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Cloud Chamber
A cloud chamber, also known as a Wilson chamber, is a particle detector used for visualizing the passage of ionizing radiation. A cloud chamber consists of a sealed environment containing a supersaturated vapor of water or alcohol. An energetic charged particle (for example, an alpha or beta particle) interacts with the gaseous mixture by knocking electrons off gas molecules via electrostatic forces during collisions, resulting in a trail of ionized gas particles. The resulting ions act as condensation centers around which a mist-like trail of small droplets form if the gas mixture is at the point of condensation. These droplets are visible as a "cloud" track that persists for several seconds while the droplets fall through the vapor. These tracks have characteristic shapes. For example, an alpha particle track is thick and straight, while a beta particle track is wispy and shows more evidence of deflections by collisions. Cloud chambers were invented in the early 1900s by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ionizing Radiation
Ionizing (ionising) radiation, including Radioactive decay, nuclear radiation, consists of subatomic particles or electromagnetic waves that have enough energy per individual photon or particle to ionization, ionize atoms or molecules by detaching electrons from them. Some particles can travel up to 99% of the speed of light, and the electromagnetic waves are on the high-energy portion of the electromagnetic spectrum. Gamma rays, X-rays, and the higher energy vacuum ultraviolet, ultraviolet part of the electromagnetic spectrum are ionizing radiation; whereas the lower energy ultraviolet, visible light, infrared, microwaves, and radio waves are non-ionizing radiation. Nearly all types of laser light are non-ionizing radiation. The boundary between ionizing and non-ionizing radiation in the ultraviolet area cannot be sharply defined, as different molecules and atoms ionize at Ionization energies of the elements (data page), different energies. The energy of ionizing radiation starts ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carl David Anderson
Carl David Anderson (September 3, 1905 – January 11, 1991) was an American particle physicist who shared the 1936 Nobel Prize in Physics with Victor Francis Hess for his discovery of the positron. Biography Anderson was born in New York City, the son of Swedish immigrants. He studied physics and engineering at Caltech ( B.S., 1927; Ph.D., 1930). Under the supervision of Robert A. Millikan, he began investigations into cosmic rays during the course of which he encountered unexpected particle tracks in his (modern versions now commonly referred to as an Anderson) cloud chamber photographs that he correctly interpreted as having been created by a particle with the same mass as the electron, but with opposite electrical charge. This discovery, announced in 1932 and later confirmed by others, validated Paul Dirac's theoretical prediction of the existence of the positron. Anderson first detected the particles in cosmic rays. He then produced more conclusive proof by shootin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ben Nevis
Ben Nevis ( ; , ) is the highest mountain in Scotland, the United Kingdom, and the British Isles. Ben Nevis stands at the western end of the Grampian Mountains in the Highland region of Lochaber, close to the town of Fort William. The mountain is a popular destination, attracting an estimated 150,000 visitors a year, around three-quarters of whom use the Mountain Track from Glen Nevis. The mountain has hosted a foot race since 1898. The cliffs of the north face are among the highest in Scotland, providing classic scrambles and rock climbs of all difficulties for climbers and mountaineers. They are also the principal locations in Scotland for ice climbing. The cliffs of the north face can be viewed from the Charles Inglis Clark Memorial Hut, a private alpine hut. The summit is above sea level and is the highest land in any direction for . The summit is a stony plateau (a felsenmeer). It features a number of monuments and the ruins of an observatory which was continu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brocken Spectre
A Brocken spectre (British English; American spelling: Brocken specter; ), also called Brocken bow, mountain spectre, or spectre of the Brocken is the magnified (and apparently enormous) shadow of an observer cast in mid air upon any type of cloud opposite a strong light source. The figure's head can be surrounded by a bright area called , or Halo (optical phenomenon), halo-like rings of rainbow-coloured light forming a glory (optical phenomenon), glory, which appear opposite the Sun's direction when uniformly sized water droplets in clouds refract and backscatter sunlight. The phenomenon can appear on any misty mountainside, cloud bank, or be seen from an aircraft, but the frequent fogs and low-altitude accessibility of the Brocken, the highest peak of the Harz Mountains in Germany, have created a local legend from which the phenomenon draws its name. The Brocken spectre was observed and described by Johann Silberschlag in 1780, and has often been recorded in literature about t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Physicist
