Professional associations and societies are good places to find information about specific fields. Generally, these are organizations of people in a particular field. Many associations and societies, however, have good outreach and education programs to provide information to people who are interested in the topic but not professionals. There are thousands of such societies worldwide. This list includes some of the larger societies.
For a big list of science societies, covering every science field that you can imagine—and, probably, a few beyond that (for example, the Nigerian Dwarf Goat Association)—go to the Internet Public Library’s list of Science and Technology Associations: www.ipl.org/div/aon/browse/sci00.00.00.
General Science
The American Association for the Advancement of Science: www.aaas.org
National Science Foundation: www.nsf.gov
Royal Society (United Kingdom): www.royalsociety.org
Physical Sciences
American Chemical Society: www.acs.org
American Institute of Physics: www.aip.org
American Physical Society: www.aps.org
Royal Society of Chemistry (United Kingdom): www.rsc.org
Biological Sciences
American Institute of Biological Sciences: www.aibs.org
Federation of American Societies for Experimental Biology: www.faseb.org
Earth and Space Sciences
American Astronomical Society: www.aas.org
American Geological Institute: www.agiweb.org
American Geophysical Union: www.agu.org
American Meteorological Society: www.ametsoc.org
International Astronomical Union: www.iau.org
Technology and Engineering
IEEE (originally the Institute of Electrical and Electronics Engineers): www.ieee.org
International Technology Education Association: www.iteaconnect.org
