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Topic: Refrigerator Light Bulb (Read 27698 times) |
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william wu
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Refrigerator Light Bulb
« on: Mar 17th, 2003, 8:02am » |
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From an tech-interview ... I kid you not:
When you open your refrigerator, you can see a lit light bulb.
How would you prove that the light bulb turns off when the refrigerator door is closed?
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| « Last Edit: Mar 21st, 2003, 11:38am by william wu » |
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towr
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Re: Refrigerator Light Bulb
« Reply #1 on: Mar 17th, 2003, 9:54am » |
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go sit inside the refridgerator of course :p
use a camera/webcam
put someone else in the fridge, get the out before frozen
make it impossible for the refridgerator door to close (a very logical solution, think about it)
explain and clarify the causal path between the door opening/closing and the lightbulb being turned on/off
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aero_guy
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Re: Refrigerator Light Bulb
« Reply #2 on: Mar 17th, 2003, 9:58am » |
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I hesitated to write anything because it just looked so silly, but since someone of towr's stature semi-seriously answered I guess I can too.
Open the door to show the light is on. Turn the temperature setting to the max (so it sin't overly cold inside). After the lightbulb has warmed up a bit, close the frig. Wait a couple minutes, open the frig with the now cool lightbulb. (have to have the refrigeration setting low so you can show it just wasn't the frig cooling the bulb)
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Icarus
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Re: Refrigerator Light Bulb
« Reply #3 on: Mar 17th, 2003, 5:33pm » |
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Find the button that the door holds in when it is closed. Push the button in with your finger to see that, yes, it does indeed turn off the light. Notice that for the door to be closed, the button must be pushed in far enough to turn off the light.
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redPEPPER
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Re: Refrigerator Light Bulb
« Reply #4 on: Mar 21st, 2003, 5:29am » |
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drill a hole through the door
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cho
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Re: Refrigerator Light Bulb
« Reply #5 on: Mar 21st, 2003, 7:11am » |
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I'm sorry. None of you gets the job. Remember, you're applying for a Microsoft position. None of the given answers could be programmed into the next version of Windows. Therefore the correct answer is to invent a Windows-refrigerator, complete with wireless internet to automatically order more brie anytime you're running low. You would then check on the lightbulb status by clicking Tools/Options/Preferences/Diagnostics/Interior/Peripherals/Lightbulb/Adv anced, at which point you'd see that the Lightbulb Monitor is greyed out because you must first go to the Control Panel/Light Bulb/Administrator/Permission, type in your lightbulb password (which Microsoft will invalidate after you change the lightbulb twice). Then return to Tools/Options/Preferences/Diagnostics/Interior/Peripherals/Lightbulb/Adv anced/Lightbulb Monitor. You'll learn that Windows leaves the light on all the time by default. To turn it off you must locate the appropriate checkbox located somewhere in your toaster oven.
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Boody
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:)Re: Refrigerator Light Bulb
« Reply #6 on: Mar 21st, 2003, 7:23am » |
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Eternal question in fact.
in formal way:
> When you open your refrigerator, a light bulb turns on.
should say that the light is off before turn on. 
But we're not sure at which moment that the light bulb turn off, is it really when we close the door ? 
I think that we can ask the question
- light is on or light is off when the door is closed
to the Schrödinger's cat.
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william wu
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Re: :)Refrigerator Light Bulb
« Reply #7 on: Mar 21st, 2003, 11:40am » |
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on Mar 21st, 2003, 7:23am, Boody wrote:Eternal question in fact.
in formal way:
> When you open your refrigerator, a light bulb turns on.
should say that the light is off before turn on.
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Nice catch; my previous phrasing presumes that the bulb is off until you open the door. I've changed the phrasing to say that you merely see an on bulb upon opening the door.
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maryl
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Re: Refrigerator Light Bulb
« Reply #8 on: Mar 26th, 2003, 8:30am » |
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What if you stuck a mirror out of the bottom of the fridge, and watched it's reflection as you open and close the door?
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James Fingas
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Re: Refrigerator Light Bulb
« Reply #9 on: Mar 26th, 2003, 10:36am » |
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With most fridges, the light bulb turns off shortly before the door is completely closed. Just close it gradually and watch the crack (especially at night). You will see the light turn off.
