THE FREE PHYSICS TEXTBOOK

How do objects and images move? How can animals move? What is motion?

How does a rainbow form? Is levitation possible? Do time machines exist? What does 'quantum' mean? What is the maximum force value found in nature? Is 'empty space' really empty? Is the universe a set? Which problems in physics are still unsolved?

Download the text (21st edition, December 2007) here.

This site provides a free physics textbook that tells the story of how it became possible, after 2500 years of exploration, to answer such questions. The book is written for the curious: it is entertaining, surprising and challenging on every page. With little mathematics, starting from observations of everyday life, the text explores the most fascinating parts of mechanics, thermodynamics, special and general relativity, electrodynamics, quantum theory and modern attempts at unification. The essence of these fields is summarized in the most simple terms. For example, the text presents modern physics as consequence of the notions of minimum entropy, maximum speed, maximum force, minimum change of charge and minimum action.

Puzzle of the month:

Each of two identical closed glass containers contains five bees. In one container all the bees are flying, in the other, they are all at rest on the floor. Which container shows a larger reading on a weight scale?

 
For each field of physics, the text presents the latest research results, the best animations, the best images, the most interesting physical puzzles and the most telling physical curiosities. It includes more than 550 animations and illustrations, more than 100 tables and more than 1600 challenges and puzzles.

Written in English, over 1500 pages are provided for students, teachers, and for anybody who is curious about the precise description of nature. To satisfy even the most extreme curiosity, the text ends by exploring the limits of time and space, and the wonders that can be discovered there.

Motion Mountain is downloaded over 30 000 times a year. It aims to be among the best introductory physics texts available. Do you have an idea for improving it? Add it to the suggestion wiki! For a valuable suggestion, I will add you to the sponsor and acknowledgment list, or send you a reward. The first 360 pages are available in the French language, and 80 pages are available in the Spanish language.

Since May 2007, this project is supported by the Klaus Tschira Foundation.