A geology lesson

Today on the way home from basketball, Tyler asked an extremely random question. At least I thought it was random, coming from a 5 year old. He said:
"Mom, what comes after all the rocks in the earth?"
I'm thinking....only my kid would ask this. But I do know the answer, thanks Mr. Stafford. It's lava.
So I answer, "Lava buddy"
Now you know that isn't sufficient
"Mom, what's lava?"
"You know buddy, what comes out of the volcanoes. It's melted rocks"
"Oh well, will it burn you pretty bad?"
"Yeah buddy it will burn you pretty bad."
"Oh okay, so kinda like what burned Annikan?"
A-ha - I knew it. Everything in my son's life relates to Star Wars somehow.
I figured that was the end of it. He was quiet for a while. Well by quiet I mean he was humming a Star Wars theme song - the one he claims is going to be for Episode 7.

Then "Mom, what comes after lava?"
Uhh....yeah mom what DOES come after lava. I thought I knew but I didn't want to be wrong so I told him I'd look it up later. So thanks to Google I'm happy to report that I once again know the layers of the earth and what they are made of:
crust
mantle - these two are the rocks (and did you know it's 1800 miles of rocks)
outer core - the lava
inner core

And in case you're really wondering what comes after lava - it's mostly solid iron. :)