A Geiger counter set on "beep" is used to show that an uninflated balloons have show no appreciable radiation. One balloon is inflated and negatively charged by rubbing with fur. The control balloon is just inflated.
After 1/2 hour, the balloons are deflated (make a hole in the stem) and placed on the geiger counter. The radon ions in the air are attacted to the charged balloon.
Question:
Where does the background radiation in the room come from?
