the story of quantum mechanics is just that ....... it's a story
it was fabricated by generations of scientists to explain observations
that we really may have no
way to actually understand
but there's cool things about the world of quantum mechanics
and one of them is that it relates very much to the electromagnetic spectrum
quantum mechanics is all about energy levels and
energy levels are all about the electromagnetic spectrum
and the electromagnetic spectrum is something that ..
sometimes at least,
we can actually literally see
so let's take a look at this
about the turn of the last century .. about 1900
molecular anatomic behavior was starting to be understood
Max Planck had come up with the idea that maybe energy can come in packages
instead of being continuous
Ernest Rutherford had conducted his famous gold foil experiment
and it was understood that the protons are in the middle and the electrons are on the outside
the protons and the electrons are attracted to each other
the world of physics at this time was dominated by the work of Sir Isaac Newton Newton
Newton is all about force equals mass times acceleration
the formula for centrifugal force is this one
so under Newtonian physics the electrons go around the protons
and are attracted by gravitation and separated by centrifugal force
so the force is between the positive and the negative charges
the mass is the mass of the electron
the velocity would be the linear velocity of the electron
and the radius would be the distance between the electron and the proton
so the physicists around the world, look at this
and realize that this is not going to work....
Newtonian physics is not going to work for atomic structure
Niels Bohr in 1913 broke the ice with this
Niels Bohr says "this is not gonna work guys … we're gonna have to come up with something different
… we're gonna have to start making stuff up"
"I want to start the ball rolling with this"
electrons are in stable energy levels
we know that to be true
there are other stable energy levels and when an electron
moves from one stable energy to another, a piece of energy is either absorbed
or given off and that piece of energy looks like one of Max Planck's photons
this is the simplest graph you could ever imagine
there's no x-axis whatsoever .. the y-axis represents energy but notice there's no numbers on it
let's put an electron in this in this energy level
so we have an electron in the stable energy level
Niels Bohr used hydrogen so let's just use hydrogen
we take the hydrogen and we excite the electron in some way like
perhaps with a spark … with high temperature ... something like that ....
and this electron will move to a higher energy level
and that change is associated with a photon
that's a discrete amount associated with a discrete amount of energy
this is right out of the work of Max Planck
so and ... and ... if the
if the hydrogen atom is excited even more
the the electron might jump up ....... to this higher energy level
so these are two different jumps and there
are two different photons associated with them ...... they're very distinct
this is a distinct photon and this is a distinct photon
which moves the electron up to this level
and then up to this level
and that's pretty much the whole story
I want to look at one more graphic
so this is another simple graph
this graph represents the electromagnetic spectrum
so this is a part of the very very large
...you know..... radio waves and infrared and ultraviolet and gamma rays and
microwaves and x-rays …. fit on the electromagnetic spectrum
we have an electron and we excite it into an into a different energy level
it absorbs a specific wavelength
it absorbs a specific proton (photon)
okay we excited further it jumps up to yet another higher level
and gives us another photon at a higher energy
and then there's a statistical certainty
that an electron will jump ..... make the first jump
and then turn around and make the second jump
so it's going to jump to here
and jump to here
so this this piece is going to give us a little tiny peak
it's not going to be very big
be like maybe about right here and it's gonna be real small
there is a statistical certainty that an electron will jump and then jump again but
there's also a statistical unlikelihood so the peaks not going to be very big
and that's that's pretty much all there is to it ….
the frequency is going up in this direction
which means that the bigger the jump is the higher the frequency
niels bohr by no means ended this story niels bohr just started things rolling
the mathematicians especially Schrodinger and Niels Bohr himself
turned around and started adding complex mathematics to this
but as data was collected, the model got more and more complicated
but this is essentially the nuts and bolts of it
the cool thing is that much of it is related to spectroscopy
in fact the whole field of quantum mechanics is related to spectroscopy
quantum mechanics is a story that's contrived by human beings
to explain things that we really can't understand
I know when I was a student I was constantly struggling to try to relate this to things
that I knew from before
and you can't do that