Question: How does volcano's erupt?

Joanna Bryson answered on 20 Jun 2013:

I don’t know much about this, is there a geology zone? I think that the surface of the earth keeps moving around because it weighs different amounts (there’s different amounts & kinds of rocks in different places) and gravity from the sun & the moon keeps pulling on the heavy things, and then sometimes the crust of the earth gets weak & some of the soft molten stuff inside the earth breaks through & squirts out of a hole.