ENIGMA: Why put a glass rod in coffee cup?

  • Thread starter Elana
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  • #26
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Something to note, if it works with other drinks and a spoon, it has nothing to do with strength of the drink.
 
  • #27
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true...

could molecules be attracted to the metal or glass? could the hydrogen stick to it or go up to the surface?
 
  • #28
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Glass is inert in comparison to a metal spoon so not really.
 
  • #29
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then keep the oxygen in the liquid, contain its freshness and taste?
 
  • #30
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then keep the oxygen in the liquid, contain its freshness and taste?
How? Glass won't react with the contents, metal would but not that quickly.
 
  • #32
turbo
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then keep the oxygen in the liquid, contain its freshness and taste?
You're over-thinking this, IMO. He puts a glass stirring-rod in his coffee so everybody will know that it is his coffee. In your first post you said that a spoon would do as well - I think that is supposition on your part and not part of the problem that he posed to you.
 
  • #33
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You're over-thinking this, IMO. He puts a glass stirring-rod in his coffee so everybody will know that it is his coffee. In your first post you said that a spoon would do as well - I think that is supposition on your part and not part of the problem that he posed to you.
Agreed, despite all the solutions I'm still stuck with mine, for the reason I pointed out in response to oldfart above.
 
  • #34
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He puts a glass rod in his coffee and tells everyone to guess why he does, offers money to the one that comes up with the right, scientific answer.

A metal spoon would do as well, I quote.

It's not for stirring, nor identifying his cup.
 
  • #36
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He puts a glass rod in his coffee and tells everyone to guess why he does, offers money to the one that comes up with the right, scientific answer.

A metal spoon would do as well, I quote.

It's not for stirring, nor identifying his cup.
So the whole "works with other drinks" is your own creation? Or is it only with coffee?
 
  • #37
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no, he said with other drinks too.

but whatever
 
  • #38
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Given that glass won't react, it can only be a visual thing (given he's taken heat out of the equation).

There's nothing else it can do.

EDIT: I suppose it could keep a rough track of the level of the drink.
 
  • #39
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there's this thing that if you put some kind of conductor in a cup while pouring hot liquid inside it will not blow due to temperature changes. say if the cup is cold.
 
  • #40
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there's this thing that if you put some kind of conductor in a cup while pouring hot liquid inside it will not blow due to temperature changes. say if the cup is cold.
This would be the same basis for putting milk into the cup first, the difference in specific heat values of the milk and glass help prevent the warm drink splitting the china cup.

However, if this works with other beverages (not warm) this isn't true.

And, glass isn't a particularly good conductor of heat.
 
  • #41
turbo
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Still, it is a method of identifying his drink, IMO. A spoon would work as well, but not ANY spoon. A fancy monogrammed spoon would work very well, but it's not quite as elegant as using a glass stirring rod from the lab.
 
  • #42
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Still, it is a method of identifying his drink, IMO. A spoon would work as well, but not ANY spoon. A fancy monogrammed spoon would work very well, but it's not quite as elegant as using a glass stirring rod from the lab.
And a spoon certainly doesn't have the 'fear factor' that a glass rod from the lab has!

It sounds to me like he's looking for someone to be word perfect on it and rejecting even remotely close guesses.

Tell your teacher that the greatest minds in physics :uhh: have joined forces and haven't got a clue, and have proclaimed it a load of psuedo-rubbish. :wink:
 
  • #43
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it's most likely only for pouring the drink into the cup. if the fluid is poured down the spoon or glass rod it will prevent spilling.
 
  • #44
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it's most likely only for pouring the drink into the cup. if the fluid is poured down the spoon or glass rod it will prevent spilling.
Wouldn't that make its use fairly self-evident to the students though?
 
  • #45
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Wouldn't that make its use fairly self-evident to the students though?
not if he doesn't pour it in front of them?
 
  • #46
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glass has a higher heat capacity than metal (I think?) so its used to cool his drink without adding milk. Yes, it would work with a metal spoon but maybe not as well.
 
  • #47
glass has a higher heat capacity than metal (I think?) so its used to cool his drink without adding milk. Yes, it would work with a metal spoon but maybe not as well.
The teacher has rejected any heat related issues. What mathplease has suggested is also quite plausible (considering that all other options have been so far inconsistent with the question or the incorrect answer). This is an interesting thread by the way. I would like to wait for an answer... Though this might turn out to be one of those sly tricks played by old timers (you know, the teacher may just say that there is no particular reason and that all this was just to bring a new perspective of thinking to the students)
 
  • #48
dlgoff
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Maybe he doesn't want the acids in the coffee to react with a spoon. Hence glass?
 
  • #49
Integral
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Maybe he just likes hearing the questions which it generates.
 
  • #50
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Maybe he doesn't want the acids in the coffee to react with a spoon. Hence glass?
But he said it also works with a spoon.
Maybe he just likes hearing the questions which it generates.
It sounds good, making people come up with 'scientific' solutions to the problem he has posed but I'm not sure if it is useful in the long wrong. Especially if he's offering a cash prize to the person who correctly works it out when there's nothing to solve.

Personally, I'm sticking with my previous idea (cup marker in some form), but I think the OP needs to word it very specifically - he ain't gonna give up that cash unless it's spot on - call them on a technicality if you will.

If it's nothing to do with heat and not a visual marker in any way, what purpose could it serve?
 

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