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Language: en

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TOM: I am with Kate Oliver and Andy Collins

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from the Centre for Functional Nanomaterials
at the University of Bristol.

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And they're going to show me how we see tiny
tiny tiny things.

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KATE: So we're nanotechnologists, and for
us, a tiny thing is an atom.

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TOM: Right. Okay.

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KATE: So we have one way of seeing atoms.

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It's called a scanning tunnelling microscope.

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And it uses the fact that if you bring a tip
close to a surface,

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there's a probability that because of quantum
--

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TOM: I love that explanation.

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KATE: -- the electrons will go from the
surface to the tip.

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So basically, as you move the tip along,

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if you hit a bump, more electrons will tunnel
up into the tip.

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And that will give you an idea of how close
the surface is.

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TOM: But that means you need a tip that is
one atom thick.

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KATE: It means you need a tip that is very
small.

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TOM: Okay. Which is where you come in.

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ANDY: So I'm going to show you how to make
a tip that's one atom thick.

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You need to get it as sharp as you possibly
can for good imaging.

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We've got a secret weapon of nanoscience:

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Pliers. And wire cutters.

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TOM: I kind of assumed there'd be some kind of

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hideously expensive equipment required in
this, but...

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ANDY: So I've got some platinum wire.

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TOM: Okay, that is hideously expensive.

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ANDY: It's a platinum iridium alloy.

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And we use platinum so that it doesn't conduct oxygen,

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which would make the tip fatter.

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Because we want one single, conductive atom
at the surface of the tip.

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So if I hold that wire in my pliers,

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and I apply the wire cutters at a 45 degree
angle...

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..there we go!

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That means you've got something that, in theory,
is atomically sharp.

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TOM: That's fantastic. So what do you do if
it's not conductive?

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Because quantum tunnelling only works with
something that's conductive.

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KATE: This is an atomic force microscope.

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TOM: It's really cool! And it's actually scanning
at the minute?

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KATE: It is. You can see on the screen here,
that is -- 20 micrometres across.

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So that is about a fifth of the width of one
of your hairs, Tom.

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But we wouldn't be able to see anything on here

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if it wasn't against a really flat,
high-contrast background.

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Luckily, we have a number of minerals that
come in convenient flat sheets.

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One of these is mica, which I have here.

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But we can't be sure that we've only got one
layer on the surface.

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So for that, we have another
high-tech nanoscience tool.

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TOM: Which is sellotape.

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KATE: Yes.

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Adhere this down.

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And it's stuck to just one of these layers
of mica, or maybe a couple.

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TOM: But the top layers?

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KATE: Yes.

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And then: peel it off, and can you see the
faint outline?

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TOM: There is. There is a faint outline of
a square on there.

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Which is -- is that just a one atom thick
layer of mica?

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KATE: Yep. And that implies that what's left
is also entirely flat.

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Giving us a really good contrast for any atoms,
molecules, species --

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these are some fibres we've got on top of
this surface --

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that we want to have a look at and see what
they can do for us that's really useful.

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TOM: So we have million-pound equipment 
around this lab.

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And then we've got pliers and sticky tape.

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ANDY: Yes.

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TOM: That is wonderful. Kate Oliver, Andy
Collins,

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from the Centre for Functional Nanomaterials
at the University of Bristol.

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Thank you very much, guys!

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