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Crook_Paddlewheel

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ID = 68542
       
 
   
Tube type:  Geissler Crookes Elster-Geitel Hittorf 
Identical to Crook_Paddlewheel

Filament
Description

Wikipedia

"Crookes tubes evolved from the earlier Geissler tubes, experimental tubes which are similar to modern neon tube lights. Geissler tubes had only a low vacuum, around 10−3 atm (100 Pa),[6] and the electrons in them could only travel a short distance before hitting a gas molecule. So the current of electrons moved in a slow diffusion process, constantly colliding with gas molecules, never gaining much energy. These tubes did not create beams of cathode rays, only a colorful glow discharge that filled the tube as the electrons struck the gas molecules and excited them, producing light."

For 1879: "Crookes put a tiny vaned turbine or paddlewheel in the path of the cathode rays, and found that it rotated when the rays hit it. The paddlewheel turned in a direction away from the cathode side of the tube, suggesting that the rays were coming from the cathode. Crookes concluded at the time that this showed that cathode rays had momentum, so the rays were likely matter particles. However later it was concluded that the paddle wheel turned not due to the momentum of the particles (or electrons) hitting the paddle wheel but due to the radiometric effect. When the rays hit the paddle surface they heated it, and the heat caused the gas next to it to expand, pushing the paddle. This was proven in 1903 by J. J. Thomson who calculated that the momentum of the electrons hitting the paddle wheel would only be sufficient to turn the wheel one revolution per minute. All this experiment really showed was that cathode rays were able to heat surfaces."

Charge

"Jean-Baptiste Perrin wanted to determine whether the cathode rays actually carried negative charge, or whether they just accompanied the charge carriers, as the Germans thought. In 1895 he constructed a tube with a 'catcher', a closed aluminum cylinder with a small hole in the end facing the cathode, to collect the cathode rays. The catcher was attached to an electroscope to measure its charge. The electroscope showed a negative charge, proving that cathode rays really carry negative electricity."

 

 

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