December 25 is Ernst Ruska’s birthday. Ruska was a German physicist who developed the first working electron microscope in 1933.
The electron microscope works much like an optical microscope except for one main difference. The optical microscope uses glass to bend light to focus an image to increase magnification where an electron microscope uses magnetic coils to bend streams of electrons to focus an image. The resolving power of microscopes is limited by the wavelength of the light used to illuminate the sample. Visible light microscopes are limited to resolving powers of the order of 1000x. The wavelength of electrons allows for resolving powers on the order of 1,000,000x. This device opened a new era of study of the microscopic world and earned Ruska half the 1986 Nobel Prize in Physics and a place in science history.
Notable Science History Events for December 25
1961 – Otto Loewi died.
Loewi was a German pharmacologist who shares the 1936 Nobel Prize in Medicine with Henry Dale for the discovery of acetylcholine. Acetylcholine is a chemical that functions as a neurotranmitter to activate and deactivate muscles. It is also the primary transmitter in the parasympathetic part of the autonomic nervous system and required for memory and cognition function.
He also investigated diabetes and the actions of the drugs digitalis and epinephrine.
1906 – Ernst Ruska was born.
1904 – Gerhard Herzberg was born.
Herzberg was a German physical chemist who earned the 1971 Nobel Prize in Chemistry for spectroscopic determination of the geometry and structure of free radicals. He was also a pioneer in the use of spectroscopy in astronomy. He was among the first to show molecules exist in space where it was previously believed ultraviolet radiation from the Sun would break any complex molecules apart.
1876 – Adolf Otto Reinhold Windaus was born.
Windaus was a German chemist who was awarded the 1928 Nobel Prize in Chemistry for his research into cholesterol and other sterols and their relation to vitamins. He discovered a chemical precursor that, when exposed to sunlight, creates vitamin D. This shows how sunlight can prevent rickets, a vitamin D deficiency.
1761 – William Gregor was born.
Gregor was a British mineralogist and clergyman who discovered the element titanium. He named his discovery manaccanite after the Manaccan valley where he found it. A few years later, Martin Klaproth thought he discovered a new element in the mineral rutile and named it titanium. Gregor was ultimately given credit for the discovery, but the name titanium remained.
1642 – Issac Newton was born.
Newton was an English scientist who is best known for his classical mechanics laws of motion, gravitation laws and the development of the mathematics of calculus. He was the first to demonstrate light could be separated into different colors with a prism and theorized an object’s color was caused by the color of the light reflecting off the object. He also built the first operational reflecting telescope. Newton is considered one of the most influential scientists in history.