5 ms·

I once tried to make Geiger counter from webcam. I covered the lid with dark paper. I put it in front of a banana and then I read frames from it and counted noi

by dvh 10y ago

I once tried to make Geiger counter from webcam. I covered the lid with dark paper. I put it in front of a banana and then I read frames from it and counted noise spikes. Didn't work.

devnonymous 10y ago
Was the banana radioactive ? If it wasn't I imgaine it did work.
- bbrazil 10y ago
  Bananas are the 2nd most radioactive food, due to their Potassium content. Brazil nuts are the most radioactive. https://en.wikipedia.org/wiki/Banana_equivalent_dose https://en.wikipedia.org/wiki/Banana_equivalent_dose
  - deleted 10y ago
    [deleted]
  - adsfqwop 10y ago
    Btw. just for curiosity, there is a difference in the source of radiation as it pertains to how dangerous it is. Banana (potassium) radiation is mostly harmless to humans. Nuclear weapon or reactor radiation (for example caesium) is not. The Banana equivalent dose is therefore a bit of a misleading term, and I have sometimes seen it used to dismiss other more harmful radiation sources as harmless, because of this incorrect banana comparison. http://www.washingtonsblog.com/2013/04/fake-science-alert-fukushima-radiation-cant-be-compared-to-bananas-or-x-rays.html http://www.washingtonsblog.com/2013/04/fake-science-alert-fu... Here is an example of using the banana comparison in an incorrect manner: http://www.forbes.com/sites/timworstall/2013/08/10/the-fukushima-radiation-leak-is-equal-to-76-million-bananas/#1a9262b4c1e6 http://www.forbes.com/sites/timworstall/2013/08/10/the-fukus...
    - gh02t 10y ago
      To clarify, the gamma energy from K-40 in bananas is around 1.5 MeV, which is dangerous to humans. It's not the most dangerous, but it is dangerous in significant amounts (which are much much higher than what is in a banana). A BED is usually taken as 1 micro-Sievert. Sieverts are a unit for measuring the biological effect of radiation, hence they are normalized to adjust for how harmful the given type of radiation is. A dose of 1 Sievert represents a 5.5% chance of eventually developing cancer. 1 Sievert is 10000000 BEDs. The part that is a bit misleading about the BED is that it's not the same as the dose you get from eating a banana. This is because of how potassium is absorbed in the body; all the K-40 in the banana isn't staying around in your body. The BED is the dose you would be exposed to for absorbing the equivalent amount of K-40 in the same number of bananas. Bananas are fine for putting small doses or activities into perspective since the biological effects are negligible, but are not really great for comparing against more significant doses.
    - Merad 10y ago
      It isn't so much the source of the radiation, as it is what your body does with the material. When you eat a banana, your body gains additional potassium, and over the next several days your kidneys will expel that excess. So, your exposure to the tiny amount of Potassium-40 in the banana is very brief. OTOH, your body treats the Strontium-90 in nuclear fallout like calcium, depositing it in your bones and bone marrow subjecting you to continuous radiation exposure. Likewise Iodine-131 will concentrate in the thyroid.
      - mungoman2 10y ago
        What about then if you eat a banana daily, so there is no chance of fully expelling the potassium
        Merad 10y ago
        Bear in mind that your body always contains potassium (mostly non-radioactive, but a tiny bit is radioactive). Eating a banana just slightly increases your exposure for a short time. If we take a look at our handy dandy xkcd radiation chart[1], we can see that eating a banana every day for a year exposes you to about 36.5 uSv radiation, slightly less than you get during a six hour airline flight. By comparison, the potassium naturally contained in your body already exposes you to 390 uSv radiation in a year. [1]: http://xkcd.com/radiation/ http://xkcd.com/radiation/
