Time Dilation, an introduction to Special Relativity.

The flow of time depends on the motion of whoever measures it. This sounds quite counterintuitive, even weird, but, it is reality: time and space are intimately linked. With the progress of science that occurred by the end of the 19nth century, the first hints of this relationship were showing up. And it’s Einstein that put it all together in 1905 with his theory of special relativity.

This video discusses time dilation, a specific effect of special relativity. The pedagogical approach here is different than from other videos you might find on Youtube, or even text books. I keep it simple, and limit myself to basic mathematics only. I believe that trying to teach Special Relativity from scratch and comprehensively in a 20minute video is nonsense. That is why I preferred to focus on time dilation as an introduction to the subject. See this video as a super teaser, and a motivator to learn more. In the conclusion of the video, I give you a direction to follow if you wish to dig further (Lorentzian transformations).

What will you learn in this video:
_ What is an inertial frame of reference (and detecting those frames which are not inertial),
_ The 2 postulates at the heart of special relativity and what these imply (basically, that’s what started the whole story),
_ What is time dilation and how to visualize it,
_ A derivation of the time dilation formula (where the most advanced maths that is used is the Pythagorean Theorem!),
_ The notion of proper time interval, that allows you to spot immediately which frame of reference has the shortest time interval between two events (very useful to solve problems),
_ Application example + exercise to check that you’ve got it, and that you can solve high school and early university time dilation questions.

Enjoy and have fun discovering this model of the Universe!

Edouard


Structure of the video:
00:00 Introduction
01:30 Content of the video
02:13 What is an inertial frame of reference?
05:10 The first postulate of special relativity
06:49 The second postulate of special relativity
08:56 Time dilation and the photon clock
10:50 Deriving the time dilation formula and the relativistic factor
13:11 The proper time interval
15:21 How to solve time dilation questions? (Special Relativity)
17:57 What we have learned of Special Relativity in this video
18:14 How to dig deeper into Special Relativity (explore Lorentzian transformations)
18:38 Conclusion


Prior knowledge required

In order to fully grasp the content of this video, not much is needed. The viewer needs to be familiar with:
_ Basic algebra
_ the fact that speed = distance / time interval


Credits :

The script, the illustrations, the music and the video were produced and presented by Edouard Reny, Ph.D. in solid state chemistry and private tutor in Physical Sciences.


Need help with your high school physics ?:

Edouard provides oneonone private tuition in Physics (face to face or by Skype). If you wish to know more about this, or contact Edouard, visit his website: https://www.physicstutor.nl/ or this one (for French speakers) : https://profdephysique.fr/.