• Question: How do we know what DNA and subatomic particles etc. look like - is it possible to get that far inside the specimen and actually see the structure of them?

    Asked by cancer to Lilly, Francesca, Deepak on 12 Mar 2014.
    • Photo: Francesca Day

      Francesca Day answered on 12 Mar 2014:

      That’s a very good question! Subatomic particles are so small that it’s completely impossible to see them directly, so they don’t look like anything at all! We know they exists from lots of different kinds of experiments though.

      For example, Rutherford discovered that atoms had a nucleus by shooting alpha radiation particles (helium nuclei) at a sheet of metal. He found that some of the alpha particles bounced straight back to him, so he concluded they must have bounced off a small, positively charged nucleus of the atoms. So he was able to know that the nucleus existed without having to see it 🙂

      There are also special kinds of microscope for looking at very, very small things. For example, an electron scanning microscope uses electrons instead of light. You can get pictures of DNA with an electron scanning microscope, so it’s sort of like seeing DNA! (DNA is much bigger than subatomic particles!).

    • Photo: Lilian Hunt

      Lilian Hunt answered on 12 Mar 2014:

      I think Francesca’s nailed the answer to this one! Google some electron scanning microscope images of DNA and other things, they look really cool but you’ll notice they’re not in colour because they don’t use light to see them.

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