If you’re anything like me, you’ve probably wondered at some point in your life what the purpose of a cook power button on a microwave is. If you want something less cooked, you’re just going to put it in the microwave for less time, right? The whole point of a microwave is to cook something as quickly as possible without wasting a single minute of your life (that, and making plasma with grapes).
Another thing you have potentially noticed is your microwave’s strange and irritating capability to heat leftovers or frozen meals to insane temperatures in some spots and leave other spots as though they’ve never left the fridge. This is especially annoying if you are microwaving things that cannot be stirred, and if they can be stirred it means you have to put work into a meal that was supposed to be 100% quick and effortless. There is absolutely nothing worse (I’ve been taking hyperbole lessons from Donald Trump [we talk on the weekends]). It turns out the power button was invented to remedy this.
Before I explain the purpose of the power button and how it actually works, let me introduce the tiniest bit of physics. Microwaves use a relatively low-frequency electromagnetic wave (yes, a lower-frequency version of light!) to excite atoms in our food, causing what we call heat. There are a couple of different reasons why our food might come out different temperatures in different spots.
One reason food cooks differently in spots is because of the nature of waves. Think about shining a laser into a box where all of the sides are mirrors. There are naturally going to be spots where the laser beam overlaps as it reflects off of the walls. There are also going to be some spots that are barely touched by the laser (a microwave covers more volume than a laser, but you get the idea). This is why almost every microwave has a turntable. The turntable tries to help move the food through all of the spots that are getting more microwave traffic. The turntable does not do as much good if our food is a mixture of different substances though. This brings us to the second reason food cooks differently in spots.
Different foods absorb energy at different rates. Water is great at heat absorption. Food that contains more water will heat faster and more efficiently. This is why your rice that has sauce on it is going to heat rather quickly while your poor sauceless rice is still going to be cold. Thin crust pizza is another good example. Your toppings may get nice and hot while your crust remains cold.
While water is great at absorbing energy, frozen water does not heat up as quickly. To keep things short and sweet, frozen water molecules are not as free to move (i.e. cause heat) as liquid ones. This brings us to the topic of microwaving frozen foods (defrosting chicken, for instance). Leaving frozen food in the microwave for a longer period of time may seem like the obvious solution to heating up frozen food. You may run into some problems doing this though. When ice melts, it turns into water (fun fact). As we’ve learned, water heats rather quickly. As soon as the water in your frozen food starts melting in places, those places get really hot really quick, while the rest of the food remains frozen. You could potentially start cooking random pieces of your chicken while the inside sits frozen solid (to the literature buffs out there, think Dante’s Inferno).
There are a couple of solutions to these problems we face while microwaving food. With some foods (rice, mashed potatoes, noodles), we can pause the microwave to stir and let the heat dissipate. This can sometimes be required several times while microwaving to keep certain parts of the food from getting too hot. Other foods cannot be stirred (chicken, pizza, pies). The only solution to letting the heat dissipate evenly is stopping the microwave every few seconds to let the heat spread from the really hot parts to the cold parts before the hot parts get TOO hot. If only the microwave had a feature that would do this automatically…
Enter the cook power button. This button does not actually have anything to do with the heating capabilities of the waves being emitted from your microwave’s magnetron (cool name, huh?). In other words, a low power setting is not going to send out a less “powerful” microwave than a high power setting. Instead, it acts as your replacement for stopping and starting the microwave to let the heat dissipate! If you put your microwave on a lower power setting, you may hear its sound change from time to time. This is the magnetron turning on and off. This oscillation from on to off allows the heat in the hot spots of your food to spread to the cold spots before the hot spots get too hot. If you use the defrost button on your microwave, you’ve probably already heard your microwave’s magnetron turning off and on without realizing that’s what it was doing (this is because the defrost button automatically uses a low power setting).
So, there you have it. After a lifetime of owning a microwave, you finally know how to use it to its fullest potential. And if you’re anything like me, you’ll soon begin to know your microwave’s capabilities on a whole new level. It becomes a game each time of figuring out exactly what power and what time it takes to cook things to the perfect temperature (I’m proposing the game for the Olympics next time I speak to Mr. Trump).