El Pacto Del Mayflower /

Explains The Early History Of How The Bill Of Rights Came To Be And How It Is Used To Protect Citizens.

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

Read about fall activities and learn about the cycle of seasons in this Spanish-language edition. Full-color photographs and a photo glossary make this a great introduction to nonfiction reading for children.

Acompaña a Geronimo y ayúdale a salvar un bosque y... ¡el planeta entero! Por medio de una divertida historia de Geronimo, iremos descubriendo curiosidades sobre nuestro planeta, pero no sólo eso, sino que también aprenderemos datos curiosos y, lo más importante, cómo salvarlo.

What is work? You may think work is doing chores or going to a job, but you do work every time you move something from one place to another. With experiments that demonstrate these fundamental concepts, discover how you work, and how simple machines make doing work easier.

An asteroid hitting Earth may sound like science fiction, but it is a real danger. This book explores what the different scenarios might be and how we can prepare ourselves in case such a disaster should occur.