Through diagrams, hands-on experiments, and biographies, this book introduces earthquakes, a shaking or trembling of the ground when rocks along a crack in Earth's surface suddenly shift.

An illustrated introduction to the study of air pollution, providing facts and information on the causes of air pollution, the ozone layer, climate change, and related topics; and including air pollution brain teasers and instructions to perform a related experiment.

"Presents information on simple machines with a focus on wedges. Explains what a wedge is, how wedges work, and includes examples of past and present uses. Intended for third to fifth grade students"--Provided by publisher.

"Presents information on simple machines with a focus on screws. Explains what a screw is, how screws work, and includes examples of past and present uses. Intended for third to fifth grade students"--Provided by publisher.

"Presents information on simple machines with a focus on inclined planes. Explains what an inclined plane is, and includes examples of past and present uses. Intended for third to fifth grade students"--Provided by publisher.