These get their name because they come from the (conventionally) negative of the two terminals which lead the current in and out, which Whewell, then Master of Trinity College, Cambridge, called ‘cathode’ after Faraday had asked him for suggestions.* They appear as straight lines diverging from points on the cathode and show up as phosphorescence when they reach the glass walls. Soon after the stage when the density allows the discharge to pass most easily the brilliantly coloured display of lights in the tube begins to show a new feature, called the cathode rays. Some gas is needed, in fact, but not too much. When for example the air in a glass tube is reduced to a density about 1/ 3000 of the normal an electric current can be passed through it with far less than the voltage which would be needed if most of the air had not been pumped out, though if the density is reduced by still another factor of io or so it again becomes harder to pass a current. These are one of the many strange phenomena which occur when electricity is made to pass through highly rarificd gases. The experiment in question had nothing to do with these waves, it concerned the nature of cathode rays. One of his most outstanding legacies consisted in the discovery of what is now known as protons, along with channel rays, also known as anodic or positive rays.
Beams of electrons are directed from the cathode to the anode.
#WHEN WAS THE CATHODE RAY EXPERIMENT DONE FREE#
Hertz, the first man to prove experimentally that electromagnetic waves exist and can be propagated in free space. This discovery was carried out through experimentation with cathode ray tubes, in 1886. In making sense of a complicated set of scientific facts, or claimed facts, it often happens that one turns out to be wrong, but it is rare for the villain to be an experiment by as great a physicist as H.
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