Be it about heating a glass of water or baking a cake, a microwave oven is a popular choice for a wide range of heating and cooking processes. It is a kitchen appliance that cooks food by means of dielectric heating. Microwave radiation is used to heat the water and other polarized molecules in food. The characteristic feature of microwave heating is uniform heating. The microwave heating of food molecules achieves a uniform rise in temperature of the food being cooked. Microwaves also speed up and ease the process of heating or cooking.
Percy Spencer, an American engineer and inventor, is credited with the invention of the process of cooking food using a microwave. He discovered the process, while he was building magnetrons from radar sets. While he was working on an active radar set, he found that a bar of chocolate he carried in his pocket began to melt. He deduced that the microwaves from the radar set caused the chocolate to melt. Interestingly, the first food items to be cooked using the Spencer's microwave were popcorn and an egg that reportedly exploded on one of the experimenter's face. Going further with his microwave theory, Spencer designed a high-density electromagnetic field by powering a metal box with microwaves. He observed that the food placed in the metal box heated due to microwave energy.
Raytheon Corporation manufactured the first microwave oven for commercial use. In 1947, it was sold with the name Radarange. It was bulky; it consumed a power of 3 kilowatts and used a water-cooling system. Soon, Raytheon licensed its patents for home-use microwaves. Tappan introduced the first one in 1955. Even these units were bulky and expensive, which made them less suitable for home use. Raytheon acquired Amana Corporation in 1965 and they brought the first countertop microwave oven in 1967. Eventually, many other companies started manufacturing microwaves. They soon reached households of the common masses. They are among some of the very popular kitchen appliances in use today.
A Little about Percy Spencer
He was born on July 19, 1894 in Howland, Maine. He lost his father during infancy. His mother left him with his uncle and aunt. Spencer lost his uncle at a very young age and was raised by his aunt. As a child, he worked at a spool mill to support his aunt. He received very little formal education. Knowing very little about electricity, he was attracted to this concept, on hearing that a paper mill would be using it. He applied for a job with them and acquired it. After reaching the age of 18, he joined the US Navy and soon mastered radio technology. He also studied trigonometry, physics, chemistry, and metallurgy. By 1939, he was an expert in radar tube design and was working with Raytheon as the power tube division chief. During his research on the radar at Raytheon, the microwave technology was discovered. Spencer, an electronics genius, held over 300 patents.
He was married to Louise and they had three sons, James, George, and John. He died a natural death on September 8, 1970, aged 76. At the time of his death, he was in Newton, Massachusetts, United States.