No Such Thing as a Radioactive Potato or Banana

[antiprotons]

The biggest problem here is that your meter isn't going to detect the radiation from potassium decay very effectivly. If you used a large pancake probe with lots of time and a bag of potatos or bananas, perhaps. Using a scintillation counter, you can detect gammas from K40 much better. Really, the problem is that you are using the wrong instrument, not that there isn't radiation.

Lack of detection means little. You cannot detect neutrons, yet they are still there.

[rich1051414]

lol dude. Potatoes and Bananas are radioactive, as they contain potassium. However this is a normal safe and healthy level of radiation, and you will not get cancer from it. You will get illnesses(hypokalemia) from NOT ingesting the radioactive potassium however. Maybe that will help clear the air.

[lollazers]

As other posters said, EVERYTHING is radioactive. Even you. If you can't detect a banana above background with a 1 min+ integration count, that just means you have a detector with low gamma sensitivity. Also the PM1703 won't detect K40 because the PM1703 is lazy and Ignores low activity sources. K40 emits gammas not betas.

[sidewaysfcs0718]

what is the point of this stupid video??

almost everything is radioactive

there is in fact no place on earth, or the entire universe for that matter, where u can not be iradiated ....

bananas are just commonly given as an example cus most people dont like the idea of them being radioactive ...

[antiprotons]

Potatos and banannas are radioactive, given their K40 content, but the levels are extreemly tiny and totally safe. You would need a scentillator crystal to really see anything in them. They are radioactive, but not much. They emit beta negative, positive, and beta capture. Extreemly low levels.

[dheckman1]

I just watched your video. Take a class. There is no "solar" radiation. You're possibly talking about cosmic - which your hand-held instrument is incapable of seeing. Solar radiation might be light photons, which you would only see using a beta sensitive ion chamber or a GM with a leaky mylar. Bananas contain k-40, granite contains radium which decays to radon, which decays to lead and bismuth that deposit in your lungs. If you want a legal angle, it's that you can't breath bananas.

[antiprotons]

@dheckman1 Just a clarification: Solar Radiation consists of photons and protons of all energies coming from he sun. Cosmic radiation is mostly protons, but can consist of nearly any particle with a half life long enough to be detected. Most background you see on your Geiger counter comes from cosmic and solar radiation. Often, these high energy particles slam into our atmosphere causing particle showers, mostly beta and spallation.

[dheckman1]

Pardon the typo. K-40 gives off a 1.5 Mev gamma, not 2.5.

[dheckman1]

A tool monitor like a Thermo SAM-12 using plastic scintilators will detect the gamma activity in a banana. And our Canberra Fastscan whole body counter sees K-40 banana peaks all the time. Bananas run .3 to .5 nCi/ea. Your problem is background. K-40 gives off a 2.5 Mev gamma that is .1% abundant. If you take a bunch of bananas an crawl in a lead cave, you could likely see the activity with your toy meter.

[dheckman1]

I am a radiation health professional in a nuclear plant. We have done this experiment repeatedly. Four bananas will alarm a tool monitor that is set to detect 5,000 disintegrations per minute (about 2 nanoCuries). This is due to the naturally occuring potassium-40 in the bananas. Most of the areas where bananas grow in South America have high concentrations of potassium. In some areas, people get as much dose from background radiation as a US radiation worker is allowed to receive by law.

[antiprotons]

@dheckman1  I calculate that the average sized banana decays at a rate of about 14 Bq/banana (400-500mg K/banana, ((Avogadro's Number) / (Atomic weight)) x (0.442 g) x (abundance of k40) x (ln 2) / (K T1/2) = (((6.022*10^23 / 39)*0.442) x 0.000117) x ln2 / (3.9357×10^16) = 14.0633 Bq Banana^-1

lol So, you are most correct. 4 such banana's = 3,360 + background probably gets you to 5,000 (scintillation counter?)

[boscostix42]

Bannanas are radioactive, not very radioactive but they contain K-40, a radioactive isotope of K, K-40 is not highly radioactive but its still there

[tnwnl]

I also tried measuring the radioactivity of banana's using a CDV-700 and CDV-Counter. Nothing. Still, anything that contains natural potassium will be (very) slightly above background radiation. That you weren't able to detect it is because you didn't measure long enough or your counter is not sensitive enough.

BTW, a simple Google search tells me that a PM 1703 only detects gamma radiation, it simply won't detect beta radiation from K-40.

