• Question: Which element do you think will run out first?

    Asked by aisha4509 to Dilwar, Lou, Rachel, Simon, Susan on 19 Nov 2013.
    • Photo: Simon Langley-Evans

      Simon Langley-Evans answered on 19 Nov 2013:

      Tricky question there Aisha. There are some elements that are becoming much harder to find, mine and extract. Helium is one and we discussed it in another answer to a question. The rarest element is astatine, which is a radioactive element that is very short-lived. Nobody has got a good sample of it together, because in a mass, the radioactivity makes it so hot that it vaporises.

    • Photo: Louise Brown

      Louise Brown answered on 20 Nov 2013:

      Hopefully not Oxygen! I have no idea though! Something we use a lot of I suppose!

    • Photo: Susan Skelton

      Susan Skelton answered on 21 Nov 2013:

      Hello aisha4509!

      This is a really interesting question!
      Most of the elements on Earth are stable elements – that means they never disappear. Even if they are all used to make something, they are still in the same form afterwards, so we can always recycle them and use them for something else!

      For example, a lot of precious metals like silver and gold are used in electronics, like in our phones and computers. But when our computer breaks, we can always recover the metals from inside and use them to make something else: anything from a more technologically-advanced computer to a gold ring!

      However, having said that, there are some elements which are radioactive. That means that over time, they decay and form new elements. When this happens there is not as much of the initial element anymore, and we will never get it back.

      The three main radioactive elements present on Earth are uranium-238, potassium-40 and thorium-232. Scientists think that the radioactive decay of only these three elements produces half of the total amount of the Earth’s geothermal heat! (That is the heat that comes from the centre of the Earth.)

      Potassium-40 has the shortest lifetime out of these three elements: about 1.3 billion years. However, we are using more and more of Uranium-238 for fuel in our nuclear power stations. So, personally, I guess that Uranium will run out first, but it is hard to predict these things as things might change in the future.

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