Palabras para crecer

Defines levers, explains their functions, and suggests simple experiments to demonstrate how they work.

This entertaining book teaches young readers about the different body parts they use to move and play. Body parts are labeled on the photos showing how elbows, knees, ankles, and fingers bend.

La Geología es una ciencia sumamente atractiva ya que abarca cuestiones trascendentales relacionadas con nuestro planeta: su origen, su formación, la vida en tiempos pasados y los procesos actuales de evolución, en la que los seres humanos intervenimos de manera activa. En este volumen se analiza, además de su origen y formación, la estructura de la Tierra, la composición de la atmósfera, la deriva de los continentes, los volcanes, la formación del relieve, los glaciares, el mar, el ciclo geológico y los mapas.

People today refer to the Midwestern and prairie states as flyover country. During the Civil War, crossing those areas was the biggest obstacle in uniting the East and West Coasts of our divided nation. An act of Congress in 1862 authorized the Central Pacific and the Union Pacific railroad companies to build a railroad that would link the coasts. Seven years later, on May 10, 1869, an overwhelmingly immigrant labor force completed the task when a rail line was join in Promontory, Utah. The states had become united at last.