# Special Relativity Modules

Most introductions to special relativity misstate what Einstein said in his 1905 paper, obscuring the beauty of the theory and making facts like time dilation and length contraction seem mysterious and hard to believe. By carefully stating the two principles Einstein started with, and working through their logical consequences with simple "spacetime diagrams," we come to see time dilation and length contraction as natural and easy to believe - indeed, it would be an odd universe were these to not occur! By considering accelerated observers, we follow one of Einstein's amazing thought experiments that helped lead him to the idea that gravity might have something to do with "warped" space and time, creating a springboard to his general theory of relativity. As with the quantum mechanics lectures, the focus is on the ideas: gaining substantial insights into the fascinating physics involved, with as little mathematics as possible.

The special relativity lectures have been divided into 14 modules, listed below, each with a title and a brief description of its content. It is recommended that these be viewed in the order listed, as each module builds on concepts introduced in previous modules. Clicking on the titles below will reveal an active link to the recorded lecture segment that includes a list of key learning outcomes.

## SR-1: Spacetime Diagrams

An introduction to spacetime diagrams – a first step towards understanding Einstein’s special theory of relativity.

## SR-2: Spacetime Diagrams for Sound Travelling in Air

Drawing spacetime diagrams of simple thought experiments involving sound in air as a warm up exercise for light in vacuum.

## SR-3: The Doppler Shift for Sound

Continuation of a thought experiment from SR-2, leading up to a derivation of the familiar Doppler shift for sound in air.

## SR-4: Einstein’s Speed of Light Principle ("Principle 2")

Repeating the experiment from SR-3 using light rather than sound, and understanding what Einstein assumed regarding the speed of light.

## SR-5: Einstein’s Relativity Principle ("Principle 1")

Einstein’s Relativity Principle applies to both mechanical and electromagnetic phenomena.

## SR-6: Doppler Shift for Light

Deriving the Doppler shift for light, from which all of special relativity follows.

## SR-7: Minkoskian Geometry

Space obeys the rules of Euclidean geometry. Spacetime obeys the rules of a new kind of geometry, called Minkoskian geometry.

## SR-8: Applications of Minkowskian Geometry

Learning to use Minkowskian geometry to understand, very simply, a variety of aspects of Einstein's spacetime. including how a light particle experiences space and time during its journey from one place to another.

## SR-9: Synchronization of Clocks

A discussion of how to synchronize clocks that are separated in space, and how this leads to the relativity of simultaneity.

## SR-10: Coordinate Axes and Length Contraction

A discussion of the space and time axes of a moving observer and an introduction to length contraction.

## SR-11: Simultaneity and Length Contraction

A continuation of the SR-10 discussion on length contraction. Resolving Principle 2*.

## SR-12: Einstein’s Rotating Disk Thought Experiment

Introduction to Einstein's famous rotating disk thought experiment, which he used to help him understand the true nature of gravity.

## SR-13: Artificial Gravity Provides Hints about Real Gravity

Analyzing the artificial gravitational field inside a rotating cylinder to discover hints about the nature of real gravitational fields.

## SR-14: The Curved Geometry of a Rotating Space

The spacetime diagram of a rotating Bob is analyzed, leading us to conclude that his spatial geometry is curved.