  - skykooler 10y ago
    Kidney beans have far more potassium (1406 mg per 100g) than bananas (358 mg per 100g). Potatoes (421 mg), sunflower seeds (645 mg), kale (421 mg) and spinach (558 mg) all also have more potassium than bananas. Bananas are not that high in potassium relative to all other foods; they are merely high relative to other fruits. (But even in fruits, avocados and figs both have more potassium than bananas.) As the Wikipedia article on Bananas[1] states: "Although bananas are commonly thought to supply exceptional potassium content,[86] their actual potassium content is relatively low per typical food serving at only 8% of the Daily Value (right table). A compilation of potassium content in common foods consumed in the United States shows that raw bananas rank 1,611th, supplying 358 mg of potassium per 100 g". [1] https://en.wikipedia.org/wiki/Banana https://en.wikipedia.org/wiki/Banana
tonetheman 10y ago
Actually that sounds like a fun project.
tonetheman 10y ago
Actually that sounds like a fun project.
1ris 10y ago
I tried this with a radioactive probe. It didn't work aswell.
prashnts 10y ago
Should have tried cooling it. :) http://petapixel.com/2016/10/11/cooled-nikon-d5500a-chills-sensor-clearer-star-photos http://petapixel.com/2016/10/11/cooled-nikon-d5500a-chills-s...
irremediable 10y ago
This is really cool! I found a couple of projects online (e.g. http://www.randombio.com/webcam.html http://www.randombio.com/webcam.html) where people tested out their webcam counter by using a smoke detector as an alpha source, and had some success.
Retr0spectrum 10y ago
It's definitely possible to use a phone camera [0]. I know someone who has a few radiation samples and it worked very well. [0]: https://play.google.com/store/apps/details?id=com.rdklein.radioactivity&hl=en_GB https://play.google.com/store/apps/details?id=com.rdklein.ra...
new299 10y ago
Pedantry: It wasn't a geiger counter because it wasn't using a Geiger-Müller tube. I don't think you'd see much of a difference even with a decent Geiger counter from a banana. The levels of radiation in food are tiny, and building equipment to measure it is not easy. Probably if you found decent radiation source, or perhaps took it up in an airplane you'd see a difference.
- mef51 10y ago
  if you're a little crazy you can take the radioactive americium out of a smoke detector and use that as a source
  - pbhjpbhj 10y ago
    And if you're a lot crazy you can build a fission reactor... our maybe that was a different source isotope?
    - monocasa 10y ago
      If you're not that crazy, you can build a fusion reactor, although the design necessarily requires more energy than it puts out. Teens have built these for science fair projects. https://en.wikipedia.org/wiki/Fusor https://en.wikipedia.org/wiki/Fusor
- CamperBob2 10y ago
  For what it's worth, I've used a (real) Geiger counter to examine not only a banana, but potassium supplement pills. I wasn't able to detect even the slightest increase over background radiation from either.
theophrastus 10y ago
Unless i'm getting my natural sources mixed up, a banana is slightly radioactive due to Potassium-40 and that decays beta. A standard Geiger counter easily detects x-ray/gamma/photons, where beta decay is via an ejected electron and its detection requires a specially thin 'window'. (Which often occurs as a 'lollipop'[1] detector as opposed to a cylinder. huh, they refer to it as a 'pancake' detector) Fun fact: there are many lab benches with painted splotches on them. Beta source spills being able to be shielded by even a coat of paint. 1. https://en.wikipedia.org/wiki/Geiger_counter#/media/File:Geiger_counter_2.jpg https://en.wikipedia.org/wiki/Geiger_counter#/media/File:Gei...

