- #1
HJ Farnsworth
- 128
- 1
Greetings,
I have been having some fun in the last couple of days by looking at the details of historically significant experiments. One such is Thomson's discovery of the electron, in which he concluded that cathode rays were, in fact, composed of negatively charged, discrete particles. But as far as I can tell, his experiment (refresher - he put a cathode inside a glass tube under vacuum, the glass emits light where it is struck by the resulting cathode ray. Thomson used a magnetic field to divert the ray, indicating that the ray itself was charged) does not show that the ray is composed of discrete, negatively charged particles - it could just as easily be a continuous beam of negative charge.
How did he conclude that the beam was discrete, rather than continuous?
I want to make clear that I am not questioning the existence of electrons as particles. I know of plenty of evidence for that. This is primarily a historical question - how did Thomson, who did his experiment in the 1800s, figure out that a cathode ray was composed of particles?
Thanks for any help you can give.
-HJ Farnsworth
I have been having some fun in the last couple of days by looking at the details of historically significant experiments. One such is Thomson's discovery of the electron, in which he concluded that cathode rays were, in fact, composed of negatively charged, discrete particles. But as far as I can tell, his experiment (refresher - he put a cathode inside a glass tube under vacuum, the glass emits light where it is struck by the resulting cathode ray. Thomson used a magnetic field to divert the ray, indicating that the ray itself was charged) does not show that the ray is composed of discrete, negatively charged particles - it could just as easily be a continuous beam of negative charge.
How did he conclude that the beam was discrete, rather than continuous?
I want to make clear that I am not questioning the existence of electrons as particles. I know of plenty of evidence for that. This is primarily a historical question - how did Thomson, who did his experiment in the 1800s, figure out that a cathode ray was composed of particles?
Thanks for any help you can give.
-HJ Farnsworth