College professors show the geiger counter readings on some common items as a way of diffusing the concern about minute amounts of radiation coming from Japan.
Minute amounts of radiation are now turning up in milk sampled in the United States.
Experts say this is nothing to worry about --yet.
While Geiger counters have flown off store shelves, professors who teach about radiation at Cal Poly Pomona told NBCLA that radiation is already all around us.
They said people should take into account how far away they are from the source of radiation, the kind of shielding that is around it and the levels of it being emitted.
They said, however, unless someone lives in a lead-lined house, one cannot avoid many radioactive objects.
The reason there are not more cases of radiation sickness is because actual exposure is very limited.