This animated slideshow introduces biodiesel as a fuel alternative. With concern about the use of petroleum-based fuels at an all-time high, biodiesel is experiencing a popularity surge. And algaeâotherwise known to some as pond scumâ are grabbing headlines as the next potential biodiesel superstar. But how and why do algae make oil? And why do they make so much of it? In this audio slide show, U.C. Berkeley's Kris Niyogi describes the process and its potential.

This interactive exposes students to Earth's atmospheric gases of oxygen, carbon dioxide, and ozone. As the user manipulates the interactive to increase or decrease the concentration of each gas, explanations and images are provided that explain and visualize what the Earth would be like in each scenario.