Duke 
Hipótesis, teoría, ley [PDF ebook] 
Hypothesis, Theory, Law

Expanding on our popular Let’s Explore Science series, this book focuses on Hypothesis, Theory, and Law. All three of these are important in the process of scientific inquiry, which is the way scientists study the natural world. As they explore, they develop explanations based on what they learn from their work. By forming a hypothesis, testing and evaluating theories, and describing the laws that exist in chemistry and physics, students will learn all about this important science topic. This book will allow students to learn that cause and effect relationships are routinely identified and used to explain change.