Watch these 10 short videos explaining what we all should know about the science of the Earth — how the planet's land, water, air, and life systems interact. The American Geological Institute has developed these videos to bring to life the core concepts identified by the U.S. National Science Foundation-funded Earth Science Literacy Initiative (www.earthscienceliteracy.org). For educational activities exploring each of the nine "Big Ideas of Earth Science" illustrated in the videos, visit Earth Science Week (www.earthsciweek.org). In Why Earth Science?, stunning video sequences and images illuminate the importance of knowing how Earth works and illustrate opportunities for careers in the Earth sciences.