Imagine the Universe is dedicated to discussion about the universe, how it is evolving, and the kinds of objects and phenomena it contains. The site is intended for students age 14 and up and is a service of NASA's High-Energy Astrophysics Science Archive Research Center (HEASARC). Contained within this site are explanations of the concepts and principles used to study and understand the universe, ... Full description.

This activity and demonstration teaches the concept of parallax (the apparent movement of an object caused by a change in the viewer's position) and relates the concept to a real-world astronomical event, ­the discovery of Pluto. It employs the Blink Comparator, an online simulation illustrating the technique used by Clyde Tombaugh to discover the ninth planet on February 18, 1930. Full description.

In this lesson, students observe a teacher-directed demonstration that provides a conceptual understanding of latent heat, the "hidden heat" present in all changes from one phase to another, by using a hand warmer. Full description.

This site describes snow crystals and snowflakes. Although a common meteorological phenomenon, snow crystal growth is a fascinating and poorly understood process, in which remarkably complex and beautifully symmetric structures appear, quite literally, out of thin air. The many facets of snow crystals are described here, along with the attempts to understand their formation. Site highlights include ... Full description.

This resource covers basic astronomy, Newtonian mechanics, the Sun and related topics (weather, electromagnetic waves, nuclear energy), and space flight. The material stresses space applications, history, and intuitive content, and includes a brief refresher course on algebra and trigonometry. It is also available in Spanish. Full description.

This site provides a non-mathematical introduction to the magnetism of the Earth, the Sun, the planets and their environments, following an historical thread. It is also available in French, Spanish, and German. Full description.

This non-mathematical, self-contained exposition of studies of the Earth's magnetic environment in space covers such topics as magnetism, electrons, eons and plasmas, the radiation belt, the sun and the solar wind, exploring earthspace, the dynamic magnetosphere, auroras, and interplanetary field lines. Many of the topics introduce the user to the related physics and astronomy, and are thus a useful ... Full description.

Simscience is a website devoted to areas of science where computer simulations are at the forefront of discovery. This interactive activity aids students in understanding structures (particularly dams), fracture mechanics, engineering, hydraulics and geotechnology. This site emphasizes analytical thinking, iterative design, multiple solutions and teamwork. Learning in this activity is mostly collaborative, ... Full description.

Surf Your Watershed is the Environmental Protection Agency's effort to provide a comprehensive center for geographically relevant information about drinking water regulations, drinking water publications, public water systems, ground water, and water quality and pollution issues. Resources include how to locate your watershed anywhere in the United States, state and tribal information, an index of ... Full description.

The purpose of this project is to present the holistic study of the biosphere using remote sensing technology. The intention is to have students perceive the biosphere as containing interlinked environments and organisms, an ability which would later aid students when they are introduced to concepts like trophic levels and energy flow within an ecosystem and in the biosphere. It is also expected that ... Full description.