Pack just enough to fit. Crews determine what personal items to take with them on a trip to Mars. Each team must decide what to take with them on a two-and-a-half year trip to Mars and whether their items will fit within the allotted...

This article explains what Earth Day is and why it was founded. It also presents criticisms of the holiday. Includes suggestions for things we can all do to take care of the Earth.

This article is an in-depth description of the first Earth Day, and includes the impact the demonstration had on the environmental movement.

Overview provides fun facts, goals of the founders, special initiatives, and general information about Earth Day.

Beautiful photos of our planet in celebration of Earth Day. Includes video.

[Free Registration/Login Required] This Article-A-Day-Set provides six articles related to "time." Students will learn about the days of the week and months of the year.

Learn your part in keeping unused items out of landfills by organizing a yard sale. By exchanging or donating your old stuff you can save money and reduce the amount of waste that goes into landfills!

Each year, people throw out millions of tons of food that could still be eaten. That is a lot of food! Even when we compost food waste there are still some negative impacts. Resources like water and energy are used to grow and transport...

Winter solstice, earliest sunset, latest sunrise. It seems that, in the Northern Hemisphere anyway, these three events should happen on the same day. Read this explanation of the changing of the seasons and learn why the winter solstice...

To those of us who live on earth, the most important astronomical object by far is the sun. This article explains how the motion of the sun through our sky cause day and night, the passage of the seasons, and earth's varied climates.

The large fireball observed on the morning of Feb. 15, 2013, in the skies near Chelyabinsk, Russia, was caused by a relatively small asteroid that entered Earth's atmosphere at high speed and at a shallow angle. Preliminary information...

Wind is air in motion. It is produced by the uneven heating of the earth's surface by the sun. Since the earth's surface is made of various land and water formations, it absorbs the sun's radiation unevenly. When the sun is shining...