But I know this is too easy an answer 
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BNC
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Re: Refrigerator Light Bulb
« Reply #10 on: Mar 27th, 2003, 3:47am » |
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on Mar 17th, 2003, 8:02am, william wu wrote:
...When you open your refrigerator, you can see a lit light bulb....
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My refrierator's bulb just burned out. So now, when I open my refrigerator, I do not see a lit light bulb. Hence the question is invalid 
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How about supercalifragilisticexpialidociouspuzzler [Towr, 2007]
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SWF
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Re: Refrigerator Light Bulb
« Reply #11 on: Mar 27th, 2003, 5:13pm » |
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BNC, if your bulb is burned out that is a good indication that a working bulb is on much of the time, and maybe it goes on when the door is shut (or you spend too much time with teh door open).
In mine the bulb is cool when the door is first opened, but heats to above room temperature in a just few seconds, so I assume it is off when shut.
Putting a running video camera inside would be practical to do and can be done with the door totally shut- no wires running out. Could also try to grow a plant inside that thrives in low temperatures. It would quickly get ill if it is kept in the dark.
Put a phosphorescent watch inside. After a while, with a dark kitchen, unplug the refrigerator, and look at the watch. If the phosphor is brightly glowing then the light was on inside.
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Icarus
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Re: Refrigerator Light Bulb
« Reply #12 on: Mar 27th, 2003, 5:19pm » |
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Call the "refrigerator psychic" and ask for a reading!
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Mr. GuestMan
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Re: Refrigerator Light Bulb
« Reply #13 on: Sep 23rd, 2003, 6:43am » |
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Of course the not so smarter, but perhaps ingenious solution would be to wire a copper wire to the socket, unplugging the lightbulb, closing the door and touching the wire to see if the wire is HOT.
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Sir Col
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Re: Refrigerator Light Bulb
« Reply #14 on: Sep 23rd, 2003, 7:59am » |
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1) Unplug the fridge, in a darkened room place photographic paper inside the fridge, and close the door. After a suitable length of time, remove the paper and examine for exposure.
2) Wire a buzzer to the light socket. Close the door. If the buzzer stops, we know the light goes off. Unless, of course, the fridge contains a rapid air evacuation device that creates an almost instantaneous vacuum when the door is closed.
3) Check the manual that came with the fridge: "Rather than run the risk of mechanical failure of the light operation switch found on most fridge doors, this refridgerator contains a unique internal illumination feature; the light is always on." 
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Grimbal
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Re: Refrigerator Light Bulb
« Reply #15 on: Apr 30th, 2004, 3:48pm » |
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Here is a philosophical question. Is a light still on when there is nobody to see it?
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Grimbal
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Re: Refrigerator Light Bulb
« Reply #16 on: Apr 30th, 2004, 3:49pm » |
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on Mar 17th, 2003, 9:54am, towr wrote:go sit inside the refridgerator of course :p
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And don't forget to take your lighter, or you won't see anything. 
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pedronunezmd
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Re: Refrigerator Light Bulb
« Reply #17 on: Jun 18th, 2004, 7:06am » |
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I hate to be picky, but everyone who has answered this question so far is wrong!
All of these solutions that have been proposed so far only prove that the lightbulb is off during the period of observation. For example, sitting inside the fridge and watching the bulb goes out means the bulb went out during that door closing, same with pushing the little button thingy, same with using a webcam, etc.
How do you know the rule for turning off the lightbulb isn't: when door closes, pick random number from 1 to 1 trillion, if the number = 34, then leave light on when door closes, otherwise turn light off?
The only way to prove that the lightbulb goes off when the door closes is to take the fridge apart and show the circuitry that controls "the door closing -> lightbulb turns off".
More specifically, it is actually not the closing of the door that turns the lightbulb off, what you are actually proving is that when the door closes in such a way that it pushes that little button down, then the lightbulb goes off. (If you whittled the button down to nothing, such that closing the fridge door did not result in the button being depressed, then closing the door does not cause the light to go off.)
