What is nanoscale?

What is the smallest object we’re able to see with a microscope? Here, we explain how we can use electrons to make microscopes powerful enough to make individual atoms visible.

You might wonder how we can use particles, such as electrons, to replace the waves of light normally used in a microscope. As Leonardo says in the video, particles can be thought of as having a wavelength. In fact, in some circumstances (such as in our electron microscope) they behave exactly like waves rather than as particles. We can even calculate a particle’s wavelength, (lambda):

[lambda = frac{h}{m_ev}]

Here (h) is planck’s constant – a very small number which sets the scale for the quantum world (6.63 x 10^-34 m²kg/s), (m_e) is the mass of the electron, and (v) is the velocity of the electron.

This all sounds very unlikely; how can something be both a wave and a particle? This isn’t what we see at the scale of the everyday world around us. Since this is the only physics we ever experience directly, our brains understand the world in terms of the distinct particles and waves we observe. However, this results from the fact that the world we see around us consists of large numbers of particles carrying a substantial amount of energy. This is the domain of so-called classical physics – the kind we are most familiar with.

At the scale of individual particles there is really no difference between particles and waves. Whether we see an electron behave more like a particle or a wave depends on exactly what it is doing at the time.