Examine the natural forces of gravity and friction that are constantly at work on Earth. Then discover the principles and forces that govern moving objects and how we use them to our advantage. Includes four feature segments. Facts About Forces; Presents the law of universal gravitation and the forces of static and kinetic friction. Laws of Motion; Introduces Sir Isaac Newton's three laws of motion and the principles and forces that govern moving objects. Rotation and Revolution; Examines some of the different ways time can be measured, including sidereal and solar time, along with why Earth has days and nights. How We Fly; Looks at how jet engines, wing design, and special building materials allow airplanes to take to the skies.

Teacher's guide available under additional info tag.