• Question: what is the smallest thing that we can see with a nacked eye

    Asked by amun to Austin, Kirsty, Nike on 21 Jun 2012.
    • Photo: Nike Dattani

      Nike Dattani answered on 21 Jun 2012:

      We can see things that are about 0.1 millimeters long … which is about the thickness of thread.
      If you have good vision you should be able to see things of that size without glasses, but you’ll likely only notice them if they are black and on top of a white piece of paper, or white and on top of a black background.

    • Photo: Kirsty Ross

      Kirsty Ross answered on 22 Jun 2012:

      Actually it is possible to see things that are even smaller than that!

      Have you ever sat inside on a sunny day with the curtains partly closed? The beam of sunlight that shines into the room will often illuminate dust particles. Dust particles can be made of pollen, human skin, soil, fibres, soot and moulds. The average dust particle is between 2 and 4um. This is equal to 0.002 to 0.004mm. So your eyes are pretty good at seeing very small things. Anything smaller than this would probably require a magnifying glass or microscope.