Search results
Results from the WOW.Com Content Network
Zinc is an inexpensive and effective part of treatment of diarrhea among children in the developing world. Zinc becomes depleted in the body during diarrhea and replenishing zinc with a 10- to 14-day course of treatment can reduce the duration and severity of diarrheal episodes and may also prevent future episodes for as long as three months. [174]
The first black person on record to have successfully performed pericardium (the sac surrounding the heart) surgery to repair a wound. [191] Williams, Marguerite Thomas: 1895–1991 Geologist: First black person to receive a Ph.D. in Geology Williams, Scott W. 1943– Mathematician [192] Williams, Walter E. 1936–2020 Economist, social scientist
Perey discovered it as a decay product of 227 Ac. [177] Francium was the last element to be discovered in nature, rather than synthesized in the lab, although four of the "synthetic" elements that were discovered later (plutonium, neptunium, astatine, and promethium) were eventually found in trace amounts in nature as well. [178]
Joseph Black (16 April 1728 – 6 December 1799) was a Scottish physicist and chemist, known for his discoveries of magnesium, latent heat, specific heat, and carbon dioxide. He was Professor of Anatomy and Chemistry at the University of Glasgow for 10 years from 1756, and then Professor of Medicine and Chemistry at the University of Edinburgh ...
The other metals discovered before the Scientific Revolution largely fit the pattern, except for high-melting platinum: Bismuth melts at 272 °C (521 °F) [21] Zinc melts at 420 °C (787 °F), [21] but importantly boils at 907 °C (1665 °F), a temperature below the melting point of silver. Consequently, at the temperatures needed to reduce ...
The Silver Hill Mine (originally named King's Mine and Washington Mine prior to 1854) was the first silver mine in the United States, later used primarily as a source of lead and zinc. Discovered during the Carolina gold rush at a Davidson County, North Carolina location later named Silver Hill, operations began at the site in 1839 under the ...
Sphalerite is an important ore of zinc; around 95% of all primary zinc is extracted from sphalerite ore. [42] However, due to its variable trace element content, sphalerite is also an important source of several other metals such as cadmium, [ 43 ] gallium, [ 44 ] germanium, [ 45 ] and indium [ 46 ] which replace zinc.
The world's first ice-calorimeter, used in the winter of 1782–83, by Antoine Lavoisier and Pierre-Simon Laplace, to determine the heat involved in various chemical changes; calculations which were based on Joseph Black's prior discovery of latent heat. These experiments mark the foundation of thermochemistry.