• Question: How do you work with molecules if we can’t see them with a microscope?

    Asked by Diegoperezsanz to Max, Francis on 6 Mar 2018.
    • Photo: Max Jamilly

      Max Jamilly answered on 6 Mar 2018:

      Awesome question. I think about molecules every day and I know they exist, but they are very difficult to see. I have to design experiments which detect many molecules at once or detect signals from these molecules, like temperature or glowing light.

      We can, in fact, see molecules with many different kinds of microscope. Search for “atomic force microscopy benzene” – you’ll see pictures of a single molecule with just 6 carbon atoms! And we can see much larger molecules like proteins using X-rays.

    • Photo: Francis Man

      Francis Man answered on 6 Mar 2018:

      Seeing individual molecules is very hard (although it has been done recently and the images are spectacular). BUT, most scientists don’t work with single molecules but with very large amounts of them.
      In practice, most of the molecules I use are either in the form of powders (often white, but sometimes very colourful) or transparent liquids. There are many ways to check that they are pure (meaning that we are working with a single type of molecule, but in large numbers).

      By hand, the smallest amount of solid you can handle and weigh is about 1 mg, but even that can represent billions of molecules. If you dissolve it, you can handle much smaller quantities.

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