So a non-physicist posed a question to me the other day. He said that he heard something once that if two pennies are within close proximity of a magnet for at least a few hours, they gain some magnetic charge. When removed, they will slightly attract or repel one another. So I tried it. I left a penny on a magnet for 48 hours. When I removed the penny, it was able to deflect a magnet when it was held near it. Why does this happen?