Crookes Tube

A Crookes tube is an early experimental electrical discharge tube, 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, it consists of a partially evacuated glass container of various shapes, with two metal electrodes, one at either end. When a high voltage is applied between the electrodes, cathode rays (electrons) travel in straight lines from the cathode to the anode. It was used by Crookes, Johann Hittorf, Juliusz 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.

Read more about Crookes Tube:  How A Crookes Tube Works, History, The Discovery of X-rays, Experiments With Crookes Tubes

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