Bartleby.com (American Heritage dictionary of the english language -physics)

Center for International Earth Science Information Network

Earth Science World-Gateway to the Geosciences

Earth Science Virtual Library

Enviromental Sciences InfoSurf

NASA's Earth Science Enterprise

Nobel E-Museum

Optic Links

OSTI-Office of Scientific and Technical Information

Physics.com

Physics InfoSurf

Physics Web

Science / Technology Virtual Library-ECHO (exploring and collecting history online)

Yahoo: Astronomy

Yahoo: Earth Sciences

WebStars: Astrophysics in Cyberspace