Where do the bubbles come from in a piece of cake? Why do triangles make a structure stronger? And how come magnets don't stick to the wall? This colorful and straightforward introduction to the physical sciences gives young readers an easy-to-understand overview of such concepts as materials, forces, structures, solids, liquids and gases. Explanations are accompanied by simple, fun activities, including building a structure out of dried spaghetti and inflating a balloon with a gas made by combining vinegar and baking soda. Parents and teachers will find more explanations, activity ideas and a helpful glossary in the back.