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2:40 (leancrew.com)
154 points by thisisblurry on June 20, 2012 | hide | past | web | favorite | 99 comments

Interesting comment:

"A proper microwave designer would know that the best position to get something out of the microwave is how it was put in, and take care that regardless of microwaving time, the turntable would always stop in the position it started."

At my ex-company, I've always commented how well designed was microwave because it always end up in the same orientation as the start.

Turns out, it was just that it did a complete turnaround on a time segment (5 seconds) and it was easiest to input time in 5 second intervals.

Still, good, if not great design.

I would say it is great design.

Why? Because there is an also very important requirement: when the user wants to get his stuff out let him do it immediately: do not waste his time. This way they did not compromise this important requirement while gave a solution to the other problem as well.

But was that intentional design or just a happy accident and was that "feature" recoqnized as such and institutionalized?

Agreed, just didn't want to edit the post.

Funny! I often enter the time not divisible by 5. Say, the package says 4-5 minutes, I can press 444 to get to 4:44, it's easier.

(Well, maybe it is me who is funny, I don't know.)

That's exactly how our very old Sanyo microwave works. It turns off the power but keeps spinning until it reaches the initial position.


A later comment points out a microwave that does this (also the one ricardobeat mentioned):

»My 1990’s Sanyo Microwave has a “boomerang turntable”, meaning the turntable always returns to its starting point. It turns for a few seconds after the oven stops, until a micro-switch, driven by a cam on the shaft, is tripped.

The period or revolution happens to be exactly 12 seconds. (Has a synchronous motor?) I know this because any multiple of 12 seconds means the turntable stops immediately.«

Jack Donaghy is commenting on tech blogs now.

Ceremonies and rituals are like stored procedures for humans. I wonder how much of the ritual contained in the major world religions today are fossilized remains of some guy just figuring out how to avoid some disease or make daily life a touch easier and having it catch on. "And thou shalt set thy dial for 2:40, not 2:35 unless thou then proceedeth to 2:40... 2:45 is right out."

"Civilization advances by extending the number of important operations which we can perform without thinking about them" -- Alfred North Whitehead

I have been interested in the subject ever since I read the part of Code Complete dealing with the notion of abstraction. If everytime you woke you had to think about the fact that a door is a bunch of atoms that together form different materials but together some of it being the doorknob you'd never be able to leave your bedroom. It ties closely with the notion of affordance

A teacher told me that the reason for the banning of pork in the Quran and the Bible is to prevent some diseases. Straigth up banning pork for health reason solved the problem. It's probably some kind of myth.

That reminds me of the story of the woman who was taught to cook a roast by cutting off the ends. One day, her husband asks why do you throw away perfectly good cuts of meat, and she says her mother taught her that way. Questioning it, they go to the mother who says that's how grandma taught me. They go to grandma who says that's how great-grandma taught her. They go to great-grandma, who laughs and said "We couldn't afford a big pan so I had to cut the ends to fit it into the pan I had."

Well, reading the Old Testament sometimes feels like reading "health and safety manual". Like the rules about what's considered clean and not, how to quarantine people that were sick, but now seem to be healthy, etc.

I seem to remember that water in some agricultural regions of Indonesia was allocated based on a certain religious ritual called Subak. Apparently, although it appears to be an inefficient system, villages which experimented with supposedly more efficient, Western systems ended up harming their ecosystem and saw lower yields on subsequent years. Here's the Wikipedia article, though it doesn't have much:


See also the space shuttle / horse's ass story: http://www.snopes.com/history/american/gauge.asp

Just like the ritual cat described here: http://www.katinkahesselink.net/tibet/zen.html

My microwave use hack isn't turntable or cup position related. It's that I round to the least number of unique buttons to press and still get near the needed cook time. For example, 33 sec for half a minute, not 30 sec. 99s for a minute and a half. Over the years I must have saved nearly as much time as it's taken me to make this post.

Same here, I always do 60 instead of 1:00 or 90 instead of 1:30 to save an extra button press.

I do this _and_ the handle synchronization thing (with some angle tolerance to get the single button time). This discussion is making me feel a bit OCD.

Most microwaves let you keep pushing the start button to add 30 seconds to the timer.

