Particle Vs Wave model of Cathode Rays (1 Viewer)

[snoopwogg]

(Revised) Particle Vs Wave model of Cathode Rays

Ok, for the fourth time, i finally realised wat i asked in the question.. so here it is...

In jaccaranda physics, they say that the fact the cathode rays did not APPEAR to be def;lected by electric fields (by hertz which turned out to be wrong) supported the particle theory. However, on hsc.csu.edu.au .. they say "Heinrich Hertz performed an experiment in 1883 that appeared to show that cathode rays were not deflected by electric fields. His experimental results were incorrect, however his result was used as evidence that cathode rays were electromagnetic waves, just like light which is not deflected by electric fields. "

So which is it, does that wrong observation support the wave or particle theory??

 

[za]

hmmmm......
good question

 

[snoopwogg]

.

 

[za]

i think it supported the wave theory at the time
but the reason that no deflection was seen was because this was due to the rays themselves. i.e. within the tube, the cathode rays ionized the gas. The ions were attracted to the plate with the opposite charge and the line-up of ions effectively neutralized the charge on the plate, allowing the cathode rays to pass unaffected. This was overcome by evacuating the chamber, resulting in a deflection taking place. This confirmed they were negatively charged particles

 

[snoopwogg]

thanks alot za, but im sorry to say that wasnt really what i was asking.
what i am asking though, is at the time that they didnt know if the cathode rays were particles or waves. what did that experiment by hertz support? the wave or particle theory??

 

[za]

maybe sum1 else can explain it in better terms

 

[kheir]

ur inconciderastely dum quest

on dis site we call ppl liku stupid u hav simply tried to mislead ppl sucha s i with ur jibberish for this i shall kik urarses

 

[za]

i dont think such rude comments are neccessary
he asked a decent question
i think u should apologise

 

[ashtor]

the debate about whether cathode rays werer electromagnetic waves or streams of charged particles remained unsloved until 1897 when JJ Thompson showed beyond doubt that the rays were streams of negatively vharged particles. The problem however was the inconistent ebhaviour of rays, and i think that is the pivotal point of your confusion snoopwog. To clarify this, the following observations are afew that fitted the wave model:
they travelled in straight lines
if an opaque object was placed in their path, a shadow of that object appeared
they could pass through thin metal foils without damaging them
The following observation fitted the particle model:
the rays left the cathode at right angles to the surafce
they were obvioudly deflected by magnetic fileds
tehey did not SEEM to be deflected by electric fields, but htis point was later disproven
and they travelled considerably slower than light

 

[snoopwogg]

yes thanks for your input as well mr ashtor, however, you too, like za, have misunderstood my question. i understand that it was later disproven.
however, the question is sir, that at that time, some hundred years ago, did Hertz's incorrect experiment support the wave model or particle model? the information seems to be contradicting themselves from the two sources (in jacaranda it says hertz's experiment supported the particle model and in hsc.csu.edu.au it said it supported the electromangetic wave model).

 

[snoopwogg]

May i also add, mr kheir, you are a total imbissile. It says above that that was your first post, and im afraid your are not off to an intelligent start my dear misguided friend. I hope you will wake up to yourself soon, because the HSC is not too far away, and this immaturity will get you nowhere.

 

[kikujiro]

i've got the new jacaranda and while i can't find anyhting about hertz and experiments concerning cathode rays, there's a small bit that says that Hertz supported the wavelength model, and so i guess his experiment would have supported the wavelength model (and that's why he believed in it)
don't know if that's any help though...

 

[+:: $i[Q]u3 ::+]

the observation the cat. rays did not deflect in the presence of an electric field supports the wave theory - (light does not deflect, but charged particles can).
i don't remember my jacaranda book saying that this supported the particle model. I could be wrong, but check ur book.

 

[ashtor]

It supports the wave model, as waves are not charged. Note also that the reason Hertz did not notice a deflection was because he did not evacuate his tube enough. The remaining gases were ionised by the cathode rays and neutralised the electrodes, hence removing the effect of the field. For this reason, and by noticing that electrons pass through thin sheets of gold, Hertz intorduced a new German view on the subject of cathode rays, proving, at the time that they were waves.
Joseph Thompson later improved a cathode ray tube and evaculated it to such an extent that the rays were deflected by the electric field (a stronger one this time). Also, Ernest Rutherford showed that cathode rays passed through thin gold sheets because atoms are mainly space, NOT because the cathode rays were waves. From these findings, we have come to accept cathode rays as a stream of negatively charged particles, and Hertz's findings have been disproven.

 

[hSc_n00plar]

In a nutshell ... Hertz was a proponent of the wave model of cathode rays believing that it was a phenomenon like light with a very short wavelength.

His experiment, which showed that cathode rays were undeflected by the charged plates supported the WAVE model (although it was found to be due to experimental error that this result was obtained)

 

[CrashOveride]

Originally posted by hSc_n00plar
(although it was found to be due to experimental error that this result was obtained)

Didn't we just say it was because his CRT was not evacuated?

Also, i cant find in my jacaranda book where it says that Hertz making the observation that cathode rays were undeflected by electric fields supported the particle theory ?? Maybe you made a slight interpretation error.

 

[Xayma]

Originally posted by CrashOveride
Didn't we just say it was because his CRT was not evacuated?

Also, i cant find in my jacaranda book where it says that Hertz making the observation that cathode rays were undeflected by electric fields supported the particle theory ?? Maybe you made a slight interpretation error.

It is because the tube wasnt evacuated enough, the ionised air effectively neutralised the field meaning it wasnt visibly deflected.

 

[xiao1985]

the observation didn't reject the wave particle theory imo... because it is accepted at the time that EMR waves cannot carry a charge... hence, if it IS actually deflected, then it is certain that it is not a wave... but since no deflection was observed, the wave theory is not rejected...

 

[za]

exactly