Microwave Oven

           This common kitchen appliance was discovered by accident. Working at Raytheon, Percy Spencer noticed a peanut chocolate bar he had in his pocket started to melt while he was working on an active radar set. It was the microwaves from the radar, not pocket pool,that caused the gooey mess. He then deliberately cooked popcorn, then an egg. Spencer then isolated the microwaves by feeding them into a metal box, rapidly heating the food placed in it. After Raytheon filed a U.S. patent it had the first microwave oven built in 1947. It was 6 feet (1.8m) tall, weighed 750 lbs (340 kg) cost about $5,000.00, and consumed 3000 watts (compared today's standard 1000 watt) Thankfully, today they are a tad smaller and a wee bit more economical. Because of the microwave, ordinary non-scientific types can now generate the heat of the sun's core with the apple cobbler in a Swanson's TV dinner.

Source: http://gilbertm.hubpages.com/hub/inventions20century