This guy needs my 1990's vintage Sanyo microwave with "boomerang turntable", meaning the turntable always stops in the same position. This is done with a micro-switch/cam combination on the shaft.

If you are really impatient, and don't want to wait for the turntable to finish moving, the period of revolution is 12 seconds. Programming in multiples of 12s means the item is ready to remove as soon as the beeper goes off.

Assuming modern microwaves have a microchip on which computation can be done, and an electric motor of controllable speed, couldn't the microwave calculate the speed required for the specified time to end at the right angle, with no delay?

Too many people (like me) take things out of the microwave a second or two early as to avoid the obnoxious beep. :)

You're assuming too much.

Appliance manufacturers go for the cheapest parts possible that still perform reliably under the warranty period. The motor driving that turntable is not a precision stepper or brushless motor with variable microprocessor speed control. It's a cheap A/C motor (perhaps with a drive belt for torque) that's switched to line current by a 30-cent mechanical relay. You can tell it's A/C when the turntable starts in a random direction each time it's energized.

Most microwaves I've seen just alternate between directions. It's not random.

It is random. You need a larger sample size.

There is no need to put an expensive polarity-reversal circuit (with mechanical or electronic memory) in the assembly just to alternate the turntable direction. The cooking effect is the same.

Based on my observations, I'd say it actually does alternate. My theory is that the motor speed is slow enough and consistent enough, as is the friction, that the motor consistently overshoots by half a pole when it stops. Thus, it moves in the opposite direction when turned back on. If it was moving faster, it might well be random. What's the chances of it displaying bifurcation then chaos? :-)

Given that the period of my oven is bang on 12 seconds, averaged over many revolutions, I think it's probably a synchronous motor.

Interesting observation on the random direction, I'd always wondered why that was.

The other thing to remember is that in the 1990s a microwave oven cost several hundred dollars at least. Now you can pick one up for fifty bucks, possibly forty. Losing extraneous features like "boomerang turntable" is presumably part of how the manufacturers managed to respond to the downwards price pressure.

No, he needs a cup with multiple handles. It's cheaper and they work in all kinds of microwaves :o)

Or, he could just heat the water in the thermal mug! (assuming it's non-metallic)

It's funny how americans boil water in microwaves, while the rest of the world does it in kettles. There was a discussion on reddit about it. I didn't realize it, but apparently it has to do with the fact that most americans rarely drink tea, but rather prefer coffee from coffee machines and so they don't need kettles. Personally, I can't imagine how one can boil water in a microwave, it sounds ridiculous (in a good way, no offense), but these little differences fascinate me.

The first time I traveled to Australia I found an electric tea kettle in my room, and it was one of those ah-ha moments. It was a perfectly obvious invention, and yet, the idea had never before crossed my mind. As an American, you boil water the hard way, or in a microwave.

You can find them in stores here, but they're not popular. I've told several people about them, and they were just as delightfully surprised as I was.

As an American, it is totally bizarre to me that many of my fellow citizens are unaware of electric tea kettles.

The problem is that electric kettles in America are slow as fuck, which I assume is due to the 110V power supply.

Go somewhere with 240V and two things happen: (a) you're far more likely to die of electrocution in your own house and (b) you can get a decent tea kettle.

A 3kw heating element is a 3kw heating element at whatever voltage it operates, so I suspect that there may be a limit on the current that domestic appliances can use in US kitchens.

At 110v you would be looking at 27 Amps which may be a little high. I had not thought this one through before, thanks.

American outlets are 15 or 20 Amps, AFAIK.

In case grandparent is too elliptical for some readers --

The maximum current determines how thick the wires have to be. Since power (ability to heat or do other work in one unit of time) == current * voltage, doubling the voltage doubles the amount of power a wire of a given thickness can deliver.

Well done, I should have emphasised the principal.

Looks like the maximum power that a US kettle can produce is 110 * 20 = 2200 watts, so will take about 3000 * 2200 = 1.36 or 36% longer than an EU kettle to boil.

Microwaves make more sense in that scenario

Microwaves have their own problems - they can superheat water without boiling it, which will then explode in a fury of scalding foam as soon as you jostle it.

