[Disclaimer Sound]
[Channel Intro]
"Heisenberg Uncertainty Principal"
This brings us to the Heisenberg uncertainty principle.
In our quest to understand how small things can get.
We need to know if there is a measure
of size below which we can't go.
We see from our little thought experiment
that as a wave a particles location is not fixed the....
__waves spread out.
Here, we see, three different
wave packets or an electron.
The wave packet at the top is narrow and therefore easier to locate.
But it is less than one wavelength so its
momentum is impossible to figure out.
The bottom wave packet contains plenty of
wavelength information but it is quite spread
out and its location is more uncertain.
Wave packet in the middle has enough wavelength
information to make its momentum less uncertain....
And it is less spread out than the one on the
bottom making its location less uncertain.
But due to the spread out nature of matter
waves we still can't know both the locations
and momentum at the same time.
Mathematically stated the uncertainty in position
times the uncertainty in momentum....
....is always greater than or equal to
Planck's constant divided by 4π. This is
the Heisenberg uncertainty principle.
It has nothing to do with the accuracy
of our instruments and everything to
do with the wave nature of matter.
_A_
Good way to illustrate this is to look at an
electron in an energy well too deep for it to get out.
But remembering that the electron has a
wave function that gives the probability
of finding it at any given point and....
....some of those points....
....admittedly with very low probability....
....can be found outside the walls of the well
as if it had tunneled through the wall.
When in fact, it did not.
This tunneling effect is the basis for
scanning tunneling microscopes or....
....STM for short here's an
'STM at the Max Planck Institute'.
It has a small pinhead that is actually one single atom at its tip.
The tip is brought close enough to the object
for electrons to tunnel across the space exactly
in accordance with Schrodinger's equation.
This creates an electric current as....
....the tip scans across the object the
current will go up or down depending on
whether an atom is under the tip or not.
This is repeated over and over
till the entire surface is mapped.
What we are doing is actually feeling the surface
and the object to see and measure the atoms.
"The End"
[Channel Outro]
