Millstone

part · 9000 BC · Stone Age

A stone disc for grinding grain.

Principles and materials it uses

Stone — is made of. Millstones were hewn from hard stone.
Friction — uses. Grain is ground by friction between the stones.

Where it is used

Quern — is part of. Grain is ground between millstones.
Watermill — is part of. The wheel turns the millstones.
Windmill — is part of. A windmill turns the millstones.
Gristmill — is part of. Grain is ground by millstones.

Take Millstone apart