автор: Logan

Invariant Variational Principles …

In January 2009, Barack Obama became the 44th president of the United States.  In the weeks and months following the election, as in those that preceded it, countless social observers from acros …

As the State moves to solidify its control over the solar system, it suddenly finds itself at war with a new enemy. The new colony on Mars prepares for a struggle for survival against a harsh world a …

Three hundred years ago, humanity was nearly wiped out by a natural disaster. Now, it threatens to destroy itself. By the year 2409, the State has been rotting from the inside for centuries. Its dest …

A chance meeting in the University of North Carolina campus library in 1944 began a decades-long friendship and sixty-year correspondence. Donald Justice (1925–2004) and Richard Stern (1928&nda …

When was the last time you looked to the night sky and wondered what might be looming in the far reaches of the universe? These are the tales of the planets, aliens, and creatures-of what we call sen …

Connect students in grades 5 and up with science using Atmosphere and Weather. This 80-page book covers topics such as heat absorption, relative humidity, barometric pressure, measuring wind, and int …

Connect students in grades 5 and up with science using Rocks and Minerals. This 80-page book covers topics such as the layers of the earth, mineral identification, igneous rocks, sand, and fossils. I …

Connect students in grades 5 and up with science using Sound. This 80-page book includes subject-specific concepts and terminology, inquiry-based activities, challenge questions, extension activities …

Connect students in grades 5 and up with science using Light and Sound: Energy, Waves, and Motion. This 80-page book reinforces scientific techniques. It includes teacher pages that provide quick ove …

Connect students in grades 5 and up with science using Geology: Rocks, Minerals, and the Earth. This 80-page book reinforces scientific techniques. It includes teacher pages that provide quick overvi …

Connect students in grades 5 and up with science using Meteorology: Atmosphere and Weather. This 80-page book reinforces scientific techniques. It includes teacher pages that provide quick overviews …