Radiometric effect (1 Viewer)

[Run hard@thehsc]

Since it was found that the paddle wheel moved by the radiometric effect, how can we use the 'Paddle wheel' experiment to deduce the nature of electrons?

 

[Life'sHard]

You can’t. The whole basis of the paddle wheel was to prove whether cathode rays carried momentum. But the wheels moved due to the radiometric effect which basically negates any observations which could be related to the nature of an electron due to the fact that the whole experiment relies on the rotation of the wheel.

 

[Run hard@thehsc]

fair - so if in the instance a q asks about what this experiment informs us about.... what would be best to discuss?

 

[Bob99]

Since it was found that the paddle wheel moved by the radiometric effect, how can we use the 'Paddle wheel' experiment to deduce the nature of electrons?

wtf is the radiometric effect. Didn't the paddle move cuz cathode rays (electrons) possessed momentum, hence transfer of energy --> paddle wheel moved?

 

[vivekjain0908]

wtf is the radiometric effect. Didn't the paddle move cuz cathode rays (electrons) possessed momentum, hence transfer of energy --> paddle wheel moved?

that was crookes innitial hypothesis (dk if thats the right word) but later it was found that they moved due to the radiometric effect, which is essentially one side of the paddle got hot relative to the other due to the constant barrage of cathode rays and hence it rotated, fyi this is a very very basic explanation in laymans terms

 

[Life'sHard]

fair - so if in the instance a q asks about what this experiment informs us about.... what would be best to discuss?

Talk about initial assumptions and what the scientists thought they were discovering. Then talk about the flaws in the experiment and what actually happened.

 

[vivekjain0908]

Talk about initial assumptions and what the scientists thought they were discovering. Then talk about the flaws in the experiment and what actually happened.

could we then conclude with like how this is not a valid experiment for determing the propertieas of electrons

 

[Run hard@thehsc]

could we then conclude with like how this is not a valid experiment for determing the propertieas of electrons

sure if you want to lol

 

[wizzkids]

You are right. All you can conclude is that cathode rays transmit energy, but whether they are particles or waves is impossible to say. Crookes incorrectly attributed the motion of the paddle wheel to momentum transfer from his cathode rays. About 20 years later, J J Thompson (using his new estimate for the mass of the electron) was able to show that the momentum of cathode rays was about two orders of magnitude too small to account for the acceleration of the paddle wheel. Thompson attributed the motion to the radiometric heating of the front and back surface of the paddle, and the residual gas molecules in the Crookes tube.

 

[Vall]

TLDR: don’t talk about the paddle wheel as evidence for the electron as a wave/particle unless the question specifically says to