Appearance in Nature
A fish's swim bladder manipulates neutral buoyancy by controlling the amount of water and air in the swim bladder, allowing it to swim at different depths. This is achieved by having an average density that is lower than the surrounding water, with the density of the fish being counter-acted by the density of the air in the bladder.
On an interesting note, we all deal intimately with the phenomenon of neutral buoyancy every day—with our brains, which exhibit neutral buoyancy as a result of their suspension in cerebrospinal fluid. The actual mass of the human brain is about 1400 grams; however the net weight of the brain suspended in the CSF is equivalent to a mass of 25 grams. The brain therefore exists in neutral buoyancy, which allows the brain to maintain its density without being impaired by its own weight, which would cut off blood supply and kill neurons in the lower sections.
Read more about this topic: Neutral Buoyancy
Famous quotes containing the words appearance and/or nature:
“Now the appearance of the glory of the LORD was like a devouring fire on the top of the mountain in the sight of the people of Israel.”
—Bible: Hebrew, Exodus 24:17.
“Our bread need not ever be sour or hard to digest. What Nature is to the mind she is also to the body. As she feeds my imagination, she will feed my body; for what she says she means, and is ready to do. She is not simply beautiful to the poet’s eye. Not only the rainbow and sunset are beautiful, but to be fed and clothed, sheltered and warmed aright, are equally beautiful and inspiring. There is not necessarily any gross and ugly fact which may not be eradicated from the life of man.”
—Henry David Thoreau (1817–1862)