• Question: Why is lava so hot?

    Asked by omg123 to Matt, Maia, Lyndsay, Liam, Dionne, Brendan on 12 Nov 2018.
    • Photo: Liam Taylor

      Liam Taylor answered on 12 Nov 2018:

      Lava is just melted rock! Imagine temperatures being sooooo hot that rocks start melting! :O It’s hot because it has come from inside of the Earth, where temperatures are over 1000°C (and as high as 4000°C in the very middle). We’re stood on a very thin bit of cooled rock called the crust – most of the Earth is actually a big ball of hot liquid rock.

    • Photo: Matt Bower

      Matt Bower answered on 12 Nov 2018:

      As Liam says, it’s because it comes from inside the Earth where it’s very hot. The heat mainly comes from the decay of radioactive minerals over millions of years.

    • Photo: Dionne Turnbull

      Dionne Turnbull answered on 12 Nov 2018: last edited 12 Nov 2018 11:54 pm

      I’ll never complain when it gets above 30°C in the lab again 😉

    • Photo: Brendan Marrinan

      Brendan Marrinan answered on 13 Nov 2018:

      Lava is magma that has come to the surface. Magma is incredibly hot because it comes from beneath the surface of the earth where temperatures are higher.

      A geothermal gradient exists beneath the surface (it gets hotter the deeper you go) which is about 25-degrees for every 1km.