In Primary School, probably (I doubt it would be Infants School), we were taught that beneath our feet lay molten rock all the way to the core, which was itself molten.
“Look down,” our teacher said, “down there is rock that’s so hot it’s melted.”
Changed our lives. When we gave it a second’s thought, it was both fascinating and frightening.
Now, of course, knowledge has grown and science is much more sophisticated. Under our feet isn’t hot, molten rock, like lava. It’s still hot, but has the colour of grey and the consistency of chewing gum. A thickish low viscosity goo that sinks to the core (solid) then rises, and as it does it moves the continental and oceanic plates around.
Occasionally it gets thrust up into the atmosphere. Here’s some, which shows that torturous journey and fascinates me every time I think about it, which these days is often.
To think those rock layers were once quite happily resting horizontally.