They're also frequently mounted overhead, where it's more dangerous to retrieve a mug or big Pyrex cup. Contrast that with the kettle which has that little flap over the spout and is spill resistant.

I'm American and I use my microwave regularly, but not for boiling water (when I make coffee using my Aeropress or French press, not tea - and don't get me started about drip coffee). For that, I use a kettle on my gas range. It's not much longer, and I can ask if anyone else wants coffee and boil more water easily.

The time it takes to boil the water is about the same amount of time it takes for me to grind my coffee beans and set up the Aeropress, so it works out.

It's not just an 'old world' vs. 'new world' thing either. I'm Canadian, and this is the first time I've heard of someone boiling water for tea in a microwave. I guess it's something the Loyalists took with them :)

> I can't imagine how one can boil water in a microwave, it sounds ridiculous (in a good way, no offense)

So curious... what sounds so ridiculous about it? It seems so natural and obvious for me...

That's funny.

I find using a microwave to boil water so... strange and unnatural. I'm not sure why, but its just odd. That's what a kettle is for!

Why buy another appliance when a microwave does the job perfectly?

Non-American here, I always use a microwave if I'm just making one cup.

The author should try drinking loose leaf teas instead. I'm sure the gains of switching away from tea bags (which often contain whatever can be swept up off of a tea factory floor) are worth touching a hot handle.

Loose leaf teas are much harder to steep, and if you steep them wrong, you end up with a rancid bitter flavor (for lots of higher quality teas).

To quote a song: "You could not feel sadness if you've never tasted joy" - perhaps, if he's content with his tea bags, we can let him drink his tea bags. Since switching, I can tell you first hand, that I can no longer drink tea bags, or even poorly steeped teas without cringing. I sound like an asshole, I know.

There's a great quote about not refining your tastes as it narrows your world but instead continuing to explore the availability of the world around you. It was either Feynman or Ryan Dahl. =p

That being said, I love me my loose tea leaves, but it's just a different product then bagged tea, one hasn't ruined the other.

It's not that hard with a bit of electronics: Japanese homes usually have big electric kettles with temperature control. Green tea, as an example, needs 80C I think.

Japan in general is a great example for optimizing people's daily lives without compromising on quality. There are many of such rituals to explore that are very specific to that country.

Right, but I'm assuming that he's used to over-steeping because he is removing the teabag already. Teabags can make astringent tea, too.

It is a somewhat interesting philosophical question of whether or not it's worth it to try something better if it might affect what you already enjoy.

Or eliminate the pyrex measuring cup and just buy an electric kettle...

Quite. I sold my microwave a few months ago and can't remember why I ever thought I needed one.

Warming up yesterday's leftovers?

I'm one of those people without a microwave. Instead, I have a toaster oven. For warming up leftovers, the toaster oven or stove does just fine, and most of the time it turns out better than the microwave, as it doesn't get mushy.

This is the second apartment I've lived in without a microwave, and I think I've missed it all of twice. Once, when I wanted some popcorn, and a second time when I was in a hurry to heat something up.

A frying pan can do that too.

You would reheat lasagna in a frying pan?

No, but a casserole in a slow oven will do a much better job reheating lasagna than a microwave will.

Don't get me wrong, if it was just for my lunch, I'd use the microwave, but if I was plating something for family dinner, I'd use the oven.

Why an electric kettle and not a regular one? It seems like an electric kettle is just another single-use appliance taking up counter space.

Plus, I mean, look at this kettle and tell me you don't want it: http://www.etsy.com/listing/97984435/retro-80s-seibel-bubble...

I'm as appreciative of the "multitaskers only" kitchen mentality as anyone, but an electric kettle is a "single use appliance" in much the same manner as a Pyrex measuring cup is: it's a pretty important "single use".

A distinct advantage of electric kettles over stovetop kettles is precise temperature control. High-end loose-leaf white and green tea wants 70c-82c water; Aeropress coffee wants 80c-90c.

Speed is obviously another benefit. Good electric kettles are significantly faster than stovetop kettles.

Also, electric kettles take up counter space, but stovetop kettles take up space on your cooktop. Space is more constrained on the cooktop; you probably only have 4 burners, and on my stove, if the front two burners have skillets on them, it's awfully hard to maneuver with the rear burners.

