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The science bit

Here you can explore some of the science behind nanotechnologies:

What is the 'nanoscale'?

A nanometre is a millionth of a millimetre, a billionth of a metre.

Nanotechnology is usually referred to as working with materials at between 1 and 100 nanometres in size, however this has not been properly defined yet and sometimes people use 1-300nm as the definition of nano. Scientists argue a lot about this stuff, but it matters because it has an implications for safety, for regulation and for research. What really matters is what size the properties change, not particularly the size when that happens.

Viz Lab Image Scaler

There is an image scaler that lets you see the amazing difference between human scale and
nano scale.

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The nano effect...

Scientists are interested in the nanoscale because when we get down to these tiny sizes, many materials start to behave in different ways. They are sometimes much stronger, or conduct more electricity, opaque substances can become transparent, solids become liquids at room temperature or insulators become conductors. This is often down to the change in their surface area when they are used at this tiny scale.

The Surface Area Thing

The Surface Area Thing is what makes nano really interesting - that is the surface area to volume ratio - and it gets talked about a lot in nanotechnology. But what on earth does it mean?

What is the surface area?

Well, the surface area of an object is the amount of surface it has and the volume is a measure of how much space it takes up. When we talk about the ratio between these two things, we are comparing how much of each quantity it has.

Why's that interesting?

In a nanoparticle, the amount of surface area the particle has is larger compared to its volume. This means there are more atoms on the surface of the particle than in the middle of it, and that makes them the most important. Surface atoms act differently to atoms inside a particle, so when there are more surface atoms than inside atoms the way they behave dominates the whole behaviour of the particle.

The opposite is also true, when the particle is bigger it has a large volume compared to its surface area and the number of atoms inside the particle is much higher than the number of atoms on the outside (the surface) of the particle. What the inside atoms are doing is the most important thing and the behaviour of the particle will be decided by them.

So what difference does it make?

How surface atoms and inside atoms behave can be very different. This means that when we get a very small piece of material, with comparatively large numbers of surface atoms, the material can act very differently to what we are used to (aluminium nanoparticles explode!). In nanotechnology we are making use of particles with lots of surface atoms and the fact that this makes them behave differently – it allows us to do new and exciting things.

What counts as a ‘nanotechnology’?

Any technology that makes use of the properties of atoms and molecules at the nanoscale or is able to observe and manipulate at the nanoscale is a nanotechnology. In fact, it is one of the few research areas that overlaps physics, chemistry, biology, medicine and engineering.

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