Showing posts with label physicist. Show all posts
Showing posts with label physicist. Show all posts

Tuesday, January 5, 2010

Fahrenheit


(F) a temperature scale, devised by the German physicist Gabriel Fahrenheit (1686-1736), that set the freezing point of water at 32º and the boiling point at 212º. Fahrenheit temperatures can be converted to CELSIUS by the equation F = 1.8C + 32.

Taken from Dictionary of Science

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Fahrenheit is the temperature scale proposed in 1724 by, and named after, the physicist Daniel Gabriel Fahrenheit (1686–1736). Today, the temperature scale has been replaced by the Celsius scale in most countries. It is still in use for non-scientific purposes in the United States and a few other nations, such as Belize.


Taken from Wikipedia

Tuesday, December 29, 2009

Dalton's atomic theory



a milestone in the development of chemistry devised by the English chemist and physicist John Dalton (1766-1844). He put forward the theory that all matter is made up of particles (atoms), which are identical throughout one element or substance, and that chemical reaction occurs through the attraction between atoms.

Taken from Dictionary of Science

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It was in the early 1800s that John Dalton, an observer of weather and discoverer of color blindness among other things, came up with his atomic theory. Let's set the stage for Dalton's work. Less than twenty years earlier, in the 1780's, Lavoisier ushered in a new chemical era by making careful quantitative measurements which allowed the compositions of compounds to be determined with accuracy. By 1799 enough data had been accumulated for Proust to establish the Law of Constant Composition ( also called the Law of Definite Proportions). In 1803 Dalton noted that oxygen and carbon combined to make two compounds. Of course, each had its own particular weight ratio of oxygen to carbon (1.33:1 and 2.66:1), but also, for the same amount of carbon, one had exactly twice as much oxygen as the other. This led him to propose the Law of Simple Multiple Proportions, which was later verified by the Swedish chemist Berzelius. In an attempt to explain how and why elements would combine with one another in fixed ratios and sometimes also in multiples of those ratios, Dalton formulated his atomic theory.

Taken from Clackamas Community College Website