Also, I hate the ergonomics of cutesy round tea kettles, and, obviously, that's a tea kettle: most electric kettles hold more water.

I want to clarify that I'm not looking to get into a holy war about tea kettles o_O.

I didn't realize electric kettles could control water temperature. Which one do you have? I've always just boiled water, and then let the temperature fall to where I want it, even when using an electric kettle.

Also, for me, the fact that the regular kettle is on the stovetop is actually better, because that space is almost never in use (only during cooking), and when I do need, I can temporarily shift the kettle elsewhere. My counter space, on the other hand, is always at a premium (I only have 2 squares.)

The one in our office and the one at my house both have temperature settings, but I'm not sure of the brand on either.

interestingly, here in Australia an electric kettle is one of the required basics of any kitchen. Even the cheapest nastiest hotel room will contain a toaster and an electric kettle

I don't want it. I want a cordless one with a dock and a zillion-watt element that can boil a litre of water in forty seconds.

He wouldn't even need to touch a hot handle, everything else can be kept the same. the only difference would be a little required filling of a tea ball before he started and emptying the tea ball after he is done. an additional 10-15 seconds for tea that is streets ahead.

I must ask, have you watched Community? Otherwise, they have successfully coined the phrase "streets ahead" to the point were people actually are using it seriously, and that would be cool.

"Streets ahead" has been an idiom in England for as long as I can remember (as a quick Google for the phrase suggests).

I think the story is that it was an idiom used in England and the show runner for community heard it and thought it was stupid so he incorporated it into Pierce's character.

You do realize that's an urban legend?

It's not entirely untrue to say that teabags are "swept off the floor", though it may be misleading. Typically, ALL tea is sorted on the factory floor. http://www.discoveringtea.com/2011/06/21/in-amgoorie-the-fac... However, it is true that the tea in most teabags is "dust" or "fannings": very small broken pieces of tea leaves that remain after the higher grades are sorted out. https://en.wikipedia.org/wiki/Fannings

While a few companies like Mighty Leaf do offer higher quality, whole-leaf tea in bags (or rather, sachets), at that point you're paying as much as a 2x-3x premium over loose-leaf tea of comparable quality. For example, this tea from Adagio is about 16¢ per cup loose-leaf, but 40¢ per bag: http://www.adagio.com/black/ceylon_sonata.html

I'd suggest anyone who likes tea get a stainless steel mesh infuser (they're about $10) and go loose-leaf. It's worth it.

Not all teabags, but certainly some brands. Teabag quality has admittedly gotten better in recent years.

I think the method of heating water is orthogonal to the type of tea used.

He kinda lost me with the unfunny cartoon, the sugar but no milk, and the microwaving the water for your tea thing. For an alternative, and I think authoritative opinion, try Christopher Hitchens, here: http://www.guardian.co.uk/theguardian/2011/jan/03/christophe...

Also, Douglas Adams on a very similar subject:


So the best advice I can give to an American arriving in England is this: Go to Marks and Spencer and buy a packet of Earl Grey tea. Go back to where you’re staying and boil a kettle of water. While it is coming to the boil, open the sealed packet and sniff. Careful---you may feel a bit dizzy, but this is in fact perfectly legal. When the kettle has boiled, pour a little of it into a teapot, swirl it around, and tip it out again. Put a couple (or three, depending on the size of the pot) of tea bags into the pot. (If I was really trying to lead you into the paths of righteousness, I would tell you to use free leaves rather than bags, but let’s just take this in easy stages.) Bring the kettle back up to the boil, and then pour the boiling water as quickly as you can into the pot. Let is stand for two or three minutes, and then pour it into a cup.

I don't trust the idea of microwaving water for tea, because microwaved water will probably be sub boiling temperature.

actually microwaved water will frequently be above boiling--microwaving lets the water remain still enough for it to get superheated. when you disturb it (with a teabag, spoon, etc.) it will start bubbling wildly (and quite possibly give you a nasty scald)

And by "frequently" you mean "almost never, cuz I've been trying to get it to happen for years and it damn well doesn't"

It depends on what you have the water in. A very smooth-sided container with very pure water has few nucleation sites and so the water is much more likely to become superheated, while a beaten up mug and standard tap water is less likely to superheat without boiling.

happens to my tea all the time--i don't know if it's actually superheated in the sense of being >212, but it sits perfectly still in the mug until i drop the bag in, at which point it goes nuts with the bubbles.

