Anti-Theft Device Keeps Shopping Carts on the Job

Shopping cart wheels are made from the same material as roller coaster wheels. Every cart must be tough enough to haul groceries for a decade. At a cost of $100 each, shop owners are keen to keep these rugged buggies on the job. Meet the hidden device that helps keep them out of the hands of thieves and close to home. MACHINES: HOW THEY WORK Thursdays 10/9c on Science http://www.sciencechannel.com/tv-shows/machines-how-they-work/ Subscribe to Science Channel: http://bit.ly/SubscribeScience Check out SCI2 for infinitely awesome science videos. Every day. http://bit.ly/SCI2YT Download the TestTube app: http://testu.be/1ndmmMq