Motion is a change in an objects position. This fascinating title explains in a clear, simple way how objects are moved by a change in energy. Simple activities show young readers how energy is changed by applying a force, either by coming in contact with an object or by a force that does not touch it physically, like gravity.

Marking the 100th anniversary of World War I, this series takes a detailed look at the course of events in the Great War and the conflict's lasting impact on the world. Includes documents, artifacts and first-person accounts that will help young readers relate to the subject, as well as informative sidebars, short biographies, fact boxes, timelines and stimulating text-dependent questions that will keep readers engaged and motivated. Simultaneous.