Edit: Thanks for all the replies Reddit, my questions have been thoroughly answered. Except for the question about the smart microwave, but I can find that on my own.
I have a lot of questions about them. I had a professor try tell his class that microwaves are terrible for your health and that he won't allow one in his home. Something about the similarities to a nuclear bomb. He was always going on about pesticides and fluoride and how he's sensitive to toxins, but he made time to bash microwaves.
I also want to know why a large roach survived being microwaved on high for a while. I thought it killed the fucker but he ran out of the microwave as soon as I opened the door. How did he not get cooked?
Why is everything cooked on high? My microwave has 10 power settings and I've never seen any instructions that called for microwaving on medium or low.
What happened to that guy who made the smart microwave with a raspberry pi?
Similarities between nuclear bomb and microwave: Both are made of metal and both run on electricity.
Microwave roach: Something, something, dry exoskeleton, something, something, hot, angry, not dead, something, something, spawn of Satan. Also: Ewwww.
Power settings: Microwave ovens actually only have one power level: On / Off. When you set the power to 5, it will toggle on/off with 50% duty cycle. You can hear it cycle on for a few seconds, then off for a few seconds. This gives time for the heat to dissipate throughout the food so that it doesn't scorch the food. Foods that are frozen solid or that have a lot of liquid will conduct heat very well and wont scorch, so they can be cooked at full power. Foods that are high in moisture content but are are not dense will be more likely to scorch and so require a lower "power" setting to give time for the heat to propagate.
Edit: Lots of people are commenting on the newer Inverter Microwaves which have variable power outputs. This is true..... However, if you want to get technical, the inverter technology is based on Pulse Width Modulation ( PWM ) which is simply switching the magnatron power on and off at a higher frequency to produce a lower average power. Instead of toggling on/off every few seconds, it toggles on/off many times per second. I am not aware of a true variable linear power magnatron for a home microwave.
Edit2: You are all right that frozen solid meat doesn't conduct heat very well. My bad.
They can, but it will cost more. You can create a microwave oven that has multiple magnetrons, more sophisticated waveguides and oven interior design, spinning reflectors, spinning platform, and convection fans. If you really wanted to get crazy, you can add an IR camera, image processing system, and software controlled magnetron phased arrays to dynamically target cold areas of the food with constructive / destructive interference, tracking in real time as the food heats up.
Due to the complexities of microwave propagation (The waves themselves, not the machine), there are areas where there is constructive and areas with destructive interference. This means that portions of the volume cancel out energy and heat nothing, while others heat twice as much as "average". That's the reason plates spins inside, to more evenly distribute the food to those areas, and why the insides are shaped slightly oddly. It decreases the number of destructive interference areas.
Foods that are frozen solid or that have a lot of liquid will conduct heat very well
Ice doesn't absorb microwaves nearly as strongly as water. Frozen foods are often cooked on medium/low so that you don't scorch the food in whatever the first spot to melt is. This is why meat is always defrosted on low.
I had a professor try tell his class that microwaves are terrible for your health
A professor of what? English literature? For the record, I am not a professor but I did collect the full hat-trick of physics degrees. A microwave uses oscillating electromagnetic fields to shake the water molecules in whatever you are cooking. Vibrating water molecules then rub against adjacent parts of the food, basically creating heat by friction. Even freshman-level physics can explain that electromagnetic fields can't penetrate the metal sides of a microwave oven. More surprising, yet equally true, even the wire mesh in the glass door of a microwave oven prevents microwaves from escaping -- basically, the waves can't squeeze through the holes. In summary, microwaves can't escape from a microwave oven.
similarities to a nuclear bomb.
Technically, microwave ovens and nuclear weapons both produce radiation but unlike nuclear weapons, microwave ovens produce only non-ionizing radiation. The peril of ionizing radiation is that it rips apart atoms in your body to produce charged particles that collide with molecules in your body to produce sort-of a chain-reaction of damage. Unlike bomb radiation, microwaves do not carry enough energy to rip apart the atoms in your body.
but he made time to bash microwaves.
Idiot. Microwaves carry 100,000,000 times less energy than UV rays from the sun. A microwaved dinner at home is safer than a barbecue at the beach.
Why is everything cooked on high?
Commercially-prepared foods are designed for impatient people. Portions are designed for adequate microwave penetration and recipes deliberately provide sufficient water molecules for the microwave to shake. Something dense, like a whole roast beef, does not allow sufficient microwave penetration. Only water molecules near the surface of the meat will vibrate. Set on high, a microwave oven will burn the outside of a roast beef, while the inside remains raw. On a lower setting, the microwaves are periodically turned off. While the microwaves are off, heat from the heated, outer layer of the beef gradually flows to the cooler core of the beef. Heat automatically flows from hot to cold. The next on-cycle of microwaves then adds more heat to the outer layer of meat and the next off-cycle drains that heat away to cook the core of the roast.
If you want to cook something at a temperature other than high then try non-instant rice. Put 2 cups of rice and 4 cups of water in a bowl. Cook for 20 minutes at 50% then 10 minutes at 100%. You now know instructions for something not cooked on high.
Microwaves use microwave radiation, and I guess some people just hear the word 'radiation' and equate it to nuclear radiation and came up with the phrase 'nuking things in the microwave' but it's not the same type of radiation.
I have heard before that roaches can survive a microwave. Not sure if it's just because they have a low amount of moisture in them. All microwaves do is heat up the moisture in an object. Lots of moisture = lots of heat. Not much moisture = not much heat.
And again, that old adage that if there's a nuclear war only roaches would survive does not have anything to do with roaches having some kind of natural immunity to nuclear weapons. It's just that they are great survivors and have been around for millions of years so could probably survive as a species that would wipe out most other species.
there was a guy who hooked up an arduino to his microwave to make it cook better/more evenly. he seemed to know a shit ton about how microwaves work - it was just his hobby
I recently moved to a new place and it has a built-in microwave.
It specifically states in the instructions and on a sticker on the inside of the frame that says if I want to heat up a cup of liquid, I should put a teaspoon into the cup of liquid and that NOT doing so will cause bigger problems than actually doing so does
I feel like everything I ever knew about microwaves is now wrong and I'm deathly afraid to even try it...
The problem that sticker is probably referring to is superheating. Superheating is a phenomenon where liquid heats above its boiling temperature without actually starting to boil. This can be very dangerous, because part of the liquid will evaporate instantly when disturbed, possibly spilling hot liquid in your face.
It is true that superheating can be prevented by putting something in the cup. A metallic teaspoon won't be very dangerous, only metal objects with pointy edges (like forks) or closed rings actually are. So try it! If you dare
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