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I understand that Plucker showed that cathode rays travelled in straight lines, but what was his conclusion? From what I understand, it didn't conclusively supported a wave or particle model, but I have heard conflicting things where some people say Plucker interpreted it as supporting a wave model.

Also another thing is why the sharp shadow is even produced? Since the cathode rays are just electrons, didn't Davisson and Germer show that electrons can diffract, so shouldn't it be slightly fuzzy?

Sorry if dumb question I'm not that good at physics...

physicsphil
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The name "cathode ray" gives a clue as to what early experimenter thought.

Something which emanated from the cathode (negative electrode) of a discharge tube with word ray meaning a beam. The Maltese cross experiment was one which showed that this "something" travelled in straight lines and formed a shadow of a cross akin to the shadow produced by a light source.

The shadow did not have a perfectly sharp edge as the source of cathode rays was not a point. Any diffraction effects due to the edge could not be observed as the wavelength of the electrons was very small, $\approx \rm pm$ and no electrons passed through the cross.

This sort of experiment was first done prior to 1900 which is many years before the notion of "matter waves".

Farcher
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