jj thomson cathode ray tube experiment demonstrated that

Once he had this apparatus further experiments with electric and magnetic fields could reveal a great deal more about the particles. This enabled Thompson to refute the claim by Hertz that electric fields didn't cause deflection (maybe Hertz's glassblower wasn't as good).

The critical experiments done by Thompson relied on having an excellent glassblower who was able to construct an apparatus where electrodes inside the discharge tube which could be charged with an electric field (while retaining a very high vacuum).

Hertz, though, claimed electric fields would not deflect them (he was wrong). Later, scientists such as Crookes observed that the rays could be deflected by magnetic fields (though he thought they were just negatively charged gas particles). Initially the rays were seen to travel in straight lines. So the idea that some sort of ray was emitted by the cathode in the tube was developed. They were first observed as experiments in gas discharge tubes started to exploit better and better vacuums (the early experiments observed the varying forms of discharge in low pressure gases cathode rays only become significant when there is very little gas left in the tubes).Īt very high vacuums, people observed that the glass at the end of the tubes would glow even though the contents of the tubes did not (as there were too few gas particles left to cause a discharge). Thompson was able to measure the ratio of their mass to their speedĬathode 'rays' had been known for some time before Thomson.

Jj thomson cathode ray tube experiment demonstrated that