How Do You Measure Time?

Provides an overview of the design, uses, weapons, and equipment of U.S. Navy submarines. Written in English and Spanish.

Mysterious ancient ruins, hidden deep in the jungle of southern Mexico In May 1840, explorers John Stephens and Frederick Catherwood road their mules along a steep, muddy jungle path. They were hoping to find the ruins of an ancient, deserted site in Mexico they knew only from visitors’ accounts. Through the trees, they spied the remains of a crumbling stone palace. Palenque! In the weeks they spent there, the men discovered intricately designed buildings and mysterious glyphs, or symbols. Who built this city? What did the glyphs mean? The questions remained largely unanswered until the...

The plot of The Empty Region takes the reader from the military camps of holy warriors in Pakistan, to the security corridors of the CIA and the FBI. It’s a fascinating puzzle inhabited by historical characters, including Osama bin Laden and George W. Bush, as well as officials aware of the tragedy´s secrets. Szichman leads us along the terminals where the air pirates of al-Qaida consummated their tragic ritual, makes us travel on the airplanes, turned into guided missiles, and recreates the 102 minutes when the burning towers of the World Trade Center became hell on earth. Although...

María no puede ir al colegio porque tiene mucha tos. Sus padres trabajan, así que la solución es contratar a Gerda como canguro. Pero, lo que María no entiende es que sus padres la hayan elegido. ¿Es que nadie se da cuenta de que es una bruja? Un libro que refleja la importancia de no dejarse llevar por las primeras impresiones.

This book gives students an in-depth look at how large telescopes work. The wonder and awe of space and the scientific instruments we use to study it both come shining through in this fascinating book. Full-color diagrams and illustrations will help students visualize how the technology of telescopes works. Students will learn about the creation of mirrors 8 meters wide and telescope teams that work together to create a telescope as powerful as if it had a mirror the size of the Earth!