Science Cafe Cookin' With Microwaves

Jun 22, 2015

Another in the National High Magnetic Field Lab's popular "Science Cafes" takes place in Tallahassee this Wednesday evening (6/24/15). The topic will involve a force of nature that all of us make use of every day.  That force is known as microwave radiation.

Mag Lab Director Greg Boebinger speaks at a previous Science Cafe.
Credit National High Magnetic Field Laboratory

Microwaves have been around since the beginning of time.  In fact, it was the lingering presence of microwave radiation left over from that beginning that helped scientists confirm the Big Bang; that's the theory, not the TV show.  One of the first practical applications of microwaves came during World War Two and the invention of radar.  Mag Lab Researcher Thierry Dubroca explained a peculiar characteristic of microwaves soon led to their being the basis of another invention after the war.

“If you scan the frequencies in the microwave region you’ll see there are absorption peaks,” he said.  “That means there are frequencies that do not work and that just happens to be because of the moisture in the air.  And so for radar, you want your microwaves to go and come back so you avoid those frequencies that are absorbed by the water.  And I guess someone was clever enough to think, ‘What if I do the opposite; I picked a frequency where it’s absorbed by the water and I’m using that to boil the water and why not heat food?’  And that’s how the microwave oven came about.”

In fact, the very first microwave ovens made by the Amana Company, were called "Radar Ranges".  Microwaves are also useful in communications.  The radio broadcast of this story depended on a microwave link between WFSU’s Tallahassee studios and the station’s transmitter in Jefferson County.  And without microwaves, Dubroca said our super-sophisticated cell phone networks would not exist.

“We currently use the 4G network for wireless telephone and data.  That’s in the low frequency microwave area, so it’s higher than radio frequency but it’s the lower end of the microwave.  And the 5G, which will be the next generation that will come in 5 to 10 years that companies are trying to put together to have more data, you can have more resolution on your screen, watch live videos and at the same time maybe surf, although I don’t know why you’d be able to multitask so much at the same time.”

But the capability will be there if you need to. However, because microwaves are invisible and mysterious to the average person, Dubroca said there is fear.

“A lot of the fear that people have I feel comes from them not knowing, so they look around at people spreading rumors and even before there was the Internet there were rumors.  The microwave oven came in the 1940's and there was a big scare about what it does, even to the food.”

So Dubroca will be fighting fear and fantasies about microwaves with facts at the next Mag Lab Science Cafe.

“It will be covering the historical account of microwaves, it will be covering how the scientific process happens, how does that translate into a technology and how does that translate into an application that we eventually use.”

Dubroca's talk, "Popcorn, Radar and Cell Phones: How Microwaves Rule the World" takes place at the Backwoods Bistro on East Tennessee Street Wednesday evening.

“6:15 p.m. - 7:30 p.m. and it’s free to get in.  Everybody’s welcome.  The level and the depth is going to overwhelmingly be for a general audience.”

There's a cash bar with adult beverages if you're so inclined.  And since there will be at least one microwave oven as part of the presentation, there will at least be some popcorn floating around.