El dragón de Komodo

Readers won't have to disassemble their favorite toys to discover what makes them work. This book explores electric, magnetic, and motion-powered toys from design to function. It introduces readers to the six simple machines and explains how they use force and motion to do work. Not every toy is a technological marvel. Readers learn about time-honored favorites including the rocking horse, Slinky, and rattles.

Who were the earliest Americans? When, how, and from where did they enter and spread across the continent? And what is their relationship to modern Native Americans? Anthropologists develop theories to answer these questions based on the evidence they discover. Their theories—and the discoveries that prove and disprove them—are highlighted in this fascinating volume, full of awe-inspiring facts and incredible breakthroughs. Readers will feel like anthropologists and archaeologists themselves as they read about bones and artifacts, and what they reveal about the ancient cultures that roamed...

Viven 4 gusanos en el árbol, el pastel de cumpleaños tiene 4 velas... “Yo tengo 4 años”. Este libro es una forma muy especial de celebrar el cuarto cumpleaños de los más pequeños. Con él aprenderán a decir su edad de manera lúdica y divertida, ¡y podrán demostrar a todo el mundo que ya son mayores!

Discusses the role of the gases surrounding Earth and the relationship of the atmosphere to weather. Presented in English and Spanish.