• Question: what creates convection?

    Asked by sebisepic to Jen, Jill, Mel, Phil, Stef on 19 Mar 2013.
    • Photo: Jennifer Paxton

      Jennifer Paxton answered on 19 Mar 2013:

      I think convection is caused by the differences in density of air. In cold air, the air particles are quite close together and become dense and so falls ( kinda like it is heavier). When air warms up the particles space out more and the air becomes less dense ( lighter) and rises. The difference between these is what makes the convection currents -so if you imagine a radiator the air above that is warm and so rises. Eventually this air gets far away from the heat source (radiator) and becomes cold and so falls. Once it heats up it rises and so on……

    • Photo: Stefan Piatek

      Stefan Piatek answered on 22 Mar 2013:

      Wonderful answer Jen, another good way to see it is to look at peas in a simmering pan, if the heat is low the peas will start off in the middle, reach the top and be pushed to the sides and then drop down.

      That’s because the middle is where the heat is, so they rise, then are pushed by the next peas below them and have to go to the side. The side is cooler so they then drop down.

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