• Question: What is the smallest AND coolest thing you have ever seen under a microscope?

    Asked by Super Sam to Sally S, Becky P, Lorelei R, James L, hannahbaird, Eva S, elaineho, dimonavidenlieva, angharad on 17 Mar 2026. This question was also asked by ados532meed78.
    • Photo: Hannah Baird

      Hannah Baird answered on 17 Mar 2026:

      I use a very powerful microscope which is much bigger than the benchtop microscopes you might have seen in films/on TV/in school, so the smallest thing I’ve seen is single molecules moving around on a membrane. I personally think that seeing such tiny things interact with each other is really cool, but I’m not sure others would share my enthusiam!

    • Photo: James Lazenby

      James Lazenby answered on 18 Mar 2026:

      That’s a great question and I’ve seen lots of really cool things under a microscope. When you picture a microscope you’re probably thinking of a light microscope. These microscopes use light (i.e. photons) to visualise the specimen. We are therefore limited in how small a thing we can see based on the wavelength of the light and the way that light interacts with the particles in between the specimen and the microscope. The smallest thing we can see with a light microscope is theoretically about 200 nm. If you look at a ruler and see the smallest measurement this will likely be 1 mm. Divide that by 1000 and you get 1 µm. Divide that again by 1000 and you get 1 nm.

      However, we can go smaller than this using a range of techniques. My favourite being one with the fun name STORM. Imagine your twinkling Christmas tree lights. Each light looks different because it is separated by the other lights by the sequence in which they turn on, but if you were to record those Christmas tree lights and then merge all the times the light blinks on into one image it would look like a rope instead of individual lights. That’s similar to what STORM does but on a much smaller scale. With this technique we can visualise down to 20 nm and I have been able to see individual virus particles on the surface of cell.

      The other microscope type is what is called an electron microscope. Electron microscopes use electrons to visualise the sample and electrons have much shorter wavelengths so can see much smaller things. They also operate in a vacuum so you have no interference from anything in between your specimen and your microscope. it is possible with an electron microscope to see 0.1nm and people have been able to see clusters of atoms.

      The coolest thing I have seem was much bigger than that. If you ever see a fly’s eyes under a microscope they are fascinating.

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