Relativity: Do I need to know about it? What will I learn here?

Einstein's Special Theory of Relativity is centrally important to our understanding of time, space, matter and energy and it is one of the great examples of creative and analytical thought. So perhaps you will find it interesting to understand some of its central ideas. Although some of the consequences of the basic ideas may seem counter-intuitive, the ideas themselves are not particularly difficult to understand, as we hope to show you.

What will I learn?
This presentation explains some of the key ideas in relativity and how they lead to its important results. Although it is presented in a simple way, it concentrates on the physics, rather than the history.

For whom was this production made?
Someone who would like to understand and who doesn't mind concentrating and thinking for a while. Someone who will ask "Why?". Because of links, this production works at several different levels, and so it can serve users with a range of backgrounds and expectations.

The presentation level
(the multimedia modules) is qualitative and simplified. It does not presuppose a knowledge of physics. It has no mathematical derivations. Yes, it does have a couple of equations, but you'd be disappointed if we left out E = mc², wouldn't you? More than that, we hope that you will want to know not just what that equation means, but why it means that — where it comes from. The modules run for a minute or so each. Because of this, some of the explanations are brief and the simplifications are severe. For that reason:

The links
mainly go to further explanation of the points mentioned in the presentation level. Many of them are at a simple level and are designed just to take more time to explain some of the subtle points that are rushed over in the presentation level. Some are more detailed and more demanding. Pursue them as far as you like. If you don't like equations, watch for the maths and no maths* icons.

Will I understand relativity after this? The presentation level is only a brief explanation of some of the ideas and a keen user/reader will, we hope, understand these at one level. When you finish, there is a quiz to test your understanding. The links take you deeper (and deeper) into relativity and we hope to interest you to go further. If you become really interested, a textbook for first year university physics is a good place to continue. These books usually have a good introduction to relativity, including problems to solve.

Understanding comes in a range of levels. There is a limit to what one can learn about swimming from watching or reading: at some point you have to get into the water. So it is with physics: real physical understanding can be tested by solving problems using that understanding. Doing experiments brings a further level of insight. And yes, deep understanding does require the maths. (See Richard Feynman's quote about mathematics in explanations.)

Nevertheless, you can appreciate Bach without being able to follow a fugue,
   And Shakespeare can enjoy without the need
   For recognising five iambic feet,
so we hope that this presentation will help you appreciate the simplicity and elegance of the Theory of Special Relativity. Please give it a try.