The Space Place: Why is Earth rotating?
Dr. Marc of NASA's Space Place provides an overview for children of Earth's rotation and how our period of rotation is changing.
New Science: The First Day of Spring
NASA Kids shares a brief explanation of the changing day length through an exploration of the seasons for children The site includes an animation of the seasons and vocabulary definitions.
The Astronomical Applications Department of the U.S. Naval Observatory presents a wealth of background information and data concerning astronomical events, calendars, rise and set times of the Sun and Moon, lunar phases, and more for the adult audience.
Earth and Moon Viewer is an interactive program that allows children and adults to view Earth daylight darkness distribution from a variety of viewpoints. Visitors can manipulate location and time of viewing. The basic map can be found at this site.
The American Museum of Natural History presents background information, activities, data, and resources for educators to facilitate investigations of the extended day length in Antarctica.