Every weighing in the laboratory leans on gravity, the gravitational force acting on any object within the earth’s field, the attraction between massive bodies. The force of gravity on a body determines its weight, and the centre of gravity marks the point where total weight acts, a concept packaging engineers use to keep stacks stable. Food science meets gravity in specific gravity, the figure comparing a substance’s weight with that of an identical volume of water, used to check syrups, brines and wort strength.