How Do Vending Machines Detect Fake Coins?

MACHINES: HOW THEY WORK Thursdays 10/9c on Science This machine can decipher coins with pinpoint accuracy. Light sensors measure the size while electromagnets detect the metal type of the coin. More Machines! http://www.sciencechannel.com/tv-shows/machines-how-they-work/ Full episodes streaming FREE on Science GO: https://www.sciencechannelgo.com/machines-how-they-work/ Subscribe to Science Channel: http://bit.ly/SubscribeScience