How come lava is hot? – Extreme Speed Zone

Question: How come lava is hot?
- Keywords:
  heat,
  lava,
  temperature,
  volcano
Asked by cicely340 to Claire, Kate, Matt, Rob, Sam on 24 Jun 2013.
- Sam Geen answered on 24 Jun 2013:
  
  Lava is hot because of the pressure from the Earth’s crust pushing down. I’m sure Matt has a better answer, so I’ll let him expand on this.
- Matthew Pankhurst answered on 25 Jun 2013:
  
  As you go deeper into the Earth there is more pressure (more and more rocks on top), which means there is more temperature. So, the deeper you go the hotter you go. Lava comes from the really hot parts that are so hot they melt, and like a hot air balloon they rise up through the rock and come out. The surface isn’t nearly so hot because it doesn’t have much rocks on top – none! The heat at the surface comes from the sun. So basically, lava is hot because it comes from a hot place!

Question: How come lava is hot?