HowStuffWorks Science has explanations and colorful illustrations related to earth science, life science, and other wonders of the physical world.

The Molecular Expressions website features hundreds of photomicrographs (photographs through the microscope) of everything from superconductors and high-tech materials to ice cream and beer.

The National Library of Medicine (NLM), on the campus of NIH in Bethesda, Maryland, is the world's largest medical library. It collects materials in all major areas of the health sciences and to a lesser degree in such areas as chemistry, physics, botany and zoology. The collections stand at 5 million items--books, journals, technical reports, manuscripts, microfilms, photographs and images. Housed within the Library is one of the world's finest medical history collections of old (pre-1914) and rare medical texts, manuscripts, and incunabula.

Educational and entertaining items pertaining to physics, the mathematical sciences, and to mathematics in general.

The Physics Classroom is an online interactive tutorial of basic physics concepts. The lessons use an easy-to-understand language to present common physics principles discussed in a first-year high school physics course.

This is a page in The Physics Hypertextbook. It is a work in progress.