Today in Physics: Augustin-Jean Fresnel 1788, inventor of the Fresnel lens

TODAY in PHYSICS!

The birth of Augustin-Jean Fresnel (pronounced freh-NEL) in 1788, who invented the Fresnel lens used in many physical optics applications.

How does it work? Light is refracted, or bent, when it travels from one medium to another. For example, according to Snell's Law, light traveling from glass to air bends outward. Fresnel used this concept to create a lens that could concentrate light without using a lot of material.

How did he do it? By making a series of steps in the glass lens, the light is refracted again and again until it focuses on the target. So simple but powerful, and economical!

The lens was first implemented in lighthouses (like the one above). Before Fresnel's invention, lighthouses were notorious for being too dim to see. During cloudy or stormy weather, ships could either risk hitting sharp rocks along the shore or stay out at sea with scarce food, water and supplies. By intensifying the signal brightness, the Fresnel lens improved communication between lighthouse operators and ship captains and allowed operators to warn captains of potential danger ahead.

Common uses for the Fresnel lens include your car lights and laser pointers. The lenses are getting attention today in solar power applications, where light focusing can improve efficiency.

Today in Physics: Manfred Eigen, 1967 Nobel Laureate in Chemistry

TODAY in PHYSICS!!

Born on this day in history: Manfred Eigen, biophysicist and awardee of the 1967 Nobel Prize in Chemistry.

Eigen, along with Ronald George Wreyford Norrish and George Porter, were awarded the prize for their work on fast chemical reactions.  Eigen and his colleagues studied reactions that took from 1 second to 1 nanosecond -- the time it takes light to travel about 1 foot (source: "Manfred Eigen - biographical." nobelprize.org, accessed May 9, 2013). To do this, they quickly disturbed the chemical system from equilibrium and measured the time it took to relax back. Unlike a classical or "slow" reaction, a fast chemical reaction speeds up with added product at a very nonlinear rate. Recently, reactions have been observed as fast as a femtosecond or 10^-15 seconds!

Eigen's work helped bridge the gap between classical reaction kinetics and spectroscopy, the molecular study of electron interactions. The work had many biological implications too, including a better understanding of metabolic processes and the development of new medical active ingredients. In order to improve healthcare with his scientific discoveries, Eigen co-founded the drug discovery company Evotec (source: "Manfred Eigen: 1967 - Chemistry." research-in-germany.com, accessed May 9, 2013).

The many awards bestowed upon Manfred Eigen include Honorary Doctorate degrees in Science from Harvard University, Washington University and the University of Chicago, the 1963 Kirkwood Medal, 1965 Harrison Howe Award and the 1967 Linus Pauling Medal from the American Chemical Society, and 7 honorary professorships or memberships of prestigious societies as well as a handful of awards from his native country, Germany.

Today, Eigen is 89 years old and still scientifically active. Besides his yearly travels to Boston to discuss leading biochemical questions, he is a keen amateur musician and enjoys mountaineering during the holidays.