What is heavier: a pound of feathers or a pound of stone?

A pound of feathers and a pound of stone both weigh the same because they are equal quantities of mass, each measuring one pound. The question plays on common assumptions and intuitive reasoning about materials. People may think of stones as being much heavier due to their density and size, but when weight is being measured, the distinction between types of materials does not change the fact that a pound is a pound regardless of whether it is feathers, stones, or any other substance.

The confusion often arises from visualizing the volume that each material occupies. While a pound of feathers will take up much more space due to their lower density, it does not affect the weight measurement. Both materials, when measured in pounds, are equivalent in weight.