This page's description of the various kinds of radioactivity includes some discussion of the history of its discovery, illustrations, and hot links to related sites.

A+ Click is an interactive collection of more than 3700 math problems and answers for K-1 K-12 school program. It defines the personal level of math knowledge. You move up into the next level if you give 5 correct answers in a row. Practice makes perfect.

ARKive is a collection of photographs, videos, and fact-files illustrating thousands of species of animals, with emphasis on the International Union for Conservation of Nature and Natural Resources (IUCN) Red List of endangered species, and on species found in Britain. For each animal there are approximately 10 minutes of video footage, 6-10 still photos, and sound recordings (where appropriate), creating a complete profile of the species' characteristic behavior and appearance. The images are accompanied by a page of facts, including taxonomy, a physical description, conservation status, geographic range, habitat, and other information. There are also links to other animals with related taxonomic families, habitats, or conservation status.

This two-day lesson helps students understand abiotic and biotic factors. Once the concept has been grasped, they can trace the interactions of these factors within a system.

Includes information about the Academy of Natural Sciences educational programs: teacher resources, information for planning field trips to the museum and women in the natural sciences.

This page is from a comprehensive and comprehensible tutorial in physics. Schematic drawings, questions for understanding with the answerers, and links to animations are included.

This lesson describes how amino acids build proteins in a person's body. Amino acids are the chemical building blocks for the structure of an organism. A link to a quiz is provided at the end of the lesson to check comprehension.

This online manipulative features a virtual balance scale. It offers students an experimental way to learn about solving linear equations involving negative or positive numbers. The applet presents an equation for the student to illustrate by balancing the scale using blue blocks for positive units and variables and red balloons for negative units and variables. The student then works with the arithmetic operations to solve the equation. A record of the steps taken by the student is shown on the screen and on the scale. The applet reinforces the idea that what is done to one side of an equation must be done to the other side to maintain balance. Instructions for using the applet, background information about solving equations, and teaching suggestions are included.

This lesson from Algebra Lab demonstrates "how to write equations of quantities which vary inversely." The lesson includes an example of a graph of this type of equation, and several example problems. This supporting material would be best used following some in-class instruction explaining how to solve inverse variation equations.

The American Association of Amateur Astronomers (AAAA) is intended to foster interest in amateur astronomy by developing and promoting programs for its membership and the amateur community at large in the areas of observational astronomy and electronic communications on the internet. The AAAA's web site features links to membership information, news releases, and announcements of astronomical events and organizational activities. Educational materials include a tutorial on the solar system, an introduction to the constellations, a history and introduction to astronomy, and a link to the Arp Atlas of Peculiar Galaxies. There is also an FAQ feature, a link to the organization's newsletter, links to partner organizations, and information on products available at the AAAA online store.

The American Mathematical Society's (AMS) Books Online makes available full text of over 30 scholarly monographs published by the AMS, covering a range of subjects including algebra and algebraic geometry, analysis, applications, differential equations, geometry and topology, logic and foundations, mathematical physics, number theory, probability, and general interest. Their gateway page organizes titles by subject and author.

This database provides access to information on every crystal structure published in the American Mineralogist, the Canadian Mineralogist, European Journal of Mineralogy, and Physics and Chemistry of Minerals, as well as selected datasets from other journals. The data are searchable by mineral name, author, chemistry, cell parameters and symmetry, diffraction pattern, and a general search. There are also lists of minerals represented in the database and authors of publications cited.

This page features information for students who wish to pursue careers in physics. Topics include academic preparation for middle school, undergraduate, and graduate/postdoctoral students, biographies of physicists working in various specialties, and articles profiling physicists working in industry.

The Amoeba Sisters strive to facilitate curiosity and engagement by making biology both humorous and meaningful. The videos use real world examples and silly cartoons to demystify difficult biology concepts, such as cell anatomy, homeostasis, enzymes, and biomolecules. A new video is released weekly. The creators are sisters who both work in education. One is a high school biology teacher who found these videos made biology more approachable and easier to comprehend.

The Andean Botanical Information System (ABIS) provides information about the flowering plants (phanerogams) of Andean South America. Materials include information on the environments of the Andes Mountains and a gallery of images of plants (by family) distributed in the Andes of Peru and Chile. There is also information on a research database that provides access to collection-label data of South American Andean plants for taxonomic purposes. The specimen-label information from over 7500 collections from coastal Chile and Peru have been electronically captured and are available in checklists. Other materials include a biography of J. Francis MacBride, who performed groundbreaking research on the flora of Peru, a bibliography of additions to the Andean flora, and information on related resources. The site is available in both English and Spanish.

This collection contains animations of a nuclear chain reaction, nuclear fission and nuclear fusion. It also showcases interactive models of the first atomic bombs and simulation of the "Nuclear Winter" effect.

With more than 29 million cubic kilometers (7 million cubic miles) of ice and snow, the Antarctic Ice Sheet is so massive that its weight depresses the underlying crust by 900 meters (nearly 3,000 feet). New snow that collects on the ice sheet's surface causes the ice beneath it to spread out and move along the slope of the land. In this video segment adapted from NOVA, a team of glaciologists carves into one glacier on the East Sheet to monitor the nature and speed of its movement.

This web site provides information on apple snails (family Ampullariidae), the largest living freshwater snails on earth, often kept as aquarium pets because of their attractive appearance and size. Topics include the care of apple snails, their anatomy, species and genera, and information on snail pests, embryology, and genetics. There is also a frequently-asked-questions feature, photos, links to web sites and literature, and an online discussion forum.

For some, the word archaeologist brings to mind Indiana Jones, the hero of four action-packed adventure movies. While Indiana Jones may have some things in common with real archaeologists, the differences far outweigh the similarities. Rather than relic hunters and adventurers, NSF-funded archaeologists are scientists, whose work is aimed at answering key questions about the past, answers that may even inform policy about contemporary problems such as how societies adapt to climate change, ecological shifts, political upheaval or mass migrations. They work as far afield as the Aleutians, Egypt, China and the deserts of the Southwest, or as close as Mississippi.

This printable sheet is an excellent reference tool for geometry students. It details the formulae for finding the area, volume, and surface area for a variety of two- and three-dimensional shapes and includes an illustration of each that shows which measurements are important to the calculation. Presented are: areas of polygons (square, rectangle, parallelogram, trapezoid, circle, ellipse, triangles); volumes of polyhedra (cube, rectangular prism, irregular prism, cylinder, pyramid, cone, sphere, ellipsoid); and surface area (cube, prism, sphere).