But the neat thing about electrons is that
we can manipulate them,
as we saw with those magnets.
We can speed them up and slow them down. We
can change direction.
We can change the wavelength of the electron
beam.
And if we make it small enough, we can use
electrons to see very small things.
We can make an electron microscope.
An electron microscope sort of on this bench
here.
We could use that to take pictures down towards
the level of molecules.
Let's see what we do.
So here is a picture of a pin head that's
been taken with an electron microscope.
It's still recognisable to you as a pin.
And if we go in and look in more detail, you
can see bacteria on the surface of the pin.
You can also see the grooves in the pin where
it's been ground.
And let's go in still further.
Well here they begin to look like fish fingers.
We haven't yet got to the level of molecules.
Now with more sophisticated versions similar
to this sort of device
nowadays we can take pictures like this,
right the way down to the level of atoms.
And here we have, what looks like a mountain
canyon.
Sheer cliffs. Those cliffs are probably hundreds
of atoms high.
So if you were an atomic mountaineer you could
climb up and down them.
But what's really wonderful is that now we
can take movie images and zoom in.
We can pretend that we've got atomic spectacles
and we're going to go on an atomic plane ride.
And travel around and see this is a sheet
of copper seen from above
with atomic spectacles.
Let's see what shows up on our plane ride.
So we start gradually moving in and we see
these canyons flying beneath the plane.
You can see marks on the surface,
but for the moment let's concentrate on those
huge cliffs.
Just like the Grand Canyon.
Now away from the cliffs, what to our eye
appear to be smooth surface,
we see here there are atoms on there and gradations.
It looks somewhat like flying around above
the clouds in a regular plane.
And this thing coming up looks like the vortex
of a tornado
but it's just where one or two atoms are missing.
That sort of thing.
So you're seeing here the surface of what
to your eye appears to be smooth
but with atomic spectacles you see has got
incredible structure.
Now the real power is that once you can see
individual atoms like this,
it gives you the possibility to move them
around,
put them in special places where you want
to.
And here some scientists at IBM in the States
have gathered together some iron atoms
and put them one by one in a circle.
But what's really interesting in this picture
is what's going on in the of that circle.
What we're looking at here is the surface
of copper.
Now copper is a conductor, the electrons swim
around freely.
But once they're trapped inside this circle
and can't get out, they form waves.
Just like if you filled up a plastic or styrofoam
cup with coffee
and dragged it across the floor, it would
set up waves on the surface.
They're called crispations one of the words
I've used in doing these lectures.
This is the analogue at the atomic level.
You're seeing electron waves set up in this
ring of iron atoms.
And that's the key. These are the electron
waves.
By manipulating the electrons, we can change
the length of those waves.
We can make them smaller and smaller.
And go and see smaller and smaller things.
The only thing that limits us is how much
energy we put in to those electron beams.
To make the waves smaller and smaller.
All I have to do is make a larger electron
microscope.
