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:
“Though an unpleasant sort of person, and even a queer threatener withal, yet, if one meets him, one must get along with him as one can; for his ignorance is extreme. And what under heaven indeed should such a phantasm as Death know, for all that the Appearance tacitly claims to be somebody that knows much?”
—Herman Melville (1819–1891)
“A man with your experience in affairs must have seen cause to appreciate the futility of opposition to the moral sentiment. However feeble the sufferer and however great the oppressor, it is in the nature of things that the blow should recoil upon the aggressor. For God is in the sentiment, and it cannot be withstood.”
—Ralph Waldo Emerson (1803–1882)