Nothing seems to excite visitors to science museums, or viewers of science or science-fiction films, more than the sound of a clicking radiation monitor. Few can differentiate whether the amount of activity being detected is negligible or is in the dangerous range
At the Nuclear Heritage Museum we have a number of radioactive artifacts ranging from small chunks of uranium ore to a clock face with radium-painted digits, and even tableware that pre-1960 would have uranium or thorium added to the raw material or glazes to enhance the colours.
We sometimes tell our visitors to the museum that by their presence they have increased the “radioactive load” of the facility and that if they happen to need to use our “facilities” they are “natural radioactive emitters”.
All humans have potassium and carbon in the makeup of their bodies. They inhale/ingest these elements on a daily basis and in turn emit them in various forms. Potassium-40 and carbon-14 are two radioactive isotopes that are naturally in these materials. Potassium-40 has been with us since the earth was formed, while carbon-14 is generated continuously by energetic particles from space, and has done so for as long as our mainly-nitrogen atmosphere has existed.
An average human body typically contains 140 g of potassium of which 0.012% or 17 mg is potassium-40. Carbon is much more common in our bodies and the average human contains about 48 kg. The fraction of carbon that is carbon-14 is, however, very small – typically 1 part per trillion (12 zeros). Nevertheless, even that small ratio still results in about 0.5 micrograms of carbon-14 being carried around by each of us. It is enough that, if some archeologist many centuries from now came across your body, they could pinpoint your date of birth relatively accurately by measuring the remaining carbon-14 in your bones.
The visitor capacity limits of the museum at 51 Poplar are such that we would never have enough visitors at once to make the total potassium-40 or carbon-14 load even remotely of concern so we invite you to visit at any time without any such worries. Tours can be arranged by contacting one of the Board members or sending an email to nuclearheritage.com
