Explore the four levels of impact that invasive species can have. Several different invasive species are featured in this overview of the impact an invasive species can have.

Earth's magnetic poles have reversed themselves throughout its long history. Find out what scientists know about these reversals. A geologic time line shows when the reversals occurred.

This resource provides a summary of the Clean Water Act and sections such as background, federal and state responsibilities, regulations, enforcement, and major amendments are provided.

This is a wonderful way to explore the US Constitution. The actual text of the Constitution comes first, then an excellent explanation of the text follows. In addition, most of the Amendments have essays by scholars on opposing sides of judicial interpretations, so students can understand some of the legal conflicts that arise around the Constitution. Students can also perform a keyword search, explore by topic, and search the text by Supreme Court decisions.

Understand the characteristics and features of Earth's core from this detailed article. Includes high-quality illustrations, a downloadable poster, a video, and links to other resources.

Information about the digestive system, why digestion is important, how food is digested, and how the process is controlled. Includes a diagram of the body parts involved.

Site explains the federal law that was passed in 1990 that protects Native American cultural items: the Native American Graves Protection and Repatriation Act(NAGPRA). The site answers FAQ on the NAGPRA and keeps online databases of artifacts and human remains.

Using light as our measuring stick in space, science site provides all types of fun facts using light years and seconds as a reference.

A fantastic resource for learning about how ice cores are collected, the information we can learn from them about Earth's climate history, the types of research being done with them, and how they are stored. Includes lots of videos.

Explains why passing the puck in ice hockey is such an important skill. The puck is an example of a velocity vector and vectors can be added to determine the direction and speed of the puck. [4:28]

Engine power is constrained at superspeedways like Daytona and Talladega, so teams use aerodynamics to gain an advantage. Teams adjust their cars to minimize drag, but then it's up to the drivers to find 'the draft' and to trust the drivers behind them to literally "bump" them into Victory Lane. [5:29]

Find a wealth of scientific information on the status of biodiversity in the world today, the threats it faces, and why it is critically important to preserve it.

This concise site that provides an explanation of what producers are along with a short quiz to test your knowledge of producers and consumers.

Potty-Mouth Pete is trying to spread bad netiquette all over the Internet. Can Clicky, Webster, and Nettie stop him before it's too late? [6:45]

Sara and Finn are finding out how light travels. Join them, and learn the nature of light energy.

Nettie and Webster teach new friends about how to be an upstander and how to deal with cyberbullying. [5:24]

Nettie and Webster make their way through Ad Alley and find out that staying focused on a single task while online can be tricky... and getting distracted has consequences.

Describes experiments students can do to investigate the sense of smell. The experiments target either grades K-6 and 3-12.

This site from The History Place provides a timeline of American history between 1784 and 1790. Mentions many famous people and events of the era. Links to John Adams, Thomas Jefferson, Samuel Adams, James Madison, the Constitution, Bill of Rights, George Washington (and his inaugural address), the Northwest Ordinance, and Federalist Papers as well as to other timelines surrounding this period.

Learn about this document that charted a government for the Northwest Territory. View the complete text and images of the original document.