John Chapman, age 9, of West Vancouver, British Columbia, Canada, for his question:

Do volcanoes stretch to the center of the globe?

Nobody knows exactly how deep they go. But experts are quite sure that they do not go down as far as the center of the Earth. Some think that their roots may go down as far as 30 miles. A car can go this far in half an hour. The center of the Earth is almost 4,000 miles straight down under your feet. It takes a week or so to drive this distance.

We are told that the center of the Earth is fiery hot. But this seething mixture does not erupt from a volcano. Its lava comes from a pool of melted rocks in the solid crust of the earth. The deep core cannot erupt because billions of tons of heavy material keep it sealed down there, hundreds and hundreds of miles below our feet. If you study more about the Earth, later in life you may help the experts to learn exactly how deep down a volcano can stretch.