If you feel like this guy and his pyrex-cup-microwaving ways are threatening your identity as an obsessive, over-optimizing nerd, you may wish to try making your coffee with chemistry gear like in breaking bad:



Microwaved tea! :S Required reading: http://onegoodmove.org/1gm/1gmarchive/2002/12/a_proper_cup_o...

(but in all seriousness interesting article about the problems of not critically addressing things that annoy you)

I don't think there's any physical difference between water boiled in a microwave vs in a pot (free radicals?).

Lighter teas (white, green, chamomile, etc) are best brewed at 70-80C, so that's not general advice :)

There isn't any difference, except often when people microwave water they don't get it all the way to boiling. With a kettle it's pretty obvious when your water is at boiling.

Be aware of superheating!

Well, don't worry unless you have a really smooth cup and going for 5-10 minutes or more...

I've tried to superheat water in my microwave and never managed it.

A problem I didn't know existed. Will be fixing it next time I turn the damn thing on.

the design thing that i notice about most microwaves is that some of them let you just punch in a time and hit start, while others make you hit "cook" first.

i find this to be an excellent example of (failing at) optimizing for the common case--probably >99% of the interactions people have with microwaves are pure timed-cook-at-100%-power, and requiring an extra button press to enter that mode is silly.

Some let you just press the "add minute" button and it immediately starts cooking on a one-minute timer. Want to cook for more than a minute? Keep pressing that add-minute button while it's cooking.

yes, i love that one! now that's good common-case optimization.

first world problem

Yeah. I'm still not sure how i should respond to such problems. My first reaction is to judge them as irrelevant and that a wise person would valuate such things as misguided. On the other hand, every man (and woman) in fact is living in his or her own world (or worlds). And it should be fair to make your world as nice as possible.

Not sure if one can expect mankind to extend its horizons to the whole world or universe as it really is. The older I get, the more I think of us just being animals at all. This "look beyond your own nose" thing is maybe not so realistic/real for our species, as nice it sounds in theory.

Reminds me of a comic http://questionablecontent.net/view.php?comic=2202

My predominant reaction as well

Interesting fact. Or urban legend (who can tell the difference nowadays?)

What blocks microwaves is thin metal plate in the door. With holes so you can see inside.

It's a Faraday cage. And if you read specs in the manual, it' says the percentage that it blocks "for sure" to match some regulation. Hint, never close to 100%

And there's a percentage of radiation that goes out, and fry the inpatient that keeps it's face there

What blocks the radiation (at ~2.4GHz) is the metal all around the cooking cavity. The holes aren't actually a problem: as a rule of thumb we don't worry about shield leakage once the maximum dimension of a hole (diameter, in the case of a round hole) is less than 1/2 wavelength. 2.4GHz has a wavelength of 12.5 cm. Leakage does not happen through those holes.

(It does happen through the gap between the door and the rest of the microwave, but there's some neat design work to keep it from getting too bad.)

Of course it leaks, though. It leaks so much that when I was working on sensitive RF receivers, I could see when microwaves were turned on for lunch hour in other parts of the building. It's the leakage that makes it interfere with wifi. Don't worry though, you absorb more RF energy through the wifi in your devices and through your cell phone.

Wasn't implying it leaks by the holes :) just that nobody (i didn't use to) think it was a sheet of metal there only

Interesting fact: a relative of mine has a pacemaker, and can feel leaky microwaves (I guess there's some voltage induced on the edges of the device, and some nerves pick it up). It turns out that almost all old microwaves (older than 5 years) are leaky, and she has to leave the room. Most new microwaves are fine.

Of course there's a percentage of radiation that gets out, that's how you can see your food spinning round.

I'm fairly sure the holes are sized such that only certain wavelengths can leave, but that could be nonsense.

It's not nonsense

Of course, you can block/scatter visible light that way, but it's awfully difficult (since the holes would be tiny)

I stopped reading after I saw that he's putting sugar in his tea.

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