topic. They give you a little more of the story, such as how some famous physicist made a discovery or an unexpected real-life application of the point under discussion. You can skip these sidebars, if you like, without missing any essential physics.
The Technical Stuff material gives you technical insights into a topic, but you don’t miss any information that you need to do a problem. Your guided tour of the world of physics won’t suffer at all.
Foolish Assumptions
In writing this book, we made some assumptions about you:
You have no or very little prior knowledge of physics.
You have some math prowess. In particular, you know algebra and a little trigonometry. You don’t need to be an algebra pro, but you should know how to move items from one side of an equation to another and how to solve for values.
You want physics concepts explained clearly and concisely, and you want examples that let you see those concepts in action.
How This Book Is Organized
The natural world is, well, big. And to handle it, physics breaks the world down into different parts. The following sections present the various parts you see in this book.
Part 1: Putting Physics into Motion
You usually start your physics journey with motion, because describing motion — including acceleration, velocity, and displacement — isn’t very difficult. You have only a few equations to deal with, and you can get them under your belt in no time at all. Examining motion is a great way to understand how physics works, both in measuring and in predicting what’s going on.
Part 2: May the Forces of Physics Be with You
“For every action, there is an equal and opposite reaction.” Ever heard that one? The law (and its accompanying implications) comes up in this part. Without forces, the motion of objects wouldn’t change at all, which would make for a very boring world. Thanks to Sir Isaac Newton, physics is particularly good at explaining what happens when you apply forces. You also take a look at the motion of fluids.
Part 3: Manifesting the Energy to Work
If you apply a force to an object, moving it around and making it go faster, what are you really doing? You’re doing work, and that work becomes the kinetic energy of that object. Together, work and energy explain a whole lot about the whirling world around you, which is why we dedicate Part 3 to these topics.
Part 4: Laying Down the Laws of Thermodynamics
What happens when you stick your finger in a candle flame and hold it there? You get a burned finger, that’s what. And you complete an experiment in heat transfer, one of the topics you see in Part 4, which is a roundup of thermodynamics — the physics of heat and heat flow. You also see how heat-based engines work, how ice melts, how the ideal gas behaves, and more.
Part 5: The Part of Tens
The Parts of Tens is made up of fast-paced lists of ten items each. You discover all kinds of amazing topics here, like some far-out physics — everything from black holes and the Big Bang to wormholes in space — as well as some famous scientists whose contributions made a big difference in the field.
Icons Used in This Book
You come across some icons that call attention to certain tidbits of information in this book. Here’s what the icons mean:
Beyond the Book
In addition to what you’re reading right now, this book comes with a free access-anywhere Cheat Sheet for when you need a quick physics refresher on important constants and equations. To get this Cheat Sheet, simply go to www.dummies.com and type Physics I For Dummies Cheat Sheet in the search box.
Where to Go from Here
You can leaf through this book; you don’t have to read it from beginning to end. Like other For Dummies books, this one was designed to let you skip around as you like. This is your book, and physics is your oyster. You can jump into Chapter 1, which is where all the action starts; you can head to Chapter 2 for a discussion of the necessary algebra and trig you should know; or you can jump in anywhere you like if you know exactly what topic you want to study. And when you’re ready for more-advanced topics, from electromagnetism to relativity to nuclear physics, you can check out Physics II For Dummies.
Part 1
Putting Physics into Motion
IN THIS PART …
Part 1 is designed to give you an introduction to the ways of physics. Motion is one of the easiest physics topics to work with, and you can become a motion meister with just a few equations. This part also arms you with foundational info on math and measurement to show how physics equations describe the world around you. Just plug in the numbers, and you can make calculations that astound your peers.
Chapter 1
Using Physics to Understand Your World
IN THIS CHAPTER
Physics is the study of the world and universe around you. Luckily, the behavior of the matter and energy — the stuff of this universe — is not