Who Invented the Microwave?

Whether for heating a mug of water or reheating leftover chicken or a multitude of other uses, a microwave oven is a perhaps the most popular choice for cooking and heating processes. A microwave oven is a kitchen appliance that can cook or heat food through dielectric heating.

Just like other great inventions over the centuries, the birth of the microwave sprung from an existing technological concept. While conducting a radar-related project around 1946, Dr. Percy Spencer, an engineer of the Raytheon Corporation, had a very interesting observation.

He was doing a test on a magnetron – a new vacuum tube, when he discovered that the chocolate bar in his pocket had suddenly melted. Very curious, Dr. Spencer performed another experiment. Instead of a candy bar, he placed popcorn kernels somewhat near the tube and watched closely as the popcorn cracked and then popped inside his lab. The following morning, Dr. Spencer placed the magnetron near an egg, Together with his colleagues, they watched the egg tremor. The sudden rise in temperature inside the egg caused it to have intense internal pressure. Just as they moved to take a closer look, the egg exploded!

It was a Eureka moment for Dr. Spencer – the melted chocolate bar, the popcorn kernels, the exploding egg – can all be attributed to microwave energy exposure. If an egg can heat up that fast, perhaps so can other types of food.

First Primitive Microwave

Dr. Spencer created a metal box that had opening where microwave power was fed in. Since all the energy entering the metal box had no way of escaping, this created a higher density of electromagnetic field.

As he placed food in the box and the microwave energy entered, the food’s temperature rose quite rapidly. Dr. Spencer had invented an appliance which would revolutionize how cooking was done, and forming the foundation of a multimillion dollar industry.

After his discovery in 1945, Dr. Spencer, through the Raytheon Company, filed for a patent on the microwaving process and soon after, a microwave oven was already set up at a restaurant for product testing.

Around that time however, the microwave oven was almost six feet tall with a weight of over 700 lbs. How inconvenient it would have become, having to accommodate such an enormous appliance in the kitchen. In 1955, they released the first microwave home model – a unit costing $1300. After 12 years, a more convenient and affordable unit was out in the market. It cost $500. 

How Microwaves Work

Microwave radiation is utilized in order to heat water molecules and other polarized molecules that compose food. The main feature of microwave heating is its uniform heating. Microwave heating of molecules in food is able to achieve a uniform and consistent rise in the temperature of food molecules. Microwave heating also speeds up and eases the process of cooking or heating.

Advances to Microwave Technology

Quite surprisingly, the first release of the microwave ovens was not successful until further improvements were employed on the 1947 version after which its commercial sales increased.

With a more convenient and lighter model, restaurants began to see the potential of this very useful appliance. Restaurant owners could now keep food chilled in the refrigerator and then heat them immediately when needed.

Dr. Spencer took the position as consultant with the Raytheon Company until his death in 1970. He had held a whopping total of 150 patents, and continues to be a pioneer and expert in microwave energy. He was indeed a very accomplished man despite not having finished grammar school.

During the early years of the microwave’s penetration on the market, only a few companies manufactured the units and microwaves were dominantly produced by defense contractors because they were the ones who had more access to magnetrons.

Eventually, the sales for microwave ovens rose and even exceeded gas range sales. By 1975, other appliance companies joined the bandwagon and started to manufacture microwave units. Today as many as 90 percent of American homes have microwave units as members of their household.