Crookes tube
A Crookes tube is an early experimental electrical discharge tube, with partial vacuum, invented by English physicist William Crookes and others around 1869-1875, in which cathode rays, streams of electrons, were discovered.
Developed from the earlier Geissler tube, the Crookes tube consists of a partially evacuated glass container of various shapes, with two metal electrodes, the cathode and the anode, one at either end. When a high voltage is applied between the electrodes, cathode rays (electrons) are projected in straight lines from the cathode. It was used by Crookes, Johann Hittorf, Julius Plücker, Eugen Goldstein, Heinrich Hertz, Philipp Lenard and others to discover the properties of cathode rays, culminating in J.J. Thomson's 1897 identification of cathode rays as negatively charged particles, which were later named electrons. Crookes tubes are now used only for demonstrating cathode rays.
Wilhelm Röntgen discovered X-rays using the Crookes tube in 1895. The term is also used for the first generation, cold cathode X-ray tubes, which evolved from the experimental Crookes tubes and were used until about 1920.
Crookes
Coordinates: 53°23′02″N 1°30′29″W / 53.384°N 1.508°W
Crookes is a suburb of the City of Sheffield, England, about 1.5 miles (2.4 km) west of the city centre. It borders Broomhill to the south, Walkley and Crookesmoor to the east and open countryside around the River Rivelin to the north. The suburb is said to derive its name from the Old Norse "Krkor" which means a nook or corner of land.
The Bole Hills ( 53°23′26″N 1°30′38″W / 53.390597°N 1.510491°W ) at Crookes, overlooking the Rivelin Valley, were the site of open air smelting, and Bronze Age (about 1500 BC) funerary remains, similar to those of contemporary tribes sometimes called the Urn people, were found near this site in 1887. Sidney Addy reports the find in his 1888 book on the Sheffield area citing:
"On Easter Sunday [1887] Mr. Herbert T. Watkinson, of Summer Street, was walking in Cocked Hat Lane, (later to become Tinker Lane) near the Bole Hills, at Crookes, when he noticed in the side of an excavation that had been made for the foundations of some new houses what looked like a drain pipe. Closer examination revealed two rude earthenware urns, one inverted within the other, and the two containing a quantity of calcined bones, some broken fragments of a bronze spear-head or dagger, and a smaller urn pierced on one side with two round holes. The outer urn fell to pieces, but the one inverted within it was recovered whole. It is of a type very common in British burial mounds, and stands 9½ inches high, and measures across the mouth 7¼ inches, while the largest circumference is 26 inches. It is ornamented with the familiar straight and diagonal lines, and rows of dots. The urns lay six or eight inches below the surface, and were surrounded with charcoal. We are glad to hear that this curious relic of our ancient British ancestors will be exhibited in the Weston Park Museum."
Crookes (surname)
Crookes is a surname. Notable people with the surname include:
Crookes (crater)
Crookes is a lunar impact crater that lies on the Moon's far side as seen from the Earth. It lies just to the southwest of the giant crater Korolev. To the southwest of Crookes is McKellar.
The rim of this crater has a relatively high albedo compared to most such formations on the Moon, and it lies at the center of a ray system. This ejecta forms a nearly continuous blanket out to at least one crater diameter before forming extended rays and a multitude of wispy markings across the surface. The ray system continues for several hundred kilometers, including extending across a substantial portion of the Korolev basin. Due to these prominent rays, Crookes is mapped as part of the Copernican System.
As would be expected for a relatively young crater, Crookes has a sharp-edged rim that has not been significantly eroded. The inner walls are relatively wide, and have slumped inward along the edges. Offset slightly to the east of the midpoint of the crater is a small central peak on the interior floor.
