Absolutely amazing image galleries, activities, and feature articles. Lets you see the world REALLY close up.
A repository of information on all things earth-related: satellite images, reference, web-basedd experiments, and featured stories on things like volcanoes, cities at night, natural hazards, and ecological controversies.
This is a really fun and useful website. You can search it for articles about how things work -- in everything from science and computers to business and gardening. There's also a weekly newsletter and "fact of the day."
London's Science Museum's hugely entertaining (and educational) site lets you learn about scientific properties while trying to manuver a spring through an obstacle course. Multiple levels for different ages. You can also create your own obstacle courses and share them with friends.
Very cool website for learning about -- and tracking -- hurricanes and typhoons.
Very cool web-based periodic table that lets the user look at the elements through the screen of various disciplines and scientific angles. For example, you can see the periodic table in a biological context, or geology. You can also see the elements in terms of their orbital properties, isotopes, or allotropes. Nice!