Audio Based Dictionary

America's Most Trusted Dictionary

Rhyming Dictionary and Thesaurus

A Research Guide for Students.

Definitions and examples of the mechanics and parts that make up the English language.

Offers a grammar hotline and a collection of reference materials.

Lung.org

Occupational Safety and Health Administration

Library of Congress Official Site

U.S. Government Publishing Office Official Site

This site features animated clips, an interactive timeline, other resources and helpful links.

All the battles are here, and a timeline is also included.

Find upcoming shows about things you're learning about, and more!

Lots of information on modern history.

Like the site says, the single best source for facts.

Learn about the women's roles in global history. This site feature, biographies, lessons, and essays.

For grades K-8, this site offers help in 25 topic areas!

Awesome math games and activities for students of all ages, parents and teachers alike.

Features definitions, propositions and interactive diagrams.

Get help with Algebra, Calculus, Geometry, and Trigonometry.

The world of Math online. It has tutorials and interactive practice activities and math preps.

Access math reference tables that you can view online or download and view on your computer.

Each day see an amazing different view of our universe, along with a brief explanation written by a professional astronomer.

Explore background information, educational material and published proceedings for a series of debates among leaders in the astronomical community.

Get a glimpse into the mysteries of our universe and learn about how its evolving and the various objects it contains.

Take a journey on the Highway through Time to learn how life began here on Earth then explore the Habitable Zone as you search for life within the solar system.

How has the science of astronomy changed since the early 1900s? Discover the history and revelations that occurred during the past century.

Learn all about NASA's 1969 Apollo 11 lunar mission including information about the crew, mission highlights, payload and more.

Explore online the major systems of the human body, including the skeletal, cardiovascular, endocrine, digestive, muscle lymphatic, nervous, reproductive and urinary systems.

Learn about the central nervous system through interactive games and activities.

Through online exhibits, explore phylogeny, the connection between all groups of organisms as understood by ancestor/descendant relationships.

Take a historical journey through the 1900s to explore treatments for various human behaviors, pioneers in the field as well as modern scientific discoveries.

Dissect a digital frog while learning the various parts of frog anatomy.

The title says it all! This is a very through site.

Have a question about Earth and/or water phenomena? Email it to professional geologists or search through the Frequently Asked Questions for more information.

Interesting Earth Science Pictures.

Regents Exam Prep Center for Earth Science. Questions, answers, explanations, old tests and more.

Volcano activity in Hawaii.

Shows phases of the moon in different positions around Earth.

From PBS Online: Using interactive models, explore the earth by simulating an earthquake or investigating a tsunami.

You guessed it: Tornados!

Extensive information and data on all aspects of earth and environmental sciences.

Discover the wetlands of the U.S.A. while learning about the creatures that inhabit these areas and what important resources are included in our nation's wetlands.

Activities for various science disciplines including energy, waves, heredity, ecology and much more.

This site unravels such mysteries as how a car engine moves a car and how refrigerators make things cold. New articles are added weekly.

This laboratory that never sleeps offers answers to a variety of scientific questions, as well as online activities, virtual tours and much more.

The latest weather research as well as the new ways weather information is being used to save lives and lessen property damages.

Discover the world of snow and ice including snow cover, avalanches, glaciers, and paleoglaciology.

Learn about the programs and resources of the United Nations agency dedicated to coordinating global weather predictions, air pollution research, and other climate related data gathering initiatives.

View pictures and an historical timeline of the greatest engineering achievements of our time.

Examine exclusive videos of the antlion (or "doodlebug") feeding behavior and metamorphosis, as well as information on how and where to find these creatures.