Although the proliferation of teaching resources on the Internet is extensive, little is known about these materials’ use or utility. The Visionlearning project is a multiyear effort to design and evaluate web-based interdisciplinary science teaching resources. The Visionlearning resources are modular in nature and integrate text, simulations, news, history, and interactive exercises into a comprehensive overview of scientific concepts. Students using these resources in a traditional college science course scored significantly higher on a standardized assessment quiz than students who used a printed textbook. Those students who reported frequent use of the website scored better than their classmates who reported less frequent use. This research demonstrates that well designed web-based learning materials can significantly improve science education.