The earth is round, so why don't some people hang upside down? The answer is gravity! With age-appropriate critical thinking questions and carefully leveled tex

Sound is made up of tiny vibrations. Learn how different vibrations create different sounds! With age-appropriate critical thinking questions and carefully leve

What kinds of solids can you see right now? Solids are a type of matter that is all around us. They can be heavy or weigh almost nothing. With age-appropriate c

What would happen if gravity didn't exist? People and objects would float into space! With this basic introduction to gravity, young readers will discover how g

Gravity from a New Angle is a comprehensive analysis of fundamental concepts in Physics. Concepts like force, work, power and energy were developed over a perio