Modern Insights and Studies
Unlike macroscopic motion, molecular systems are constantly undergoing significant dynamic motions subject to the laws of Brownian mechanics (or Brownian motion), and as such, harnessing molecular motion is a far more difficult process. At the macroscopic level, many machines operate in the gas phase, and often, air resistance is neglected, as it is insignificant, but analogously for a molecular system in a Brownian environment, molecular motion is similar "to walking in a hurricane, or swimming in molasses." The phenomenon of Brownian motion (observed by Robert Brown (botanist), 1827) was later explained by Albert Einstein in 1905. Einstein found that Brownian motion is a consequence of scale and not the nature of the surroundings. As long as thermal energy is applied to a molecule, it will undergo Brownian motion with the kinetic energy appropriate to that temperature. Therefore, like Feynman's strategy, when designing a molecular machine, it seems sensible to utilize Brownian motion rather than attempt to fight against it.
Like macroscopic machines, molecular machines typically have movable parts. However, while everyday macroscopic machines may provide inspiration for molecular machines, it is misleading to draw analogies between their design strategy; the dynamics of large and small length scales are simply too different. Harnessing Brownian motion and making molecular level machines is regulated by the second law of thermodynamics, with its often counter-intuitive consequences, and as such, we need another inspiration.
Although it is a challenging process to harness Brownian motion, nature has provided us with several blueprints for molecular motion performing useful work. Nature has created many useful structures for compartmentalizing molecular systems, hence creating distinct non-equilibrium distributions; the cell membrane is an excellent example. Lipophilic barriers make use of a number of different mechanisms to power motion from one compartment to another.
Read more about this topic: Molecular Machine
Famous quotes containing the words modern, insights and/or studies:
“The experience of the gangster as an experience of art is universal to Americans. There is almost nothing we understand better or react to more readily or with quicker intelligence.... In ways that we do not easily or willingly define, the gangster speaks for us, expressing that part of the American psyche which rejects the qualities and the demands of modern life, which rejects “Americanism” itself.”
—Robert Warshow (1917–1955)
“The children [on TV] are too well behaved and are reasonable beyond their years. All the children pop in with exceptional insights. On many of the shows the children’s insights are apt to be unexpectedly philosophical. The lesson seems to be, “Listen to little children carefully and you will learn great truths.””
—G. Weinberg. originally quoted in “What Is Television’s World of the Single Parent Doing to Your Family?” TV Guide (August 1970)
“Possibly the Creator did not make the world chiefly for the purpose of providing studies for gifted novelists; but if he had done so, we can scarcely imagine that He could have offered anything much better in the way of material ...”
—Elizabeth Stuart Phelps (1844–1911)