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Stern and Gerlach Experiment

Posted: Fri Oct 07, 2016 6:28 pm
by Aleena_Sorf_2A
How does the Stern and Gerlach Experiment demonstrate electron spins?

Re: Stern and Gerlach Experiment  [ENDORSED]

Posted: Fri Oct 07, 2016 6:49 pm
by Eunnie_Lee_3H
As seen in the course reader page 62, the set up was to have an atom beam of silver atoms going through a magnetic field, which would hit a collection plate on the other side.

What happened was that the atoms (which were in their ground state with their 1 unpaired electron) were accumulating on two different points, one up and one down, of the collection plate, when they were expecting the atoms to be evenly distributed between the two points. There's a 50/50 chance of the electron being in an "up" or "down" spin (+1/2 or -1/2 ms), so the "up" and "down" spins of the electrons was what made the atoms accumulate in those two distinct points.

Ok so I found this video on Wikipedia so it may not be 100% reliable, but I think this demonstrates what they expected to happen vs what actually happened and why pretty well: ... riment.ogv

Re: Stern and Gerlach Experiment

Posted: Fri Oct 07, 2016 7:48 pm
by Drake_Everlove_1K
So, I'm still not sure I know exactly what quantum spin entails. Is the electron literally spinning on an axis? What is is spinning "up" and "down relative to? Does it affect its motion around the atom or other electrons, and why exactly is it significant if not? Why can electron spin only have two values? Since they can only be spinning by 1/2, does that indicate there are literally only two directions in which electyrons can spin and that all electrons in the universe are spinning "up" and "down" against a certain relative point, or can spin happen in any direction in 3D space?