Lava flow races

Volcanic eruptions occur when magma in the Earth’s mantle forces its way through holes or cracks in the crust. Once magma has been erupted from a volcano it is called a lava flow. Lava is very hot, up to 1200 °C.  When the lava is at the surface it begins to cool as it flows. As lava cools, it begins to change from a runny liquid to a more sticky mix of liquid lava and solid rocks and crystals. As the lava continues to cool, small crystals will grow and form lumps of solid rock which are carried by the lava. Once fully cooled and solidified rock will be left behind.