by dvh 10y ago

I once tried to make Geiger counter from webcam. I covered the lid with dark paper. I put it in front of a banana and then I read frames from it and counted noise spikes. Didn't work.

devnonymous 10y ago

Was the banana radioactive ? If it wasn't I imgaine it did work.

bbrazil 10y ago
Bananas are the 2nd most radioactive food, due to their Potassium content. Brazil nuts are the most radioactive. https://en.wikipedia.org/wiki/Banana_equivalent_dose https://en.wikipedia.org/wiki/Banana_equivalent_dose
- deleted 10y ago
  [deleted]
- adsfqwop 10y ago
  Btw. just for curiosity, there is a difference in the source of radiation as it pertains to how dangerous it is. Banana (potassium) radiation is mostly harmless to humans. Nuclear weapon or reactor radiation (for example caesium) is not. The Banana equivalent dose is therefore a bit of a misleading term, and I have sometimes seen it used to dismiss other more harmful radiation sources as harmless, because of this incorrect banana comparison. http://www.washingtonsblog.com/2013/04/fake-science-alert-fukushima-radiation-cant-be-compared-to-bananas-or-x-rays.html http://www.washingtonsblog.com/2013/04/fake-science-alert-fu... Here is an example of using the banana comparison in an incorrect manner: http://www.forbes.com/sites/timworstall/2013/08/10/the-fukushima-radiation-leak-is-equal-to-76-million-bananas/#1a9262b4c1e6 http://www.forbes.com/sites/timworstall/2013/08/10/the-fukus...
  - gh02t 10y ago
    To clarify, the gamma energy from K-40 in bananas is around 1.5 MeV, which is dangerous to humans. It's not the most dangerous, but it is dangerous in significant amounts (which are much much higher than what is in a banana). A BED is usually taken as 1 micro-Sievert. Sieverts are a unit for measuring the biological effect of radiation, hence they are normalized to adjust for how harmful the given type of radiation is. A dose of 1 Sievert represents a 5.5% chance of eventually developing cancer. 1 Sievert is 10000000 BEDs. The part that is a bit misleading about the BED is that it's not the same as the dose you get from eating a banana. This is because of how potassium is absorbed in the body; all the K-40 in the banana isn't staying around in your body. The BED is the dose you would be exposed to for absorbing the equivalent amount of K-40 in the same number of bananas. Bananas are fine for putting small doses or activities into perspective since the biological effects are negligible, but are not really great for comparing against more significant doses.
  - Merad 10y ago
    It isn't so much the source of the radiation, as it is what your body does with the material. When you eat a banana, your body gains additional potassium, and over the next several days your kidneys will expel that excess. So, your exposure to the tiny amount of Potassium-40 in the banana is very brief. OTOH, your body treats the Strontium-90 in nuclear fallout like calcium, depositing it in your bones and bone marrow subjecting you to continuous radiation exposure. Likewise Iodine-131 will concentrate in the thyroid.
    - mungoman2 10y ago
      What about then if you eat a banana daily, so there is no chance of fully expelling the potassium
      - Merad 10y ago
        Bear in mind that your body always contains potassium (mostly non-radioactive, but a tiny bit is radioactive). Eating a banana just slightly increases your exposure for a short time. If we take a look at our handy dandy xkcd radiation chart[1], we can see that eating a banana every day for a year exposes you to about 36.5 uSv radiation, slightly less than you get during a six hour airline flight. By comparison, the potassium naturally contained in your body already exposes you to 390 uSv radiation in a year. [1]: http://xkcd.com/radiation/ http://xkcd.com/radiation/
- skykooler 10y ago
  Kidney beans have far more potassium (1406 mg per 100g) than bananas (358 mg per 100g). Potatoes (421 mg), sunflower seeds (645 mg), kale (421 mg) and spinach (558 mg) all also have more potassium than bananas. Bananas are not that high in potassium relative to all other foods; they are merely high relative to other fruits. (But even in fruits, avocados and figs both have more potassium than bananas.) As the Wikipedia article on Bananas[1] states: "Although bananas are commonly thought to supply exceptional potassium content,[86] their actual potassium content is relatively low per typical food serving at only 8% of the Daily Value (right table). A compilation of potassium content in common foods consumed in the United States shows that raw bananas rank 1,611th, supplying 358 mg of potassium per 100 g". [1] https://en.wikipedia.org/wiki/Banana https://en.wikipedia.org/wiki/Banana

tonetheman 10y ago

Actually that sounds like a fun project.

tonetheman 10y ago

Actually that sounds like a fun project.

1ris 10y ago

I tried this with a radioactive probe. It didn't work aswell.

prashnts 10y ago

Should have tried cooling it. :) http://petapixel.com/2016/10/11/cooled-nikon-d5500a-chills-sensor-clearer-star-photos http://petapixel.com/2016/10/11/cooled-nikon-d5500a-chills-s...

irremediable 10y ago

This is really cool! I found a couple of projects online (e.g. http://www.randombio.com/webcam.html http://www.randombio.com/webcam.html) where people tested out their webcam counter by using a smoke detector as an alpha source, and had some success.

Retr0spectrum 10y ago

It's definitely possible to use a phone camera [0]. I know someone who has a few radiation samples and it worked very well. [0]: https://play.google.com/store/apps/details?id=com.rdklein.radioactivity&hl=en_GB https://play.google.com/store/apps/details?id=com.rdklein.ra...

new299 10y ago

Pedantry: It wasn't a geiger counter because it wasn't using a Geiger-Müller tube. I don't think you'd see much of a difference even with a decent Geiger counter from a banana. The levels of radiation in food are tiny, and building equipment to measure it is not easy. Probably if you found decent radiation source, or perhaps took it up in an airplane you'd see a difference.

mef51 10y ago
if you're a little crazy you can take the radioactive americium out of a smoke detector and use that as a source
- pbhjpbhj 10y ago
  And if you're a lot crazy you can build a fission reactor... our maybe that was a different source isotope?
  - monocasa 10y ago
    If you're not that crazy, you can build a fusion reactor, although the design necessarily requires more energy than it puts out. Teens have built these for science fair projects. https://en.wikipedia.org/wiki/Fusor https://en.wikipedia.org/wiki/Fusor
CamperBob2 10y ago
For what it's worth, I've used a (real) Geiger counter to examine not only a banana, but potassium supplement pills. I wasn't able to detect even the slightest increase over background radiation from either.

theophrastus 10y ago

Unless i'm getting my natural sources mixed up, a banana is slightly radioactive due to Potassium-40 and that decays beta. A standard Geiger counter easily detects x-ray/gamma/photons, where beta decay is via an ejected electron and its detection requires a specially thin 'window'. (Which often occurs as a 'lollipop'[1] detector as opposed to a cylinder. huh, they refer to it as a 'pancake' detector) Fun fact: there are many lab benches with painted splotches on them. Beta source spills being able to be shielded by even a coat of paint. 1. https://en.wikipedia.org/wiki/Geiger_counter#/media/File:Geiger_counter_2.jpg https://en.wikipedia.org/wiki/Geiger_counter#/media/File:Gei...