What is a scale on a map?

A map is almost always smaller than the place it describes. If a map of the US were drawn in its actual size, it would be 3,000 miles wide, and very difficult to fold. ... The scale of the map is the ratio of a distance on the map to the same distance on the real thing. ... If the map scale is 1 : 50000, then 1 foot on the map shows things that are actually spread over 50000 feet in the real city or field.

It is less dense than the surrounding water