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2 minutes ago, John Cuthber said:

That's a requirement for a perfect mirror.

But the impact of a photon on one side of the box pulls the rest of the box along  by stretching it out a bit.

Unless that's perfectly elastic too, there's a loss of energy.

Yes, you're right, even under "perfect conditions" the energy loss is present. Thanks for your time and replies

On 22/10/2017 at 7:07 AM, vovka said:

Hi dude!

I was concerned with the same questions and just surfed the internet...I picked up some books and started working through. The main question is what is the best choice for self  studying, and the answer varies from person to person depends on his background and goals. Certainly you should have a calculus book (there are plenty of them in net),  some general physics book (like 'fundamentals of physics' by Halliday and Resnick) and probably linear algebra book. If your knowledge in elementary algebra and in trigonometry is not strong enough you should look for some as well. If you want I can give you some pdf-copies I use or the reference to the source I got them...

Good luck with your studying.

Many thanks for your support, and yes, I start to search books that cover my requeriments and point to my objectives. When I find good sources I will post here if anyone is interested in it... Thanks again

On 30/10/2017 at 5:05 PM, John Cuthber said:

I can try.

If you drop a tennis ball it bounces, but not as high as you dropped it from. Energy is lost as heat.

Other balls bounce better or worse, but none gets back to the height it started from.
In the same way, when you make a box out of mirrors and set a photon bouncing round in it you will lose energy because the box gets stretched (very slightly) when a  photon hits it.

Now I understand... But, if the shock beteween the mirror and the photon would  a 100% elastic shock?

On 30/10/2017 at 4:55 PM, swansont said:

Perfect mirrors do not exist in reality. You can use them to analyze the ideal case, which is often done in thought experiments. But your wording in the OP implied you wanted a real-world analysis.

Maybe the "perfect mirrors" will be discovered in a future, but for the moment it's only a ideal case as you write. Thanks for your answer

On 28/10/2017 at 5:37 PM, Strange said:

It will be absorbed by the mirrors because they are not perfect reflectors.

If you could create a perfect reflector then, yes, the light would stay in there forever bouncing around. But that is not possible.

On 29/10/2017 at 9:00 AM, swansont said:

One of the reasons 100% reflection is not possible is that momentum must be conserved. When the photon turns around, there must be some recoil by the mirror, so some energy must be transferred.

On 29/10/2017 at 9:03 AM, Strange said:

That occurred me afterwards, as well. Does that mean that with ideal mirrors, the light would get progressively red shifted?

On 29/10/2017 at 0:17 PM, dimreepr said:

wouldn't that mean that any angle other than 180 would eventually see a loss of energy with respect to the box?

22 hours ago, swansont said:

I think an ideal mirror would have to be infinitely massive. Any real mirror would have this tiny redshift.

Only if you have an infinitely rigid box, another impossible ideal. 

I have readed your answers and reached to the conclusion that is impossible a perfect boucing without loss energy even with "perfect mirrors", because the same bouncing means a enegy transfer beteween the photon and the wall. I'm wrong?

22 hours ago, swansont said:

I think an ideal mirror would have to be infinitely massive. Any real mirror would have this tiny redshift.

Only if you have an infinitely rigid box, another impossible ideal. 

22 hours ago, John Cuthber said:

I think it needs to be perfectly elastic, rather than perfectly rigid. So it's impossible for a different reason.

 

The punch-line to all this discussion of why it's impossible is ...

people actually do it.

https://en.wikipedia.org/wiki/Cavity_ring-down_spectroscopy

http://www.chem.ualberta.ca/~xu/research/crds.htm

The mirrors rigidness can influence in the energy conservation? Can you explain it better.

13 hours ago, Endy0816 said:

Would traveling infinite distance be the equivalent? Keep thinking frequency should change regardless. Not sure on math though.

I think not, because traveling an infinite distance will make them to conserve it momentum and energy as far they encounter a obstacle.

So, we can assume that if the mirror have 100% reflection it will be possible? And I am not reffering to a single photon, I reffer to waves of light bouncing against the walls, as I write "...turn on a light for 5 seconds..."

