Tuesday, July 31, 2007

How Does a Microwave Oven Work?

Sorry about the delay in posting. There has been much to do in the scientific world of Dr. Dave. Plus the last Harry Potter book came out and, well, I had to read it.

In an earlier post about Pyroceram, I said I would explain how microwaves work. As promised, here it is!

Microwave ovens are a cool invention that makes cooking food really simple and fast. You can use a microwave oven to heat things in a matter minutes compared to the longer cooking times in a normal oven (called a convection oven).

So how does a convection oven work?

Convection ovens work by heating the air inside it using fire or electricity. When heated to the desired temperature, food is placed inside so it can cook.

convection-oven.jpg

Have you ever thought about how food cooks in an oven?

Let us imagine we are baking a cake.

After making the batter, it is poured into a pan, which is placed inside a preheated oven. The hot air surrounding the cake batter warms the outside first. Eventually, the insides will get hot. If you do not bake it long enough, the outside may look like it is ready, but the insides could still be batter!

Microwave ovens, unlike a convection oven, do not get hot. Instead, it uses microwaves (strong radio waves), which have the special ability to pass through things like ceramics, glass, and some plastics. More importantly, microwaves have the ability to make water, sugar, and fats inside your food spin and move.

So how does the food get hot?

Try this little experiment. If you rub together really fast, your hands will get warm because of friction.

Now imagine the water, sugar, and fats inside of your food rubbing against each other millions of times every second. Most food gets cooked in a microwave for one or two minutes. That’s 60 to 120 seconds, which means that the water, sugar, and fats in your food is causing a lot of friction, which makes heat that can cook your food.

If you think about it, microwaves ovens cook your food from the inside!

Now that’s cool.

Dr. Dave

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