This the Volcano World site from the University of North Dakota.  There are interactive games for the students, teacher lesson ideas and helpful information, and virtual field trips to volcanoes.

Part of the Discovery site, this is the grossest site out there, as they say.  It is an interactive site with information for students about gross science.  This includes some games, information about the body, and information on worms and roaches.

This is a site devoted to bubbles.  They have information on how to make bubble formulas and bubble skills.

Jefferson Lab has teacher and student resource pages.  There is also a section on interactive games and puzzles.  Many of the games are based on Science and Math.

This is the educator's site for NASA.  There is a lot of information about the solar system, Earth, the planets and the sun.  They also have contests for teachers and students.  The site also contains links to live digital TV, streaming videos, video conferences and much more.

This is a teacher/student page for the Monterey Bay Aquarium.  They have live webcams, videos, activities and games.

This site contains information about space and the Solar System.  This information can be accessed in English and Spanish, and it can be accessed at 3 different levels (basic, intermediate, and advanced).  There are Java games, facts, virtual tours, and an online journal.

This free virtual tour of the International Space Center is great for students in grades 5 - 8.  Students can participate in a variety of activities focusing on life-sciences and NASA educational products.  It does require a download to make everything work, but it is free.

This site has information about the Hubble Telescope.  There are video lectures, streaming videos on different topics, interactive games, educational information, galleries and more.