Here is my question from lab: In an experiment, you will use cardboard, copper foil, aluminum plate and lead sheet to block β particles. If you had equal thicknesses of each substance, which would be most effective blocker? Which would be the least effective blocker? I think that the cardboard would be the least effiective and the lead the most effictive. I believe that both copper and aluminum will stop the Beta particles, however my book says "beta particles can penetrate a few mm of aluminum".... does that mean alumimum can stop them too? Thanks in advance!