ENIGMA: Why put a glass rod in coffee cup?

  • Thread starter Elana
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  • #1
Elana
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Hello All,

One of my science teachers puts a glass rod in his coffee, but he won't tell us why... I was wondering if there was a physic/chemistry related explanation to this.

He said that the effect did not occur before when he didn't put it in. Adding the glass rod ''solved the problem''.

It would apparently work with a spoon and with other drinks then coffee also.

Would anyone know what this glass rod does??

Thank-you!
 

Answers and Replies

  • #3
Elana
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Not really... he just leaves it in there all the time.
 
  • #4
symbolipoint
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Too simply the glass rod is for stirring to help dissolve sugar or sweetener.

The glass rod could also be used for decanting if he made his coffee using ground coffee in a beaker with hot water and transferred the brew from the beaker to the drinking cup.
 
  • #5
Elana
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That's what I thought too but he said that wasn't it...

Though when I asked if it was to somewhat keep the liquid's heat (even thought it wouldn't make a big difference...) he said it wasn't it either.

Would it be possible for the rod to keep the molecules in movement?
 
  • #6
Brandon_R
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He probably just uses it to stir the coffee when no one is looking.

Side Note - Aren't science teachers just the best :)
 
  • #7
JaredJames
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He probably just uses it to stir the coffee when no one is looking.

Aside from stirring, I see no other use for the rod either.
Side Note - Aren't science teachers just the best :)

I'd agree for the most part, but we had a few who were complete prats.

Our physics teacher was more interested in his electronic whiteboard than in teaching. At least half of every lesson was him messing with it.
 
  • #8
JaredJames
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A quick Google noted a few results mentioning "Glass Rod Coffee Filters" if you're interested. You might want to check that out - mentioned it can affect the taste.
 
  • #9
Elana
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If it would be as easy as stiring (which we did ask) I would not put this up :P
 
  • #10
JaredJames
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If it would be as easy as stiring (which we did ask) I would not put this up :P

I do hope that when you get the solution it isn't stiring....

Regardless, have you noted my final reply.
 
  • #11
Elana
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I already know the solution isn't stiring.

And yes i've seen it, it could be possible... however he did say that the effect could be reproduced using a spoon with any other drink, so i don't think it's for filtering
 
  • #12
JaredJames
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Well next to acting as a radiator to help bleed off heat (which would work with a spoon in any other beverage), there really isn't anything else that comes to mind.
 
  • #13
Elana
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This is going to bug me for the rest of my days... :P

Same here... my teacher said it was chemistry/physics related... And that it wasn't about the heat of the liquid... So i'm clueless...
 
  • #14
JaredJames
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So a stationary glass rod (or spoon), in a cup of drink, that is nothing to do with stirring or temperature.

You got me. Sounds like a load of rubbish and/or pseudo-science.

That's like saying "I keep a pencil behind my ear at all times. It has nothing to do with providing easy access to a scribbling stick, transportation of said implement or holding my hair back. Why do I do it?"
 
  • #15
Elana
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I know....

well, no wonder he offers money to the one who figures the answer out
 
  • #16
pallidin
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.

You got me. Sounds like a load of rubbish and/or pseudo-science.

Yeah, maybe it used to be his crack pipe :biggrin:
 
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  • #17
JaredJames
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Just something that popped into my head:

I'd say it marks the cup as his so no one else drinks it - or that it's his current, warm beverage.

Think about it. By leaving the glass rod in at all times it marks the cup as his. Solving the problem of other people using it.

Heck, you could even take it as far to say that by leaving the glass rod in there, it looks like an experiment (being a science teacher) and that people would be scared to drink it. (Or that it's been used in an experiment so not suitable to drink out of). There's your chemistry/physics answer.

My physics teacher used to leave his lunch in the "do not use" fridge that was supposed to be for experiments. It stopped other people touching it.

Start thinking outside the box.
 
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  • #18
Brandon_R
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Yeah, i think that rod may be more for aesthetic beauty than functionality. I mean can you just picture this A mad scientist in his lab with lighting flashing in the background, pressing the button to bring life to the dead holding a coffee cup with a glass rod in it!! Devious.
 
  • #19
Elana
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Trust me I've thought about everything outside the box... the box is sealed with multiples layers and I have to open it! :P

And that Mad Scientist image is pretty funny :P
 
  • #20
JaredJames
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Trust me I've thought about everything outside the box... the box is sealed with multiples layers and I have to open it! :P

And that Mad Scientist image is pretty funny :P

So you've asked about what I mentioned above?
 
  • #21
turbo
Gold Member
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Just something that popped into my head:

I'd say it marks the cup as his so no one else drinks it - or that it's his current, warm beverage.

Think about it. By leaving the glass rod in at all times it marks the cup as his. Solving the problem of other people using it.

Heck, you could even take it as far to say that by leaving the glass rod in there, it looks like an experiment (being a science teacher) and that people would be scared to drink it. (Or that it's been used in an experiment so not suitable to drink out of). There's your chemistry/physics answer.

My physics teacher used to leave his lunch in the "do not use" fridge that was supposed to be for experiments. It stopped other people touching it.

Start thinking outside the box.
Good thinking jnj! Nobody else in the teachers' lounge is going to grab his coffee cup.
 
  • #22
Oldfart
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I'm guessing that it has something to do with cappilary action or surface tension. Might the glass rod actually be a tube of very small inner diameter? Perhaps the quality of the coffee can be indicated by the amount of rise of coffee in the tube, or by the contact angle of the coffee to the rod. My second guess is that the strength of the coffee is indicated by how far below the surface the rod remains visable. Or maybe it's an index of refraction thing (how much the rod appears to be "bent" could be proportional to the strength of the coffee).
 
  • #23
JaredJames
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My second guess is that the strength of the coffee is indicated by how far below the surface the rod remains visable.

Ooh, now that I like.

The only reason I'm sticking to my idea above is because it was stated it was left in the glass all the time - implying not only when liquid is in it.
 
  • #24
Elana
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  • #25
Elana
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I'm guessing that it has something to do with cappilary action or surface tension. Might the glass rod actually be a tube of very small inner diameter? Perhaps the quality of the coffee can be indicated by the amount of rise of coffee in the tube, or by the contact angle of the coffee to the rod. My second guess is that the strength of the coffee is indicated by how far below the surface the rod remains visable. Or maybe it's an index of refraction thing (how much the rod appears to be "bent" could be proportional to the strength of the coffee).

The tube does not have an inner diameter, but that would be something worth experimenting!

That's the kind of answer i'm looking for :P I'll propose those ideas! thanks!
 
  • #26
JaredJames
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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
Elana
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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
JaredJames
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Glass is inert in comparison to a metal spoon so not really.
 
  • #29
Elana
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then keep the oxygen in the liquid, contain its freshness and taste?
 
  • #30
JaredJames
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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
Gold Member
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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
JaredJames
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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
Elana
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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.
 

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