Sunday, August 08, 2010

Big Downer! Gravity in Action: Rollercoasters! by Joan Newton

Most of the time we think of gravity as a static law of nature. It's just sort of there when we need it--on the downside of a long uphill climb--or sometimes when we don't, as when we drop our favorite mug onto the tile floor.

But what more dramatic example of the basic principle of gravity in action than the roller coaster, an amusement park ride that thrills us as it avails itself of the stored energy waiting for that long, heart-pounding drop?

Joan Newton's Gravity in Action: Rollercoasters! (Amazing Science) (PowerKids/Rosen Publishing) combines skillful book design, typesetting, dramatic full-page color photos, and a brisk but simple text to describe the history, science, and fun of this favorite amusement park diversion in a way that will attract primary grade students to master this principle of physics.

Newton begins her exploration of coasters with their history--going back to thirteenth-century man-made sledding hills and explaining the grandaddy of the roller coaster, the "Russian Mountain," a tall wooden platform which riders climbed to enjoy the long, waxed slopes down which wheeled trains of cars careened on special tracks. The first American "coaster," true to our practical nature, evolved from a coal track down a mountain: mules pulled wagons up to the top, were loaded on one wagon while the rest of the wagons were filled with mined coal, and the mules, drivers, and payloads enjoyed a thrilling ride down the tracks to the bottom. Some early P.T. Barnum-type saw the potential in this feature and turned the "gravity railroad" into a tourist attraction when the coal seam was exhausted. Soon entrepreneurs saw the possibilities in this idea and began to construct their own wooden mountains, making sure the the first hill generated enough momentum to carry the train of passenger cars through lesser ups and downs all the way to the finish.

In her next chapter, the author discusses the principle of turning "stored energy," (well-muscled runners in the starting blocks, the cars of a roller coaster at the top of the first hill) into "working energy."

Energy is everywhere. We use energy every day. A roller coaster uses two kinds of energy--stored energy and working energy. Stored energy is the energy an object has when it is still. Working energy is the energy an object has when it's in motion.

A coaster at the top of the first hill has stored energy. Gravity pulls it down, setting it in motion. This changes the stored energy to working energy.

With the basic science in mind, Newton moves on to explain the sorts of energy used to propel the coaster up that first long incline, describing modern rides utilizing air, water, chemical, and electromagnetic power to "load" the energy into the device for its long exciting run. In the final chapters, "Record-Breaking Coasters" and "A Big Thrill," dramatic photos of the rocket-powered Kingda Ka, the world's tallest and fastest at 128 mph, located in the United States, the Steel Dragon, world's longest (1.6 kilometers), and one phenomenal Japanese ride that takes its passengers through fourteen loops!

Backed up with a glossary which defines all the boldfaced terms introduced in the text and a full-page index, Gravity in Action: Rollercoasters! (Amazing Science) is an eye-catching and appealing introduction to the principles of basic elementary school science. This title is only one in Rosen Publishing's Amazing Science series for primary readers.

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