About This Paper
There are two theories of Relativity.
One is Special Relativity and the other is General Relativity.
Our focus in this article will be on Special Relativity.
Some basic concepts from high school physics are needed. But they are only concepts, literally.
Sections 1 & 2 are based around the concepts of relative motion and average speed.
Sections 3 to 6 uses Newton's second law of motion and the property of wave.
The last section, "About Mass", requires a little bit knowledge in Calculus.