Here are all of my sources. If you would like more information, go to some of these sites. All diagrams are designed by Jonathan Morgan Petrini (me).
http://www.eia.gov/kids/energy.cfm?page=2
http://www.nbcnews.com/id/43786480/ns/technology_and_science-science/t/radioactive-decay-fuels-earths-inner-fires/
http://www.classzone.com/books/earth_science/terc/content/visualizations/es0702/es0702page01.cfmchapter_no=visualization
http://www.eia.gov/kids/energy.cfm?page=2
http://www.nbcnews.com/id/43786480/ns/technology_and_science-science/t/radioactive-decay-fuels-earths-inner-fires/
http://www.classzone.com/books/earth_science/terc/content/visualizations/es0702/es0702page01.cfmchapter_no=visualization