Earth Exploration Toolbook (EET): is a collection of online Earth system science activities. Each activity, or chapter, introduces one or more scientific data sets and analysis tools that enables users to explore some aspect of the Earth system
Edheads: provides engaging web simulations and activities for kids. Current activities focus on simulated surgical procedures, cell phone design (with market research), simple and compound machines, and weather prediction.
Field Book Project: intends to create a "one stop" archive for field research journals and other documentation. You can find plenty of examples from actual field research journals for your classes.
Minds-On Physics Learning Resources: promotes lifelong learning in physics and pedagogy for science teachers at the upper secondary level through offering a range of modelling tools based on existing commercial and non-profit solutions, as well as the outcomes of previous related Leonardo projects.
Periodic Table of Videos: a wide array of videos about the elements and other chemistry topics
PhET Simulations: provides dozens of fantastic simulations for physics, chemistry and biology. The website also includes a collection of teacher contributed activities, lab experiences, homework assignments and conceptual questions that can be used with the simulations.
Physics Education Resource Guide: is a collection of general physics education resources, study physics resources, physics teaching resources, physics practice tests and quizzes, physics games and simulations, physics podcasts,physics blogs and physics publications.
Planting Science: to connect your middle or high school students to science mentors and a collaborative inquiry project.
Understanding Science: provides a fun, accessible, and free resource that accurately communicates what science is and how it really works.