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About "Ask A Scientist!"

On September 17th, 1998 the Ithaca Journal ran its first "Ask A Scientist!" article in which Professor Neil Ashcroft , who was then the director of CCMR, answered the question "What is Jupiter made of?" Since then, we have received over 1,000 questions from students and adults from all over the world. Select questions are answered weekly and published in the Ithaca Journal and on our web site. "Ask A Scientist!" reaches more than 21,000 Central New York residents through the Ithaca Journal and countless others around the world throught the "Ask a Scientist!" web site.

Across disciplines and across the state, from Nobel Prize winning scientist David Lee to notable science education advocate Bill Nye, researchers and scientists have been called on to respond to these questions. For more than seven years, kids - and a few adults - have been submitting their queries to find out the answer to life's everyday questions.

Previous Week's Question Published: 8 October, 1998 Next Week's Question
Microwaves heat by agitating molecules
Question
How do microwave ovens work?

Question
When you put a mug of water in the microwave oven and turn it on for a few minutes, you get a steaming cup of water. How does the water get heated up? Well, a microwave oven generates microwave energy that interacts with the water molecules. Microwave energy penetrates the mug and jiggles the water molecules. This agitation creates friction which heats up the water. The microwave energy is made of an oscillating field that agitates molecules such as water that have a positively charged and a negatively charged end. Such molecules are called polar molecules. When you put a piece of food in the microwave, the microwave energy jiggles the water molecules in the food and heats up the water which in turn heats up the food. That's why people say to sprinkle a little water on food before microwaving it. Microwave ovens work as well as they do because microwave energy can penetrate through our food containers and food so that they can interact with the water in our food. If you put a thick piece of meat in the microwave oven, the microwave energy only travels about an inch or so into the meat before it is absorbed by the meat, so it only cooks the outer inch or so of the meat. Microwave energy also heats up drops of grease to temperatures of 100°C and thus can cause the scarring that is sometimes seen on plastic utensils.

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