"In the story of Rapunzel, the prince had to climb Rapunzel's hair to reach the top of the tower, but a pulley system would have been easier to use. Describes how pulleys work, and their uses. Includes a project to build your own pulley system and 'In the Real World' examples"--Provided by publisher.
Looks at how dams are designed, built, and improved with new technology. Includes audio, videos, activities, weblinks, slideshows, transparencies, maps, quizzes, and supplementary resources.
"In Cell Phones, readers will learn about the science and technology behind the development of the cellular phone. Vibrant, full-color photos and carefully leveled text will engage readers as they learn more about the challenges overcome to create the cell phone and how this super science feat continues to improve our communication with the world."--.