Hello people, as the title says, I want to know if light can be closed in a mirror's box. My idea is, build a sealed mirror's box (The mirrors must reflect the 100% of the light), in that any light particle can escape, later turn on a light inside for 5 seconds and then turn it off (Let's suppose that the light source is "invisible" to make that the light can't be abosrbed for anything). So if I do that... Will the light be closed forever, bouncing against the walls? Or it will gradually start losing momentum and/or luminescence?

20 hours ago, Roamer said:

As stated, it will differ per poison, (but also per person) some poisons you will never get used to,

others, like alcohol, can be rather immunized to by the individual but you can't get a meaningfull discussion going since halve the participants are drunk

And NO, you cannot reach 100% immunity against most poisons, mainly because too much of something will always be too much;

people have died from drinking TOO MUCH (8+ liters) of water for example.

Yeah, the effects and the time to get certain inmunity will differ per person. And the inmunity to the alcohol would be good, but I don't drink alcohol so it's useless for me . So, as too much from something is bad... No 100% inmunity.

19 hours ago, John Cuthber said:

I think that's one of the dumbest ideas I have heard in ages.

The human world is full with bad ideas, one more will not make it worse.

19 hours ago, Endy0816 said:

Joking reference to the Princess Bride where this method is used. 

Seriously though don't recommend testing. In real life you are more likely to just end up dead.

18 hours ago, StringJunky said:

A bit like playing Russian Roulette with yourself and counting how many times you can get away with it before you find the bullet.

Ah, that was... Sorry, I don't watch TV or movies. And yes, I'm not going to test it in real life, it's dangerous, but thanks for the advice.

4 hours ago, DrP said:

Yea, sorry it was on the TV and it was some time back (10 years at least). I done a quick search for a youtube clip or something but found nothing on the guy. He was based in the desert and was special forces...  big guy with a good constitution. I think his size and fitness helped him pull through his first couple of bites (which were accidental) then he started to administer the poison himself to build immunity over years. If I spot it again or get more time to look it up further then I will let you know.

I hope that I can found it, I'm a little surprised for the guy resistance to support two bites. Thanks for serach it and give me the description, and thanks in advanced if you can found it. 

On 17/10/2017 at 2:22 AM, CharonY said:

I sincerely hope that he did not try to figure it out experimentally.

Don't worry, I will not try... For now

On 16/10/2017 at 4:37 PM, John Cuthber said:

It will work for some things, but not others.

Here's the interesting question: how do you know if it worked?

22 hours ago, John Cuthber said:

How else?

Well... I think a way to experiment it's, after to reach inmunity to the lethal dose, stop the "treament" for a month, later inyect me the approximately the 85% of the lethal dose and evaluate the effects. What do you think? Anyone have others ideas?

On 17/10/2017 at 6:22 AM, DrP said:

I saw a documentary once where an army special forces guy who had been in the desert for a long time had built up a resilience to scorpion stings. I think it started by accident where he was stung, and then over the years he just allowed himself to be stung every day or so. Now he can take a hit from a scorpion that would normally kill someone and he just gets a slight headache.

Sounds interesting. Can you provide me a link to the documental? Or you saw it in Discovery Channel, Animal Planet or some channel like that?

On 17/10/2017 at 5:22 AM, Endy0816 said:

If you start with Iocane powder the rest are easy.

Can you be more especific, please?

Hello people, as the title says, I want to know if it's possible to develop inmunity agains posions (Like spider and snake venom's) and toxins (Like botulinum) through inyecting little no lethal dose and increasing it over time. I have readed about the mithridatism, but I want to know if this practice really works and if it were so. It will work with all poisons type, like cyanire? And, the inmuty can reach to 100% (For example: If a inland taipan bites me, I survive without consuming any antidote)?

Hello people, this is my first topic so forgive me if I commit any mistake, cleared up that, I want to know what books, preferably of course with exercises, do you recommend to me to as the title says, learn match, physic and algebra from scratch. I like to be autodidact so I will learn and practice solo, but that doesn't mean that I don't will gonna aks for help.

I'm actully studying systems engineering, and my knowledge in math arrives until to operate and derivate with functions, in physic until to UVRM (Uniformly Varied Rectilinear Motion), and in algebra until to vectors. But although I have certain know in the subjects, I want to learn them from scratch with books.

One fact that's maybe important, is that some day I want to learn quatum physic, but I will do it in a future because it interests me.

I hope you can help and recommend me, and sorry if I wrote too much. Many thanks in advance.