Question 1: Do you think the radiation featured in this video (americium-241, btw) is alpha, beta or gamma radiation?
Question 2: What’s the purpose of wearing gloves during this experiment?
Answer 1:
Notice how the count rate decreases rapidly with distance? The radiation must be alpha, because we know that alpha radiation can be blocked by just a few cm of air, or just a piece of tissue paper. If it were beta, a few cm of aluminium would be required. If it were gamma, even a few cm of lead would not absorb it completely.
Answer 2:
The purpose of wearing the gloves is not to shield my hand from the radiation. That is achieved merely by keeping my hands a few cm from the radioactive source (which is why pincers were used to handle the radioactive source). Instead, the purpose of the gloves is to prevent accidental contamination of my hands or cloths and subsequently accidental ingestion of radioactive nuclide.
P.S.
The source is actually Americium-241 obtained from a smoke detector. Am-241 is an alpha-emitter with a half-life of 432.7 years. It does emit a little bit of gamma radiation. Its daughter nuclide Neptunium-237 is a alpha-emitter with a half-life of 160 000 years. The grand daughter nuclide Protactinum-233 is a beta-emitter with half-life of 27 days.
xmPhysics 