> The functional principle of a microwave oven is dielectric heating rather than resonance frequencies of water, and microwave ovens can therefore operate at many frequencies. Water molecules are exposed to intense electromagnetic fields in strong non-resonant microwaves to create heat. The 22 GHz resonant frequency of isolated water molecules has a wavelength too short to penetrate common foodstuffs to useful depths. The typical oven frequency of 2.45 GHz was chosen partly due to its ability to penetrate a food object of reasonable size, and partly to avoid interference with communication frequencies in use when microwave ovens became commercially available.
I was very surprised reading this because my school's textbook claimed that microwaves heat food using the resonant frequencies of water. This fact was drilled into our heads over the course of multiple tests. It's disappointing that millions of students every year still learn this incorrect explanation.
The "taste zones" of the tongue misconception makes me the most angry. We were taught this in school. I remember having to color in areas of the tongue.
And yet any of us could've very easily disproven this and it doesn't correspond to our experienced reality and yet we all believed it because we had be taught it in school.
This was one of our introductions to the scientific method and an experiment we actually conducted as well. I remember it making no difference to me but pretended it did due to peer pressure.
I wonder if false teachings like this can create a mistrust in science from an early age?
Me, it is the false explanation of how plane flies, the equal time transit.. I had an physic exercise in school based on this, I was so angry..
I told the physic teacher that there is no leach between the top molecule and the bottom molecule which would make then rejoin at the same time after the wing only to be answered by a blank stare..
That Wikipedia entry is a list of things that many people believe are true, but are definitely false.
We also need a list of things that many people believe are true, but have no scientific basis. I.e., things that may be true or false, but no study has shown conclusive evidence either way. The medical and personal health fields are overflowing with things that people believe for which there is no evidence.
> things that may be true or false, but no study has shown conclusive evidence either way
Ah, like most of history...
"We are sorry for the inconvenience, but we currently lack objective sensors to send back in time and gather data for an evidence-based approach. We regret to inform you that our history department will be closing after critical objectivity is reached on our campus, anticipated in September of..."
...never. Subjectivity is a natural law, it's universal to the experience of the life form. Objectivity in science is a code name for "measurements that facilitate social bond-building" and while this has its place, the other subjective, theory-generating, guessing-supposing-believing half of our reality cannot be repressed if the results are to be qualitatively "good." We need to become comfortable with, or simply continue to develop as best we can, the deeply organic and chaotic question of quality if we are to evolve beyond current objective limitations. Until then, even "hard science" when pushed to drive out all subjectivity will continue to be filled with scandal, the dark appearance of the subjective realm. The best we know of good must be taught or the repressed spectre will spring us right back to the worst kind of jihad, it will continue to give us the physicists who joined Aum, etc.
> Microwave ovens do not cook food from the inside out. 2.45 Ghz microwaves can only penetrate approximately 1 centimeter (0.39 in) into most foods. The inside portions of thicker foods are mainly heated by heat conducted from the outer portions.
I think the main reason this myth persists is stuffed/filled food items such as pizza rolls, burritos, Pop Tarts, Hot Pockets, etc.. With these, there's typically an outer layer that is thermally insulating and lower-density, while the filling is more thermally conductive and higher-density (water/fat). This means that even if the temperature is uniform, the filling will be perceived as much hotter than the outer layer.
Microwaves work by heating the polar molecules in liquid solution, which essentially means water in food. If you've got food with some kind of crust, the crust tends to be dehydrated. Consequently, the crust doesn't get much heating, particularly when compared to the internal melange.
In that vein, it's not really wrong to say that the food is cooked from the inside out, so long as you don't understand to mean that it is literally cooked from the exact middle. The heating is still coming from the interior which is conducting heat to the exterior shell; that's it the outermost layers of the interior filling that's heating, not the innermost layers, is a minor detail by comparison.
I think, more practically, it's that this characteristic of heating is in stark contrast to traditional ovens, which are very much exclusively outside-in, no matter the composition. That is, "cooking inside out" is useful as a heuristic even if, pedantically, a misconception.
I routinely use a microwave to pre-heat the inside [1] of something before finishing it off in an oven or toaster oven (sometimes in convection mode). That way, I gain the vast majority of the benefit of speed from my high-powered microwave along with the mouthfeel and caramelization benefit of the traditional oven.
The contrast can be particularly stark (and useful) when working at temperatures above boiling.
I once ended up convincing my Mom into using the "cooking the inside" heuristic of a microwave in order to save an apple Charlotte that came out with uncooked dough in the center [2]. It took a few single-minute zaps to get it there, but it worked great.
[1] Well, of course, the whole, but it's the inside that's important for this exercise
[2] She was quite distraught because she'd never had that failure in the dozen-plus times she'd made the cake previously. Despite being a veteran of the semiconductor industry, she suspected herself first instead of the oven hardware, which it turned out to be.
That and water is very good at storing heat meaning that it stays skin blisteringly hot even after the rest of the food has cooled down to edible levels.
George Washington did not have wooden teeth. His dentures were made of gold, hippopotamus ivory, lead, animal teeth (including horse and donkey teeth),[160] and probably human teeth purchased from slaves.[161]
Surprised to see "purchased from" paired with "slaves." It shows that the way slaves were treated was more nuanced than I thought. (Perhaps out of guilt? Because it seems any slave owner had enough power over slaves to just take them if desired).
If slaves can't be trusted not to run away without constant supervision, they're not cheaper than just paying someone to do the work (unless one person can somehow supervise a large group of slaves). What keeps a slave from running away even if they have the opportunity is the risk of getting caught and punished. But if the slaves are always punished (e.g. by forcefully removing their teeth), the decision is suddenly in favor of running away and maybe evading punishment. So it is in the interest of the slave owner to mostly treat their slaves like normal workers and pay them. The benefit of ownership is just that slaves can't easily find another job, so they can be paid less than a free worker.
> While Microsoft Windows has a much larger number of viruses developed for it, this is a consequence of its extremely large market share
...and it's terrible security and it's still prevalent installation method of downloading random binaries off of the internet and then executing them with administrator permissions.
I was very surprised reading this because my school's textbook claimed that microwaves heat food using the resonant frequencies of water. This fact was drilled into our heads over the course of multiple tests. It's disappointing that millions of students every year still learn this incorrect explanation.