We just learned a little about LEDs
Let's learn about Lava!
Lava is molten (or melted) rock!
To melt rock, the temperature has to be over 1,200 degrees.

(from: wikipedia - lava)
The word lava is also used for the cooled down lava that turns into rock.

(from: wikipedia - lava)
Kid Facts - Blast from the past: ENIAC