General science thread

July 1st, 2017 at 4:32:24 AM permalink
odiousgambit
Member since: Oct 28, 2012
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Trivia Question: how much more "background radiation" from space and the Earth does one receive in Denver as compared to, say, Baltimore?

*twice as much?
*3 times as much?
*4 times as much?
*5 times as much?
*after a week you glow in the dark

No fair looking it up

I have another trivia question later and will reveal this answer then.
Mustard:You like Kipling, Miss Scarlet? Sure, I'll eat anything [from movie]
July 3rd, 2017 at 3:26:48 AM permalink
odiousgambit
Member since: Oct 28, 2012
Threads: 89
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Quote: odiousgambit
Trivia Question: how much more "background radiation" from space and the Earth does one receive in Denver as compared to, say, Baltimore?


4 times as much in Denver
I'll reveal my source later, it's connected to the next trivia Q:

Why is there radioactive material in the typical home smoke detector?
Mustard:You like Kipling, Miss Scarlet? Sure, I'll eat anything [from movie]
July 3rd, 2017 at 4:37:42 AM permalink
Pacomartin
Member since: Oct 24, 2012
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Quote: odiousgambit
Trivia Question: how much more "background radiation" from space and the Earth does one receive in Denver as compared to, say, Baltimore?


This source seems to disagree radically with your answer.


http://news.mit.edu/1994/safe-0105

Sources of Naturally Occurring Radiation (Whole Body Equivalents)
300 millirems-Average annual natural background radiation, sea level (includes your own body radiation, cosmic radiation and radon).
400 millirems-The city of Denver's average annual natural background radiation (altitude 5,000 feet).
July 3rd, 2017 at 5:21:24 AM permalink
rxwine
Member since: Oct 24, 2012
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Quote: odiousgambit
Why is there radioactive material in the typical home smoke detector?


To make "dirty" bombs is probably not it.
No one has ever proven I am not God.
July 3rd, 2017 at 6:40:54 AM permalink
Face
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Quote: odiousgambit
4 times as much in Denver
I'll reveal my source later, it's connected to the next trivia Q:

Why is there radioactive material in the typical home smoke detector?


The particulates in smoke block the radiation from reaching the sensor. Similar to any laser type things in, say, agarage door openers, the blocking results in an activation of the device.
Be bold and risk defeat, or be cautious and encourage it.
July 3rd, 2017 at 8:54:41 AM permalink
odiousgambit
Member since: Oct 28, 2012
Threads: 89
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Quote: Pacomartin
This source seems to disagree radically with your answer.


either it's a disagreement or it's a math mistake of mine, I made a deduction from something else

frankly a 4X factor did surprise me

Quote: rxwine
To make "dirty" bombs is probably not it.


But you could, I guess, make one dirty enough to at least be a sensation if not a danger. Are we giving terrorists ideas?

Face: your answer is close, you have the right idea, but the full answer is slightly different

Maybe since there is a dispute on the first one I should go ahead and give that source
Mustard:You like Kipling, Miss Scarlet? Sure, I'll eat anything [from movie]
July 3rd, 2017 at 9:07:16 AM permalink
odiousgambit
Member since: Oct 28, 2012
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the claim that got me to indicate 4X, which I too am doubting now, is from the statement in the link that a year's worth of radiation from a home's smoke detectors was equal to a few hours of background radiation. "An East Coast resident receives that dose in about 12 hours, a Denver resident in three." I didn't think such a source might get it wrong [or did it?]............ https://www.nrc.gov/reading-rm/doc-collections/fact-sheets/smoke-detectors.html
Mustard:You like Kipling, Miss Scarlet? Sure, I'll eat anything [from movie]
July 3rd, 2017 at 1:07:28 PM permalink
Face
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Quote: odiousgambit

Face: your answer is close, you have the right idea, but the full answer is slightly different


What do you expect from a work poop, a dissertation? XD
Be bold and risk defeat, or be cautious and encourage it.
July 4th, 2017 at 4:31:23 AM permalink
rxwine
Member since: Oct 24, 2012
Threads: 127
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Quote:
A bunch of half-sunken structures off the Italian coast might sound less impressive than a gladiatorial colosseum. But underwater, the marvel is in the material. The harbor concrete, a mixture of volcanic ash and quicklime, has withstood the sea for two millennia and counting. What's more, it is stronger than when it was first mixed.

The Roman stuff is “an extraordinarily rich material in terms of scientific possibility,” said Philip Brune, a research scientist at DuPont Pioneer who has studied the engineering properties of Roman monuments. “It's the most durable building material in human history, and I say that as an engineer not prone to hyperbole.”


Quote:
In this instance, the key ingredient proved to be seawater. As seawater percolated within the tiny cracks in the Roman concrete, Jackson said, it reacted with the phillipsite naturally found in the volcanic rock and created the tobermorite crystals.

“Aluminous tobermorite is very difficult to produce,” she said, and requires very high temperatures to synthesize small amounts. Cribbing from the ancient Romans might lead to better production of tobermorite, which is prized for its industrial applications, she noted.


https://www.washingtonpost.com/news/speaking-of-science/wp/2017/07/04/ancient-romans-made-worlds-most-durable-concrete-we-might-use-it-to-stop-rising-seas/?utm_term=.2fa55c868e7e
No one has ever proven I am not God.
July 4th, 2017 at 12:20:29 PM permalink
odiousgambit
Member since: Oct 28, 2012
Threads: 89
Posts: 2205
So a smoke detector uses radioactive material because the air around such material becomes ionized, and an electric current can be passed through ionized air. Smoke interferes and cuts the current, setting off the alarm.

The impulse to make this a trivia question led eventually to my embarrassing deduction that background radiation is dramatically higher in higher elevations, so I have wasted some more time* trying to figure out why the NRC website led me astray by apparently claiming the same thing.

I think I have figured it out. The NRC web-page cited was evidently comparing only alpha particle emission, and smoke detectors generally use alpha-particle emitters. Of background radiation, the component that comes from cosmic rays contains a lot of alpha particles:

Quote: first link
Of primary cosmic rays, which originate outside of Earth's atmosphere, about 99% are the nuclei (stripped of their electron shells) of well-known atoms, and about 1% are solitary electrons ... 9% are alpha particles, identical to helium nuclei


Which leads to a different claim on a Wikipedia page:

Quote: second link
For example, the city of Denver in the United States (at 1650 meters elevation) receives a cosmic ray dose roughly twice that of a location at sea level.


So we are being led into an "apples and oranges" comparison. While citing background radiation the actual comparison is evidently only for alpha particle radiation, which has to be a small component of Earth-generated background since air alone quickly absorbs alpha particles. Whether or not the article correctly suggest a 4X difference seems to be debatable as well, as it would seem 2X is as extreme as you can conjure. edit: maybe not, it is a bit complicated. Ironically, the matter of Denver vs sea-level hardly needed to mentioned at all if you ask me.



https://en.wikipedia.org/wiki/Cosmic_ray

https://en.wikipedia.org/wiki/Background_radiation

You might wonder if alpha particle radiation is nearly harmless no matter what, since it is basically just stripped helium. But such radiation is ejected with energy [high velocity] and it can damage DNA and I guess cells generally:

Quote: link below
The Russian dissident Alexander Litvinenko's 2006 murder by radiation poisoning is thought to have been carried out with polonium-210, an alpha emitter.


https://en.wikipedia.org/wiki/Alpha_decay

*Except that it has been interesting, hopefully to everyone reading this
Mustard:You like Kipling, Miss Scarlet? Sure, I'll eat anything [from movie]