Grammar check and simple explanation of 'volcano' for a 6-year-old

Correct sentence: A volcano is a hole in the Earth's crust where hot lava can come out.

Why this is better (short):

1. Only the first word is capitalized: write "A volcano" instead of all caps.
2. We add "the" before "Earth's crust" because it is the specific crust that covers Earth.
3. Using "can come out" sounds natural and correct for something that may happen.

Simple explanation for a 6-year-old:

1. The Earth's outside is like a hard skin — that is called the crust.
2. Under the crust it is very hot, with melted rock inside.
3. When the hot rock pushes through a hole, that hole is a volcano and the hot rock that comes out is called lava.
4. Lava cools and makes new rock. Volcanoes can also make ash and gas.
5. Volcanoes are powerful, so people should stay far away from them.