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comment by Devac
Devac  ·  2727 days ago  ·  link  ·    ·  parent  ·  post: Snap, Crackle, Kale: The Science Of Why Veggies Spark In The Microwave : The Salt : NPR

I'm un-deleting this, but I want to say one thing: If it sounds like I was on methamphetamine while writing incoherent stream of consciousness… it's because I probably started having fever already and crashed shortly afterwards. Just bare in mind that while it's about problem solving and complexity, I feel a bit confused about it while reading it now.

    It's even less good to know that scientists have some theories but ultimately aren't exactly sure why.

I'll argue this point. Aside of being of same mind as oyster on that one, I would like to have a try at showing how solving problems escalates. See, the main obstacles regarding solving complex problems are:

- Amount of people with the know-how and willingness/time (both dependant on money)

- Coordinating a group of experts and making them communicate efficiently (hard but underestimated task!)

- Incredibly steep rise in difficulty the more detailed your hypothesis/model gets

Here's a good way to show what I mean. Let's keep to electromagnetism and say that I am interested in the uniform, conducting, ideal disk in the external (constant) electric field and what I want to find is the behaviour of induced currents inside the disk and the charge distribution. If I were to add "the disk is neutrally charged before the electric field appeared" it's a problem that most high school students should be able of answering. However, real-life problem is going to be a coin in time-dependant electromagnetic field (microwave).

Now, let's assume that this is not a disk but something with actual width. Basically a coin-shaped ideal conductor without charge in a constant electric field. That's a bit more problematic, but doable by a freshman student. In a time-dependant electric field that is a fairly simple function (something like E(t) = E * sin(wt)) it's still doable on this level.

Getting more complex: we want to know about a real coin after all. Would there be a difference to solution if we don't polish coins? Intuition says yes and I can actually solve this problem for a uniform layer of dirt that can be assumed as having negligible depth. However, having to deal with polished and unpolished coins basically splits our research path.

If the coin is polished, and assuming above idealisation, let's now notice that depending on the surroundings of the coin we can find shapes of the box where anything interesting can't even occur. Why? Because we know that EM wave can be reflected, and if the surroundings can also reflect it… we get various interference relations. So we take the 'box' with coin inside and ask questions about positioning the coin. Size of the coin very likely matters (related to wavelength), but not as much as direction of electromagnetic wave!

For unpolished coin you have all of the above with additional questions regarding type of dirt, fraction of surface that was polished (hard!), and determining if unpolished case would be the same as polished coin with diminished reflection. It isn't, because depending on what the dirt is (let's be specifically-idealistic) and say that it's a uniform layer of oxide of the metal used for making the coin.

This problem is likely for a graduate student in physics. And we are still talking about fairly simplistic model of a coin without any features… in the vacuum! I can tell you that's it not a problem until you will start considering the surroundings to be either non-linear for EM wave and probably some other factors. Air, even with water vapour, is going to have a lesser effect than having the coin submerged in water.

Here is a place where a preliminary experiment would be in order. Coins made of pure nickel, copper and some copper-nickel alloy. Various sizes, all polished. Dirtying them done by applying various oxidising chemicals for set time duration (to allow building thicker, but uniform, layers that we can actually look-up in metallurgy tables). Boxes of various sizes and shapes. Now we can have a fairly lengthy experiment montage that ends with theorists being given a lot of data to coordinate the efforts in the direction set by intermediate experiment.

Of course this is a gross oversimplification on my part. We already know how oxides influence internal currents, why certain wavelengths would produce much stronger result etc. But it's a good way to show that something as simple as a coin in a microwave problem is really complex after adding more factors. This problem was at some point an undertaking that likely could conclude with someone getting a doctorate afterwards.

Now the problem mentioned at the beginning would make it worth to apply a group of specialists and research budget to solve this problem in detail… or maybe use them for slightly more pressing problems. ;)





jadedog  ·  2725 days ago  ·  link  ·  

    Now the problem mentioned at the beginning would make it worth to apply a group of specialists and research budget to solve this problem in detail… or maybe use them for slightly more pressing problems. ;)

I have no doubt that the problem is complex and that it might take a lot of resource to solve.

My comment was from the consumer's viewpoint that it's not that helpful to know that kale might explode in the microwave but not know when. The only solution to be safe is not to microwave it.

As a current analogy, the Samsung Galaxy Note 7 is apparently catching fire and exploding in some cases. It's not really that helpful for people to know that their Note 7 might explode but not know if it will for sure or when. The only solution is to not use any of them, regardless if that particular one may not explode. It's too much of a chance to take. From the scientist's point of view, I have no doubt that it's an interesting and complex problem. It just doesn't solve the consumer's issue.

Devac  ·  2725 days ago  ·  link  ·  

True. But knowing why something happens would allow engineers prevent such mistakes in the future. I know that consumer only should care about the finished product, but it's important for them to understand that even most scrupulous QA and testing can't catch everything.

Here is the problem: let's assume that some fraction of semiconducting elements inside the phone were made from a faulty silicon crystal. Because it has some mechanical impurity it offers an increased resistance but the phone performs OK and passes checks. Unaccounted for this flaw heat disperses into the battery and you get an explosion. That's a sound theory, but even simulating it on a computer would require quite a lot of work to pin-point the most likely components to carry the fault. And this designer should put his inquisitive prowess to landing people on Mars rather than doing smartphone QA.

Just in case, I don't defend people who made this mistake. That's a terrible issue, fact that it's of unknown cause and depends purely on chance for what we know is even worse. But if a boob like me can think off of five or six possible hypotheses (and even more for kale)… imagine how many possibilities and explanations could make an engineer who actually knows this stuff. Finding a reason for any of these consumer product faults would basically need a research team. I can only hope that a proposal titled "Let's find a way to avoid exploding phones to avoid lawsuits, bad PR and harming our clients" would not have many problems with getting a budget.

jadedog  ·  2724 days ago  ·  link  ·  

    And this designer should put his inquisitive prowess to landing people on Mars rather than doing smartphone QA.

I lost you right here. Are you saying that scientists should only work on projects based on some kind of hierarchy of importance? Who gets to decide the level of importance?

Devac  ·  2724 days ago  ·  link  ·  

    Who gets to decide the level of importance?

Objectively? I don't know or even consider myself as someone who can answer that. Subjectively? Read below.

    Are you saying that scientists should only work on projects based on some kind of hierarchy of importance?

I don't know if I would call it importance, but there are problems with higher stakes. This also can vary per person. For the sake of argument, let's say that mankind's survival would be my most pressing goal. Stakes are high, as without some way to perform exodus and colonise other worlds, our whole existence could be wiped-out easily. If this would be my view of things, a phone or microwave harming someone would barely register as far as humanity is concerned.

That's hardly my view and I would rather veer away from anything involving ethics, but to me there is nothing prohibiting existence of some scale of importance. As I have said before, I don't consider myself an authority. My gut feeling is simply "hard problems don't have to carry much significance, but it's worth to try and solve them if possible".