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Grimbal
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Re: Refrigerator Light Bulb
« Reply #18 on: Jun 18th, 2004, 7:28am » |
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You are right. It simply is not true.
There are these huge refrigerators in the food processing industry where the light is just a switch near the door. Closing the door does not switch the light off. Then there are the refrigerators that have no light. Or those where the switch-off mechanism does not work. Closing the door still does not switch the light off.
So we should reformulate the problem as: "Given a refrigerator such that there is a light inside that is switched off when the door is closed, how can you prove that the light inside is switched off when the door is closed.". But then, it is obvious, isn't it?
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pedronunezmd
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Re: Refrigerator Light Bulb
« Reply #19 on: Jun 18th, 2004, 8:12am » |
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Well, I think the question is, "If you have one of those fancy state-of-the-art refridgerators where the lightbulb goes off when you shut the door, how would you prove to someone that that was the case, that the lightbulb did indeed go off?"
To a skeptic like me, just showing me one instance where the lightbulb went off when you shut the door would not convince me that everytime you shut the door, the lightbulb goes off. I wouldn't believe that you could afford such technology.
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DMaJ007
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Re: Refrigerator Light Bulb
« Reply #20 on: Jun 29th, 2004, 4:43pm » |
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The answer is simple. Take out the engineer schematics of the fridge to show the wiring and effects of the door button which controls the light, then simply show that physics causes the door to latch on to the fraim via magnets or some other device. Thus when the door is open, the only way the light could indeed turn on was through the button and the only way that, using a proper non burnt out lightbulb, the bulb would be kindled would be if the button was pushed.
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pedronunezmd
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Re: Refrigerator Light Bulb
« Reply #21 on: Jun 29th, 2004, 4:54pm » |
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on Jun 29th, 2004, 4:43pm, DMaJ007 wrote:| The answer is simple. Take out the engineer schematics of the fridge to show the wiring and effects of the door button which controls the light, then simply show that physics causes the door to latch on to the fraim via magnets or some other device. Thus when the door is open, the only way the light could indeed turn on was through the button and the only way that, using a proper non burnt out lightbulb, the bulb would be kindled would be if the button was pushed. |
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Nah, I still won't believe that the schematics were correct. You could just as easily have forged counterfit schematics or bought a forgery from a refridgerator-schematics blackmarket which are rampant in many parts of third world countries. You'll still have to show me the actual circuitry, sorry.
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Three Hands
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Re: Refrigerator Light Bulb
« Reply #22 on: Jul 1st, 2004, 3:35am » |
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Well, if you are being a true skeptic, then I couldn't successfully prove that the lightbulb exists in the first place, let alone what state the bulb is in while it is unobserved
However, I think this riddle is looking more for an argument that would show beyond reasonable doubt that the bulb turns off when you shut the refridgerator door, so many of the suggestions provided so far would be fine for this (in my opinion), although some of them may wish to repeat the demonstration a few times in order to make the probability of a fluke less likely.
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pedronunezmd
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Re: Refrigerator Light Bulb
« Reply #23 on: Jul 1st, 2004, 10:41am » |
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on Jul 1st, 2004, 3:35am, Three Hands wrote:| However, I think this riddle is looking more for an argument that would show beyond reasonable doubt that the bulb turns off when you shut the refridgerator door, so many of the suggestions provided so far would be fine for this (in my opinion), although some of them may wish to repeat the demonstration a few times in order to make the probability of a fluke less likely. |
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Oh, shoot, someone is taking my posts seriously? 
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Three Hands
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Re: Refrigerator Light Bulb
« Reply #24 on: Jul 2nd, 2004, 4:56am » |
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Well, I am doing Philosophy, after all. The appeal to questioning what we actually know is one which comes up quite a bit for philosophers, and the basic answer is that we know very little, but tend to believe quite a lot, and most of these beliefs (that what we see is real, that the future will resemble the past in terms of causality, etc.) appear to have caused us little harm thus far, and would probably cause us a lot of harm if actively disbelieved.
Oh, and in response to Grimbal, Bishop Berkeley's answer would be that the bulb is being constantly observed by God, and so not only continues to exist, but also remains in the state that it should
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