Compressible Fluids and Objects
The atmosphere's density depends upon altitude. As an airship rises in the atmosphere, its buoyancy decreases as the density of the surrounding air decreases. In contrast, as a submarine expels water from its buoyancy tanks, it rises because its volume is constant (the volume of water it displaces if it is fully submerged) while its mass is decreased.
Read more about this topic: Buoyancy
Famous quotes containing the word objects:
“Though collecting quotations could be considered as merely an ironic mimetism—victimless collecting, as it were ... in a world that is well on its way to becoming one vast quarry, the collector becomes someone engaged in a pious work of salvage. The course of modern history having already sapped the traditions and shattered the living wholes in which precious objects once found their place, the collector may now in good conscience go about excavating the choicer, more emblematic fragments.”
—Susan Sontag (b. 1933)