Physics for Smarties: Time Dilation

This is a brief description of the concept of time dilation in the theory of Special Relativity, including the math behind it!

It's my first ever video, feedback is very much appreciated!

Category:

Science & Technology

Tags:

• physics
• time
• dilation
• science
• special
• relativity
• for
• dummies
• einstein

[Nidhogg05]

PS: the music in the middle was a bit of a practical joke. I do hope that the formula on the screen at that time gave you more of a shock than the music ;)

[Nidhogg05]

final

As for the light-clock, this is a thought-experiment, the predictions it makes (the formula) have been verified and form the basis of our current understanding of the physical world. It's called ''special'' because it only talks about a special circumstance (no gravity, just light). It's a thought experiment that is at the beginning of the relativity theory, the one that changed our perspective forever. It's the early incarnation of the idea, not the finished product.

[Nidhogg05]

The argument that ''this doesn't work with a mechanical clock'' is irrelevant, because special relativity doesn't describe such an occurance. SRT only deals with light, and not with gravity. A mechanical clock does undergoe time dilation, but this can only be explained by the bending of space-time due to gravity, in general relativity.

PS: the mechanical clock does suffer time-dilation, just like anything else. To say that it doesn't breaks every aspect of relativity.

[Nidhogg05]

To react to a few common questions: 1

The triangle in the moving clock is caused by the observer standing still, while the clock is moving past you at speed (v). To an observer in the train, point A and C are at the same location, to the person on the ground, they are apart. It's not about the angle, but about the the fact that to the observer the distance by the light traveled in the same time seems bigger (because of the forward speed) than to the observer in the train. the dilation effect.

[Cyberdactyl]

your video completely trashes itself when you crank the volume of the head banger music. It was all I could do to drop the web page before everyone in the room was screaming.

[Nidhogg05]

@Cyberdactyl it was a bit of practical joke from my side ;)

[Nidhogg05]

@MrMillsms

You need to differentiate between special and general relativity. Special relativity (as explained in this vid) uses no more than logic and high school math. The calculation in the vid is the same one you'll be taught in a physics course. The math behind special relativity is so easy that it makes an excellent subject for a youtube video, because you don't need a PhD to understand it. In short, special can be outlined in a youtube vid, general requires 5 years of studying ;)

[MrMillsms]

always find it humorous when people explain relativity or quantum mechanics on the youtube comment section.

The truth is that the mathematics and physics involved in these are staggering beyond belief and that the person explaining it is usually regurgitating a layman's explanation they saw on TV.

Even with a Ph.D in quantum optics and mechanics, one has trouble making sense of the material -- let alone explaining it.

At least I find this to be the case in my life

[WhosYourDaddy82]

I've read about this thought experiment. It assumes that the observer outside the train can "see" the light pulse. They can't because it never entered their eyes or instruments. This thought experiment is pure madness.

[bridgetroll9]

Prove time exists as a physical part of the universe before you say it exists. Only insane people believe it is possible to get something from nothing.

Matter, Gravity, Energy, Motion, Heat, Cold,

Light, Electricity, Radiation, Magnetic Fields, Sound, Wind etc all have to come from something somewhere.

They all come from the same place from the same thing. The place and thing is the so called "nothing" or "empty space".

[MiskenTheCat]

At what speed would the spacecraft be traveling according to the observer? If the answer is C, would the observer see the spacecraft and light traveling at the same speed?

[schr4nz]

@cybervoid it's aphex twin, aphex twin is possibly the best (or at least most influential) electronic musician of our time.

[schr4nz]

I started watching this and thought my winamp or some background youtube video started playing Aphex Twin, so before I continue watching your video, I commend you on your musical taste, Sir.

[cybervoid]

@Nidhogg05 Yeah, the porn music needs to go. I just can't watch this.

Nothing personal.

[420dankykush]

@alcolyte76 you ignorant twit thats what you are sir i am standing by it along with facts and logical ppl, not standing alone like those who cant accept transcedental truths like evolution and time dilation, who are you and who do you think you are for confusing these users with your nonsense? stop throwing everybody off, stop advertising your science-run-a-muck, you take some good education and you taint it with your misconception, its so sad