Gamma control = how much gamma rays are emitting?

[London Geezer]

that is one wicked graph KILER....

gamma rays from TV's ... ....

someone got too much into the Hulk bandwagon.....

(imagines KILER stuck in front of a monitor with gamma correction all up, waiting till he goes all green and muscly)

 

[Ilfirin]

I'm not in a nuclear plant but I handle gamma emitting substances nearly every day. I'm not, I'm sterile, I'm not a 15' bug-eyed mutant; I pass my yearly health checks with no problems. Yes, gamma ray photons are high energy but they are also highly penetrating, so they are more likely to simply pass through human tissue than be absorbed - of course, basic statistics shows us that if you have enough of the events taking place, then no matter how unlikely an occurance is going to be, one will take place.

While I admit that I was [intentionally] overstating the medical implications of exposure to gamma radiation, they are still quite dangerous and should never be "handled" lightly. The highly penetrative ability of gamma rays makes them more dangerous, not less - that ability comes from their small wavelength (the "good" property as it makes it statistically unlikely to cause harm, but it also the reason for the two bad properties) and high magnitude of momentum/energy (3 ways of saying the same thing..). The fact that they go "straight through you" doesn't mean they do so without harm, it just means that it was never totally absorbed, which is only one of a few different ways EM radiation can interact with matter (and in the case of medium to high energy gamma radiation, one of the the least likely ways). That same property makes gamma radiation very harmful to organs and DNA, neither of which you'd want defective..

It only takes a single gamma photon hitting at the right place to cause your eventual death, that alone is enough to keep me away from them even if it's statistically unlikely. Statistics have a funny way of being wrong sometimes (put 100 pennies in a box and shake it for a while, then remove all the pennies on heads or tails and count how many you have - statistically you should have 50, though in practice that is one of the rarest numbers you get). Ironically, something that can so easily cause cancer is also used in treating cancer via shooting gamma rays at the tumor from many different angles (while being extra careful to keep them pointed away from organs and other healthy cells).

BTW, what job do you have that requires near daily direct interaction with radioactive materials?

 

[Kyyla]

Wow, you have a pretty impressive energy output in your monitor if it's really emitting gamma-rays.

 

[Neeyik]

BTW, what job do you have that requires near daily direct interaction with radioactive materials?

I'm the head of a physics department in a private school - I check the sources container daily (for the most part, this is just a cursory glance). The sources are, of course, pretty weak - they have to be in order to comply with UK education regulations. However, out of the 9 different samples I use, 5 of them are gamma emitters.

 

[London Geezer]

Wow, you have a pretty impressive energy output in your monitor if it's really emitting gamma-rays.

must be a hell of a contrast on that monitor.... like 20000000000000:1

 

[arjan de lumens]

Somewhat offtopic nit:

Statistics have a funny way of being wrong sometimes (put 100 pennies in a box and shake it for a while, then remove all the pennies on heads or tails and count how many you have - statistically you should have 50, though in practice that is one of the rarest numbers you get)

Statistically, the probability that you will get exactly 50 pennies is 7.96%, and the standard deviation of the penny count is 5. (Assuming that the coins are fair, which, IIRC, pennies are not)

 

[Ilfirin]

Statistically, the probability that you will get exactly 50 pennies is 7.96%, and the standard deviation of the penny count is 5. (Assuming that the coins are fair, which, IIRC, pennies are not)

Ah, I knew there had to be more to it. I was basically quoting what my physics teacher said after doing a [rather bad] half-life experiment with pennies. May I ask what the full proof of that statement would be (I only know the most basic statistics found in pure math courses/texts)

 

[arjan de lumens]

Statistically, the probability that you will get exactly 50 pennies is 7.96%, and the standard deviation of the penny count is 5. (Assuming that the coins are fair, which, IIRC, pennies are not)

Ah, I knew there had to be more to it. I was basically quoting what my physics teacher said after doing a [rather bad] half-life experiment with pennies. May I ask what the full proof of that statement would be (I only know the most basic statistics found in pure math courses/texts)

For the 7.96% number: number the pennies from 1 to 100. The total number of heads/tails combinations is then easily seen to be 2^100 = about 1.268e30, all of which are equally likely. The number of heads/tails combinations with exactly 50 heads is a bit harder to explain the reasoning behind, but the resulting number, if you are familiar with the factorial function, is given by 100!/(50!*50!) = about 1.009e29.

The probability that you get one of 1.009e29 combinations from a set of 1.268e30 combinations is then given by 1.009e29/1.268e30 = 7.96%. The standard deviation is also a bit hard to explain - I just cheated out and computed it from formulas found here (standard deviation is given by the square root of the quantity called "variance", which in turn is the average of the square of the deviation of data from the mean value).

Statistics as a subject takes some effort to study and truly understand and does contain a number of terms that aren't commonly encountered otherwise - it's all too common to hear people who haven't seriously studied it deride it as bullshit or derive nonsense results. Which is not to say that statistics doesn't have limitations; it does, especially when it comes to bias in input data or nonlinear correlations.

 

[Ilfirin]

Hmm. Your post inspired me to do some searching and I found an elementary statistics textbook in the house (whose it is, I don't know) to get me started. About 1/10th of the way through now.

 

[K.I.L.E.R]

Thanks guys.

I have a lot more to learn.

 

[Simon F]

I have a lot more to learn.

A maxim everyone should take to heart

 

[davefb]

yeah, but maybe everthing has been learnt
"The more important fundamental laws and facts of physical science have all been discovered, and these are now so firmly established that the possibility of their ever being supplemented in consequence of new discoveries is exceedingly remote. -Albert Michelson, 1903 "

mind you i was googling for that quote and found a similar one by maxwell 30 years early ( the irony!) . theres some classics here , babbage , (predicting gigo?) .

"On two occasions I have been asked [by members of Parliament], 'Pray, Mr. Babbage, if you put into the machine wrong figures, will the right answers come out?' I am not able rightly to apprehend the kind of confusion of ideas that could provoke such a question. -Charles Babbage "

link
http://www.physics.montana.edu/students/thiel/quotes.html

-dave-

 

[Ilfirin]

"The more important fundamental laws and facts of physical science have all been discovered, and these are now so firmly established that the possibility of their ever being supplemented in consequence of new discoveries is exceedingly remote." -Albert Michelson, 1903

Oh, that poor chap. He said that 3 years after the first 'spark' that inevitably lead to disproving everything he knew to be true, 2 years before that patent office worker explained the photoelectric effect (with the explanation a direct slap in the face of the accepted theories of the time) and created the special theory of relativity.. at the beginning of the very century that ended up re-writing all those fundamental laws he thought to be the end all be all. That quote's even worse than IBM's "I think there is a world market for maybe five computers" -Thomas Watson (chairman of IBM, 1943). At least he (Michelson) wasn't alone, that's the attitude everyone had at that time.

Just goes to show you that if you ever think you know everything there is to know about something (whether it be a single subject, or everything) it's only because you are so horribly ignorant to everything.

 

[London Geezer]

"Knowing everything there is to know" is an absolutely ridiculous statement. Utterly and totally riduculous. I can't even begin to imagine what would take to know everything there is to know, especially regarding physics. And i can't even begin to imagine how twisted are the minds of people who actually think that.

 

[Ilfirin]

Aye. It's even a physical impossibility with the uncertainty principle!

Understanding is far more important anyway.