Dave David, age 10, of Mason, Michigan, for his question:

How do they make the lead for pencils?

The so called lead inside a lead pencil is not made by human hands. It was created by ancient forests and processed by the patient earth. And it took more than 200 million years to finish the recipe. The basic ingredients were scraggly trees, mosses and ferny foliage. Ages ago, they flourished in forests that grew in soggy swamps. The old vegetation fell into the stagnant water, but there were none of the bacteria that cause dead plants to rot.

So the old vegetation could not decay. It time the earth remodeled the scene. The swamp dried up and the fallen forest was covered with new layers of dirt and heavy rock. It was buried and crushed, heated and changed. After long ages, only the carbons and a few other ingredients were left and the old forest became shiny black coal. If coal stays buried a few more million years, only the carbon is left    and it becomes soft, sooty graphite. And graphite is the so called lead inside a lead pencil.