"Los invisibles"

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

Alexander Graham Bell was always trying to invent new things! In this biography that has been translated into Spanish, readers will learn about Alexander's life as a teacher and inventor of such incredible inventions as the telephone, record player, and metal detector. Colorful images, supportive text, an interesting timeline, and a helpful glossary, table of contents, and index combine to give readers an inspiring look into the life of Alexander Bell.

An illustrated survey of the history and customs of the native North Americans who were members of hundreds of different tribes with varying lifestyles over the centuries.

There is a contest at a school to design a new playground. The students use blocks to build their models. As they build, they use three-dimensional shapes. Some students build a train out of blocks for the younger students to play on. Can you guess which three-dimensional shape they use for the train's wheels? Read to find out which design wins.