Why it happens is because milk, like most other things and almost all solids, expands under the effect of heat, the same quantity occupying more space than it did previously.

While there are some materials in nature that buck the usual thermodynamics and behave differently under very specific circumstances, they are rare. But a team of engineers has now constructed, using 3D-printing, a new “metamaterial” that shrinks when heated.