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Comment by 52-6F-62 | Hacker News Reader

Yes we need documentation like this.

When I was younger I worked in a warehouse. In that warehouse we had a break room. In that break room we had a microwave that was not in good working order. The mechanism that would stop the machine from emitting microwaves when the door was opened had failed, and instead of fully disabling the machine out of safety it would allow it to continue to run with the door wide open.

One day a coworker had been heating up some food and wanted to check on it, so he opened the door while it was running and stuck his head inside. Right inside. I had to holler at him to stop and pull his head out. Of course he was in no immediate danger, but I'm sure rotating all those water molecules in your brain can't do much good... those things do bake potatoes after all.

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The biggest danger is generally to your eyes because they contain significant water content but lack the circulatory cooling found in other parts of the body due to the need to be transparent. Looking into a running microwave with the door open can pose a cataract risk.

https://www.fda.gov/radiation-emitting-products/resources-yo...

Oh, yes.

Think of what happens to the clear "white" of an egg (proteins + water) when you heat it up.

Which clear parts of your eyeballs (also proteins + water) would you be okay with that happening to?

Interesting. I wonder if looking too closely into a fire carries the same risk.

Infrared eye protection is important for glassblowers looking at molten glass [1]. Back of the envelope math suggests that an occupation that required staring at an intense fire for long periods of time would violate the same workplace safety thresholds, but I have not been able to locate any studies that specifically investigated looking at fire.

There are a surprising number of different jobs that involve staring at incandescence from molten glass or metal, but I think the most interesting is an operator of a disappearing-filament pyrometer [2].

[1] https://www.sciencedirect.com/science/article/abs/pii/S02755... [2] https://en.wikipedia.org/wiki/Disappearing-filament_pyromete...

And if you are a man, your balls - which must be kept below body temperature - even raising them to 37C/98.6F will reduce fertility - heating them with microwaves goes far beyond that modest risk.

I don't know if that's just me, but I have a reptilian reflex to never put my head in any box or cavity of a powered device.

Take a good look at your hands. Hold them both up, turn them over, study the fingers and the palms and the wrists.

Now decide which one you could stand to do without.

That's the hand you stick into cavities of powered devices.

Machinery maintenance tip: before you stick your hands in, hit the go button. You should know that nothing is going to happen when you do, but you should do it anyway in case you're wrong.

personally i'd use sticks unless I need finger precision

I mean, in all honesty, when I occasionally find myself stopping and considering for a minute whether something I'm doing is safe, if I do decide "eh, it should be fine," I will switch to using my off hand.

In construction, it’s “never put your hand where you wouldn’t put your dick”.

A reflex nobody could fault you for having, to be sure.

Leave the rapid heating radio waves for the roti.

I've often wondered about putting it between two bluetooth earbuds or next to a cellphone...

I don't know what the orders of magnitude power are, but I wonder about power vs time.

phones are sub 5w, even assuming it's a linear relationship you have 100-400x time less energy

I forget which either ravens or crows are the same way one of those birds won't put their head in any enclosed space.

Radar operators in the Arctic learned that they could stay warm by standing in front of their antennas. The first microwave ovens were called "Radar Ranges".

The fact that these guys are still alive is pretty strong evidence for how safe non-ionizing radiation is, even at high strength.

At least when you're not sticking your head into a box that is meant to contain those waves and concentrate them in order to heat up water-laden organic matter.

in my experience they seem to be more efficient at super-heating ceramic plates than water filled organic matter which still manages to be frozen in the center

The key is to use programs for cooking rather than max power. The programs will use variable power levels to achieve more "even" cooking/reheating.

I read that the heat/cool heat/cool pattern of the 50% power level cooking for twice as long helps the heat to dissipate into the food, melt the ice crystals, and gives a better overall experience for taking 2x the time to cook the food.

I've not put that to the test myself with any scientific rigor but I have noticed better results with it personally.

Ice is far less absorptive than liquid (out I think even gaseous) water. First thaw, then cook.

Also, use borosilicate glass instead of said ceramic.

It's all a matter of degrees. People love to bathe in sunshine, but when someone builds a mirror powerful enough to boil water, it would be wise to keep your head and limbs well out of the focus.

My grandfather was an EE involved in early radar/microwave comm research and repeatedly used the beams to warm his hands and feet when in the field. He was exposed to who knows how much and developed serious sensory and circulatory problems later in life, as well as an unknown brain issue.

He was also around some of the overly-exuberant government tests of troop exposure to the immediate after-effects of atomic fission.

https://upload.wikimedia.org/wikipedia/commons/7/73/Exercise...

There is a long standing dispute between WW2 engineers at Raytheon vs. those at the UK's Telecommunications Research Establishment [0] about who was the first to cook sausages on a radar set.

(I previously worked at one of the modern successor organisations to TRE. I distinctly remember as a very young software engineer being told by an elderly staff scientist that his purpose in life "was to help confound the Queen's enemies and keep the poor bugger on the battlefield alive whilst he did so")

[0] https://en.wikipedia.org/wiki/Telecommunications_Research_Es...

One of the first uses of microwaves for heating was to humanly heat hamsters that had been cryogenically frozen.

Back in college, there was a food truck on campus that had a microwave in it where the owner had cut a hole in the door. They would set the timer for 99 minutes and just take stuff in and out whenever it was ready. Much faster than constantly opening and closing the door.

fuck it's so good I didn't know about this when I was a cook.

Yikes. If you saw something like this, you could probably legitimately file an FCC complaint (in addition to a complaint to your favorite worker safety bureau). That was probably causing all manner of EMI in 2.4GHz

Microwaves have two door switches to stop this happening.

If one fails, the microwave will still whir and the turntable turn and the light on, but the actual magnetron will be disabled. That's probably what happened to yours. If he actually had his head in an 800 kilowatt microwave turned on, even for 1 second, I doubt he'd have any vision left.

> 800 kilowatt microwave

I hope this is a typo...

Maybe. 800 kilowatts means there would be nothing left. I'm sure that there's some industrial- or factory-grade microwaves that are 800 kW.

Keep in mind that microwaves have lower frequencies than visible light or even infrared.

Radio -> Microwaves -> Infrared -> Visible light -> UV -> X rays -> Gamma rays.

I wonder how this happened. I repaired two (consumer-grade) microwaves, and both of them had 3 independent switches:

- one was sending signal to controller

- second was cutting power to something (presumably magnetron) when released

- third was short-circuiting magnetron when released, it would cause fuse to blow if it ever got energized

I assume the mechanical parts were aligned such that if you open a door, the second switch was released before the third one.

The point of the design is that firstly if you try to defeat the interlock you will cause a short circuit, unless you carefully activate the switches in the proper order as the door would, and secondly a programming or other fault in the controller can never activate the magnetron with the door open.

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