A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate causes of Phenomenon, phenomena, and usually frame their understanding in mathematical terms. They work across a wide range of Physics#Research fields, research fields, spanning all length scales: from atom, sub-atomic and particle physics, through biological physics, to physical cosmology, cosmological length scales encompassing the universe as a whole. The field generally includes two types of physicists: Experimental physics, experimental physicists who specialize in the observation of natural phenomena and the development and analysis of experiments, and Theoretical physics, theoretical physicists who specialize in mathematical modeling of physical systems to rationalize, explain and predict natural phenomena. Physicists can apply their k ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scottish People
Scottish people or Scots (; ) are an ethnic group and nation native to Scotland. Historically, they emerged in the Scotland in the Early Middle Ages, early Middle Ages from an amalgamation of two Celtic peoples, the Picts and Gaels, who founded the Kingdom of Scotland (or ''Kingdom of Alba, Alba'') in the 9th century. In the following two centuries, Celtic-speaking Hen Ogledd, Cumbrians of Kingdom of Strathclyde, Strathclyde and Germanic-speaking Anglo-Saxons, Angles of Northumbria became part of Scotland. In the Scotland in the High Middle Ages, High Middle Ages, during the 12th-century Davidian Revolution, small numbers of Normans, Norman nobles migrated to the Lowlands. In the 13th century, the Norse-Gaels of the Kingdom of the Isles, Western Isles became part of Scotland, followed by the Norsemen, Norse of the Northern Isles in the 15th century. In modern usage, "Scottish people" or "Scots" refers to anyone whose linguistic, cultural, family ancestral or genetic origin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Manhattan Project
The Manhattan Project was a research and development program undertaken during World War II to produce the first nuclear weapons. It was led by the United States in collaboration with the United Kingdom and Canada. From 1942 to 1946, the project was directed by Major General Leslie Groves of the United States Army Corps of Engineers, U.S. Army Corps of Engineers. Nuclear physicist J. Robert Oppenheimer was the director of the Los Alamos Laboratory that designed the bombs. The Army program was designated the Manhattan District, as its first headquarters were in Manhattan; the name gradually superseded the official codename, Development of Substitute Materials, for the entire project. The project absorbed its earlier British counterpart, Tube Alloys, and subsumed the program from the American civilian Office of Scientific Research and Development. The Manhattan Project employed nearly 130,000 people at its peak and cost nearly US$2 billion (equivalent to about $ b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radiography
Radiography is an imaging technology, imaging technique using X-rays, gamma rays, or similar ionizing radiation and non-ionizing radiation to view the internal form of an object. Applications of radiography include medical ("diagnostic" radiography and "therapeutic radiography") and industrial radiography. Similar techniques are used in airport security, (where "body scanners" generally use backscatter X-ray). To create an image in conventional radiography, a beam of X-rays is produced by an X-ray generator and it is projected towards the object. A certain amount of the X-rays or other radiation are absorbed by the object, dependent on the object's density and structural composition. The X-rays that pass through the object are captured behind the object by a X-ray detector, detector (either photographic film or a digital detector). The generation of flat two-dimensional images by this technique is called Projection radiography, projectional radiography. In computed tomography (C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cosmic Rays
Cosmic rays or astroparticles are high-energy particles or clusters of particles (primarily represented by protons or atomic nuclei) that move through space at nearly the speed of light. They originate from the Sun, from outside of the Solar System in our own galaxy, and from distant galaxies. Upon impact with Atmosphere of Earth, Earth's atmosphere, cosmic rays produce air shower (physics), showers of secondary particles, some of which reach the Earth's surface, surface, although the bulk are Deflection (physics), deflected off into space by the Earth's magnetic field, magnetosphere or the heliosphere. Cosmic rays were discovered by Victor Francis Hess, Victor Hess in 1912 in balloon experiments, for which he was awarded the 1936 Nobel Prize in Physics. Direct measurement of cosmic rays, especially at lower energies, has been possible since the launch of the first satellites in the late 1950s. Particle detectors similar to those used in nuclear and high-energy physics are u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clifford Charles Butler
Sir Clifford Charles Butler FRS (20 May 1922 – 30 June 1999) was an English physicist, best known for the discovery of the hyperon and meson types of particles. In later life, Butler was involved in educational policy, serving as director of the Nuffield Foundation and vice-chancellor of Loughborough University. Life Butler was born in Reading on 20 May 1922, the son of Charles Hannington James Butler, a clerk and buyer to a local wholesale grocer, and his wife Olive Pembroke. He attended both Reading School and the University of Reading, becoming both a Bachelor of Science and a Doctor of Philosophy there. He was appointed assistant lecturer in physics at the University of Manchester in 1945, and lecturer in 1947. In the same year he married Kathleen Betty Collins. They had two daughters. He died in Glenfield Hospital, near Leicester on 30 June 1999. Work At Manchester, Butler worked with G. D. Rochester, studying cosmic rays using a cloud chamber. During this research, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
