• Question: how many atoms are in one keyboard block

    Asked by beep362bat to Sameed, Jose, Joanna, Heidi, Freya, Chris on 18 Nov 2019.
    • Photo: Jose Brandao-Neto

      Jose Brandao-Neto answered on 18 Nov 2019: last edited 18 Nov 2019 10:18 am


      This one a protein crystallographer is well qualified to answer πŸ™‚ Protein crystals are kinda like plastic because proteins are made out mostly of carbon, just like plastics. See my answer in the 5 steps below (Note that I used APE – answer, prove, explain πŸ˜‰ )
      .
      One protein has about 10,000 atoms and if they’re organised in the vertices of a cube 10nm in size, that would be a realistic model for a crystal (100,000 nm make up a milimetre!).
      .
      each key in the keyboard I’m using is 10mmx10mmx4mm in size
      .
      .
      So, given:
      .
      1) DENSITY_nm3=10,000 atoms in a volume 10nmx10nmx10nm (1000 cubed nm) (note the units).
      Rewriting: DENSITY_nm3=10,000atoms/1000nm3
      Rewriting for compatctness: DENSITY_nm3=10atoms/nm3
      .
      2) KEY_VOLUME_mm=10x10x4 cubed mm
      Rewriting for compactness: KEY_VOLUME=400 mm3 (note the units!)
      .
      3)Changing units:
      KEY_VOLUME_nm3=10mmx10mmx4mm=1,000,000nm x 1,000,000nm x 400,000nm
      KEY_VOLUME_nm3=400,000,000,000,000,000 nm3 !!
      .
      4) ATOMS_IN_KEY=DENSITY x VOLUME
      Being specific: ATOMS_IN_KEY = DENSITY_nm3 x KEY_VOLUME_nm3 = 10 atoms/nm3 x 400,000,000,000,000,000 nm3 = 4,000,000,000,000,000,000 atoms
      .
      .
      #######
      ## APE
      #######
      .
      5)At the beginning I ommited that protein crystals are actually 50% protein and 50% water. Water is mostly oxygen, which is kinda like carbon, too, so get the result in 4) and double it! so a decent estimate for the number of atoms in a key in a keyboard is a whopping 8,000,000,000,000,000,000 atoms πŸ™‚

Comments