[Napalmdeath420]

granite countertops contain uranium which emits radon gas for millions of years and radon gas is the #2 cause of lung cancer in the world. there was a guy who worked at a nuclear power plant that set off the alarms every time that he went to work, they later found out that this was due to a large granite rock underneath his house... now his levels of radon gas were equivilent to smoking 135 packs of cigarettes a day!!! his name was stanley watras, look it up!!

[mrsquirrelsays]

A medium banana contains about 300 mg of Potassium. 0.012% of this is K-40 on average, meaning there are 36 micrograms of K-40 in an average banana. The specific activity is 2.58*105Bq/g, meaning you will get about 9 decays per second. Radioactive, but very slightly.

[ksphysicist]

Okay, I might have missed it in the video, but where is the probe? You have the body of the survey meter set on the potatoes/bananas, but where is the probe?

[ramandu]

He's using a LEni Pro meter...it's a modified (improved) unit combining the Lionel circuit design with an Electro-Neutronics CDV meter from the Civil Defense days. It has a sensitive mica window pancake probe in the base of the unit and a headphone jack that can be used to log CPM....but NOT DOSAGE. The geiger probe is NOT energy compensated.

[TCSRock78]

You also appreciate that when trying to get a point across to the general public, one is better off not to use too many units cause it confuses the readers.

[funkawitz]

I know for a fact bananas have some radiation, I took a tour of Shippingport nuclear power station in Pennsylvania as a boyscout when I was young. They did the banana demonstration there. I remember it vividly, but remember it was very low.

I think your geiger is too weak.

[TCSRock78]

ksphysicist,

The meter is marked in CPM and mrem. It is a pancake probe on the bottom of the meter, right on top of the food items, same one that Ludum uses.

ramandu is one of those guys that learns a little about radiation, then goes around correcting others. As an expert, you know that a rem is a rad is a roetgen when discussing gamma rays in some instances.

[neilamacneil]

I work in a nuke plant, ate a banana at lunch and did a 'whole body count'. I got an 'unusual result, had to repeat the test days later which was clean. health physics said that it WAS the banana and it happens all the time. A whole body count is 90 seconds long and very sensitive.

[TCSRock78]

neilamacneil,

Bull shit. There isn't enough potassium in a banana to affect a whole body scan. Bananas do have potassium, but only .o12 % is K40, the only radioactive isotope of potassium found in nature. That is 12 thousands of one percent. The simple fact is that even a sensitive scintilator like the PM 1703 won't pick up a banana or even a stack of bananas at Walmart.

[81dawgfr]

I beg to differ with you. Neilamacneil is correct. I had a whole body count with an elevated K-40 peak because of a banana. The PM 1703 is sensitive, but not as sensitive as a gamma spect or a whole body counter. There is a small amount of radiation in some foods and it can be seen if the correct instrument is used to measure the radiation. This meter is not the correct instrument.

[eewEinsteineew]

@TCSRock78 I am a physics student, and I tried to identify isotopes on a contaminated old book, with an HpGe detector, we could clearly see a K-40 spectrum that was not coming from our book. It was probably coming from the concrete of from us. I think it should be possible to measure the K-40 in a banana that way.

[pazsion]

Potassium-40 is present as a very small fraction of naturally occurring

potassium, which is an element found in large amounts throughout nature. Potassium is the seventh most

abundant element in the crust of the earth and the sixth most abundant element in solution in the oceans.

It is present in mineral waters and brines, and in various minerals such as carnallite, feldspar, saltpeter,

greensand, and sylvite.

fertilizer, and other sources can concentrate that radiation.

[TCSRock78]

Slogoves,

you are correct, but this video is in response the the Marble Institutes video where they say bananas and potoatoes are hotter than granite countertops.

Just dispelling their lies.

The glassware, tiles and watches can be hot, but few would have tons of the products in their home. Granite countertops can weigh several tons if installed throughout the home.

Fiesta ware is mostly Alpha/Beta anyway, but it is hot.

[slogoves]

I know. but I quote "No Such Thing as a Radioactive Potato or Banana" and you are simply wrong.

[slogoves]

potassium-40 IS radioactive, bananas and potatoes are radioactive but in VERY tiny amounts. bulk shipments of these and other foods have set off radiation alarms at border crossing. ceramics such as tiles and pottery, glass, especially antique glassware with a yellow or greenish color, commercial fertilizers. watches and clocks and smoke detectors. all this came from health physics society's web page.