• Question: What is, in quantum mechanics, the uncertainty principle?

    Asked by anon-18007 to Cathal, Daphne, Darren, Jon, Katherine on 13 Mar 2012.
    • Photo: Katherine Haxton

      Katherine Haxton answered on 12 Mar 2012:

      It means that we can’t measure and know the precise position and momentum of a particle at the same time. If we make a really accurate measurement of a particle’s position, we can’t know its momentum very accurately at all, and the opposite is true too. It applies to really tiny things. If it applied to us, the world would be a strange place!
      Imagine if you were running around the football pitch, we could say exactly where you were, but not where you were headed and how fast. Or we could say where you were headed and how fast, but not where you were when we measured you.

    • Photo: Jon Benton

      Jon Benton answered on 13 Mar 2012:

      Katherine’s answer and analogy sum it up great so the only thing I’ll add is some history. It was published in 1927 by Werner Heisenberg a German physicist.

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