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I think the social friction from getting all of this right/wrong really damages inquisitive minds. The visceral negative response you get from, "Wait, I don't

by nomel 2y ago

I think the social friction from getting all of this right/wrong really damages inquisitive minds. The visceral negative response you get from, "Wait, I don't think that's right, it's more complicated than that", helps prevent speaking up the next time, unless you have an inherently disagreeable personality (which I cherish working with). I see it all the time with kids. They'll see some fundamental truth that takes a sideways perspective to see, and be told they're wrong, hacking off an interesting way of perceiving the world. It's unfortunate, but it's also something most adults are bad at, including myself. And, I very often microwave my spoons, forks, even metal bowls, without them heating up at all. But I also have a basic understanding of resonance, absorption, insulation, apertures, and the wavelengths involved. I don't do it at work, because it's not worth the effort responding to "you're going to break the microwave", even if you show them that the food is hot and the fork is cool. That said, I wouldn't melt metal in an expensive microwave. The metal has poor absorption relative to the magnetron antenna itself, so both will heat. I wouldn't be surprised if the antenna is also glowing a bit (at least early on)!

Dylan16807 2y ago
> That said, I wouldn't melt metal in an expensive microwave. The metal has poor absorption relative to the magnetron antenna itself, so both will heat. I wouldn't be surprised if the antenna is also glowing a bit (at least early on)! You don't make the metal absorb the microwaves. Either your crucible or the inner lining of your insulator will be designed to do the absorbing.
- krisoft 2y ago
  > the inner lining of your insulator will be designed to do the absorbing. That is exactly the case with our setup.
- nomel 2y ago
  Ah, well I'm guilty! The videos I saw, in the past, were just a ball of fairly fine wire on a plate. This was probably 20 years ago, when I was looking into melting black beach sand in the microwave. For a rant about that, it turned out pretty neat. I put the beach sand in a thin layer on a dinner plate that was a half wavelength above the bottom of the microwave, turntable removed. The beach sand would start to melt where the standing waves were, but then quickly grow into a wire structure, with the growth of the tips driven by where absorption would be maximized, allowing the thing to heat more, and grow more. I tried to model the resulting "antenna", but none of the open source tools at the time could handle the complexity.
  - tomtom1337 2y ago
    This was a wonderful little read, thank you!
    - Obscurity4340 2y ago
      As was this, thankyu sir
Gormo 2y ago
I've come to realize that pretty much every general rule we have is only ever really true within a bounded context defined by a certain set of assumptions, and models that we think are universally applicable seem so simply because we can't (yet) look beyond their context of applicability. Even scientific models that we regard as describing fundamental laws of nature will stop describing reality accurately once you hit extreme conditions -- Newtonian physics breaks once you're dealing with relativistic contexts, for example. The human mind has tendency to generalize its heuristics, and hold certain rules to be either absolutely true or absolutely untrue, which unfortunately hobbles our ability to use our rationality to its fullest potential. People will often dismiss an entire model as being universally "false" as soon as they see a single data point that it doesn't work for, and then try to formulate a new model that's still trying to encompass everything, everywhere. Maybe we'd do better to interpret falsifying data points as helping to map the outer boundaries of the model's applicability, and formulate multiple models, each optimized for different contexts, and each regarded as valid within its bounds.
vel0city 2y ago
I still remember lots of microwaves coming with metal racks so you could stack multiple things in them. Sometimes they still do come with them. https://www.youtube.com/watch?v=14oO_saaM9Q https://www.youtube.com/watch?v=14oO_saaM9Q

by nomel 2y ago

Dylan16807 2y ago

> That said, I wouldn't melt metal in an expensive microwave. The metal has poor absorption relative to the magnetron antenna itself, so both will heat. I wouldn't be surprised if the antenna is also glowing a bit (at least early on)! You don't make the metal absorb the microwaves. Either your crucible or the inner lining of your insulator will be designed to do the absorbing.

krisoft 2y ago
> the inner lining of your insulator will be designed to do the absorbing. That is exactly the case with our setup.
nomel 2y ago
Ah, well I'm guilty! The videos I saw, in the past, were just a ball of fairly fine wire on a plate. This was probably 20 years ago, when I was looking into melting black beach sand in the microwave. For a rant about that, it turned out pretty neat. I put the beach sand in a thin layer on a dinner plate that was a half wavelength above the bottom of the microwave, turntable removed. The beach sand would start to melt where the standing waves were, but then quickly grow into a wire structure, with the growth of the tips driven by where absorption would be maximized, allowing the thing to heat more, and grow more. I tried to model the resulting "antenna", but none of the open source tools at the time could handle the complexity.
- tomtom1337 2y ago
  This was a wonderful little read, thank you!
  - Obscurity4340 2y ago
    As was this, thankyu sir

Gormo 2y ago

I've come to realize that pretty much every general rule we have is only ever really true within a bounded context defined by a certain set of assumptions, and models that we think are universally applicable seem so simply because we can't (yet) look beyond their context of applicability. Even scientific models that we regard as describing fundamental laws of nature will stop describing reality accurately once you hit extreme conditions -- Newtonian physics breaks once you're dealing with relativistic contexts, for example. The human mind has tendency to generalize its heuristics, and hold certain rules to be either absolutely true or absolutely untrue, which unfortunately hobbles our ability to use our rationality to its fullest potential. People will often dismiss an entire model as being universally "false" as soon as they see a single data point that it doesn't work for, and then try to formulate a new model that's still trying to encompass everything, everywhere. Maybe we'd do better to interpret falsifying data points as helping to map the outer boundaries of the model's applicability, and formulate multiple models, each optimized for different contexts, and each regarded as valid within its bounds.

vel0city 2y ago

I still remember lots of microwaves coming with metal racks so you could stack multiple things in them. Sometimes they still do come with them. https://www.youtube.com/watch?v=14oO_saaM9Q https://www.youtube.com/watch?v=14oO_saaM9Q