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Microgravity: living on the International Space Station
Microgravity: living on the International Space Station

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2 An introduction to quantum science

Traditionally, science has been broken down into the disciplines of biology, chemistry, Earth sciences, physics and astronomy, which are usually linked to the scales in Figure 2:

  • Biology and Earth Sciences, from animals, including humans, down to DNA
  • chemistry on the scales of atoms and molecules
  • astronomy for large-scale planets and stars
  • physics for the rest.

Nearly 50 years ago, Richard Feynman (Figure 3) gave a lecture on the subject ‘There’s plenty of room at the bottom’. In it he said: ‘[based on] the problem of manipulating and controlling things on a small scale … it is a staggeringly small world that is below.’ (RSC, n.d.).

A black and white photograph of Richard Feynman.
Figure 3 Richard Feynman (1918–1988), the American theoretical physicist.

But below what? Well, the quantum world is on the scale of atoms and smaller. From Figure 2, you can see that these scales are less than 0.000 000 000 000 01 m (10–14 m). Do you think there any devices in your household that work on this small scale?

Well, in most households there are CDs, DVDs and blu-rays. How are these read though? These discs are read using LASERs (Light Amplification by Stimulated Emission of Radiation), which use quantum effects. You will learn more about LASERs later on this week. Then, if you have a PC or laptop with a solid-state drive (SSD), this relies on solid state physics, which also relies on quantum effects. Modern digital televisions have plasma screens. Several years ago, TV screens were effectively particle accelerators with huge screens!

You will now look at properties of waves, starting with diffraction.