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Dodging Microwaves

Stuck in a microwave oven? Here’s how not to get cooked.

Badri Sunderarajan
Sep 3, 2017 · 7 min read

If you get stuck in a microwave oven, don’t panic. As an ant, your body is small enough to take the rays for a short while. The important thing is to get to a cooler spot as soon as possible, without running around aimlessly.

Microwave overs are used by humans for processing food. Humans have weak digestive-systems, so they can’t eat as many varieties of food as we do. Of the things they can eat, many are hard for them to digest. And, to add to it all, humans are especially vulnerable to infection from bacteria.

That’s why humans often change their food before eating it, in a process known as ‘cooking’.

The main idea behind cooking is that you heat the food enough for it to change its form. Parts of it may melt, or get softer, or generally become easier to digest. As a side-effect, cooking also gets rid of harmful bacteria. They can’t stand the heat.

Humans seem to be the only animals who do cooking. Of course, we sometimes let food lie for a few days, allowing it to decay into a more digestible form. The heat-treatment, however, is something unique to humans. Early humans probably cooked over open fires: humans are the only animals able to create and control fires at will, and evidence of cooking-fireplaces dates back to 400,000 years ago.

As humans cooked, they also got more dependent on cooking. They became less able to digest food. And nowadays, they’ve gotten so used to it that they cook food even if it doesn’t need to be cooked, and seem to prefer eating food while it’s still warm. All these things might seem like disadvantages. But cooking also holds a great benefit for humans.

Cooking is a bit like pre-digesting food before it’s eaten. When humans eat cooked food, they don’t have to spend so much time and energy digesting it themselves. And that saved energy can be used for other things, such as keeping their huge brains running.

There’s even a theory that thinks cooking was what started off human civilisation. It gave them more free time to do other things, and also let their energy-hungry brains grow larger. There’s only one problem with the theory: human brains started growing bigger before the earliest evidence of cooking. But then, we may just not have found the earlier evidence yet. In any case, we’ve been eating human-cooked food, too. So that part of the theory fits.

As humans became more dependent on cooking, they also made more sophisticated devices to do the cooking for them. Simple fires made way for wood stoves, and then gas stoves, solar cookers, electric ovens, and all the rest.

One of the most recent ones is the ‘microwave’.

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Microwave ovens are called ‘microwaves’ for short, but the real microwaves are the things the ovens uses to cook food. They’re really electromagnetic waves — just like visible light and radio-waves, but larger and more powerful. Their method of heating is different from any other method.

Instead of heating the food, they make the food heat itself.

Ordinary ovens, stoves, and cookers work by becoming hot themselves. They heat up using fire, electricity, or energy directly from the Sun. That heat then spreads slowly into the food.

At least, some of it does. The rest just hangs around in the cooking machine or is lost to the air.

Because of the way it spreads, there’s no escape from the heat. So, don’t even step into an ordinary oven. You wouldn’t stand a chance.

Microwave ovens, on the other hand, use microwaves. Those rays work like ordinary light, but with a few important differences. Because they’re more powerful, they can travel through many opaque, solid things — like rice and dal — in the same way light travels through glass. Metal is too strong to let them pass, but they can travel effortlessly through plastic.

That gives us a good rule of thumb. If a human picks you up along with their food and puts you inside an oven, then look at what kind of dish your in.

Metal dishes are used for ordinary ovens. They’re better at letting the heat through, and anyway, plastic would begin to melt with the high temperature. For microwave ovens, on the other hand, plastic dishes are best. They let the microwaves in through their walls. If the dish were a metal one, the microwaves would just bounce off and never reach the food at all.

That’s also the reason microwave ovens have metal walls: so that the rays of microwaves get reflected back inside without escaping. The ovens also have a metal grill in front for humans to look through. Light rays are small enough to travel through the grill holes. The microwaves, which are larger, stay trapped inside with the food.

But how do the microwaves work, once they do reach the food? It’s all to do with the molecules.

Almost everything you see in the world is made up of molecules. Water is made up of water molecules, and aluminium is made of aluminium molecules. Ants are not made up of ant molecules, but out of many different kinds of molecule put together in a very specific way, like Lego blocks from an Eiffel Tower kit snapping together to make a complete, perfect, model.

Now, it so happens that some of these molecules are electrically charged. These are called ‘dipoles’ because they have two poles, like the North and South of a magnet. Water, so commonly found in food, is a dipole. Plastic isn’t. That’s why food gets heated in microwaves while the container it’s in remains cool.

Dipoles can get influenced by microwaves, because a microwave is an electromagnetic wave.

An electromagnetic wave. It’s made up of electric and magnetic fields, each following the other, and switching between positive and negative values, over and over again.

As microwaves pass through, they attract the dipoles like magnets. But because they’re switching back and forth, the dipoles start turning back and forth too.

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They go on and on, faster and faster. And as they move, they bump into other molecules, making them move as well. When something is ‘hot’, it means its molecules are moving faster. So what the microwaves have done by speeding these molecules up is what we, in our huge size, call “heating it up”!

Unlike other ovens, which heat something first and then let the heat spread, the microwave oven does it by directly moving the molecules themselves.

And now, here’s the crucial part: the microwaves are not spread evenly all through the oven. They shoot out from certain fixed points, like rays of light from a torch. Even when they bounce off the oven walls, they don’t fill up all the space inside. Instead, they form a ‘standing wave’ — a path that stays in the same place, just as a river stays in the same place and travels the same route even when the water inside is constantly flowing.

This basically means there are always some hot spots and some cold spots all through the microwave oven. That’s why the ovens have a platform to turn the food round and round: to give all sides some exposure to the rays. If it wasn’t for the turning, ‘microwaved’ food would never get cooked evenly.

Your job, by contrast, is to get cooked unevenly. Or rather, not get cooked at all.

On a turning platform, the job can get difficult. The trick is to keep running in a direction opposite to the turning so that you remain in the same cold spot, as if you weren’t running at all.

If that sounds a bit overwhelming, don’t worry. You’ll be fine, as long as you remember the main point: stick to the cool areas, and keep away from the warm ones.

There is one caveat, though: Don’t end up in the middle of the food. It starts out cool, but that quickly changes.

As microwaves travel through food, they also lose their power - in the same way that light becomes less in the deep sea, and a torch fades away into the night. If the food is very thick and dense, then no microwaves will reach its centre at all.

That food won’t get heated directly by the microwaves, but by the hot food around it. That means it’ll take some time for the heat to get to it and so will stay cold for a while.

That’s the ‘cool’ area you’re not supposed to go to. It may seem cool at first, but it will warm up. Eventually. And then you’ll have no escape, because all the exit routes will be even hotter!

Which brings me to the final rule of microwave safety: stand outside the food. All the food will get heated eventually. That’s the point of the microwaves, after all. But because of the way microwaves work, the rest of the oven will usually remain cool.

So, now you know what to do if you ever get trapped inside a microwave oven. It’ll take quite a lot of running and even more risk, but sometimes, it’s worth the effort. You’ll get a lot of food and the end of it.

And, it’ll even be cooked.

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