PBS
Pbs Nova: Relativity and the Cosmos
This well-written explanation of relativity includes animations and pictures which may be helpful in understanding a tough topic.
Libre Text
Libre Texts: Physics: Distortion of Space and Time
If the speed of light remains a constant then time and distance change. Oh, it can be confusing! This text will help clear up the confusion. Discussion questions should serve to reinforce comprehension.and exercises
Georgia State University
Georgia State University: Hyper Physics: Special & General Relativity
This site from the Georgia State University provides an interesting chart form of the ideas of relativity. Column 1 - Idea, Column 2 - Experiment. Each item is linked to its own page of explanation, which is well done. A nice type of...
University of St. Andrews (UK)
University of St. Andrews: Special Relativity
A historical approach to special relativity, giving all the events and names in the history of discovery of special relativity. Many links to these individuals.
University of St. Andrews (UK)
University of St. Andrews: General Relativity
A somewhat labored but thorough explanation of general relativity, beginning with Aristotle. Many links to the personalities connected to the article.
Cosmo Learning
Cosmo Learning: Fundamentals of Physics
A collection of video lectures from a fundamentals of physics course taught at Yale University. The course is an introduction to physics and discusses Newtonian mechanics, special relativity, gravity, thermodynamics, and waves. Course...
Learn AP Physics
Learn Ap Physics: Physics B: Modern Physics
A site dedicated to help students prepare for the AP Physics B test. This specific site reviews Modern Physics including photons, photoelectric effect, atomic energy levels, The Michelson-Morley experiment, The Lorentz Transformation,...