ENIGMA: Why put a glass rod in coffee cup?

[Elana]

http://makegoodcoffee.com/coffee-talk/coffee-chemistry-from-an-expert/

would this work with a small glass rod too?

 

[turbo]

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.

 

[JaredJames]

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.

 

[Elana]

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.

 

[JaredJames]

http://makegoodcoffee.com/coffee-talk/coffee-chemistry-from-an-expert/

would this work with a small glass rod too?

No, did you read it? It's about storing coffee by ensuring as little moisture as possible. Not applicable here and certainly not with other beverages and spoons.

 

[JaredJames]

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?

 

[Elana]

no, he said with other drinks too.

but whatever

 

[JaredJames]

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.

 

[raam86]

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.

 

[JaredJames]

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.

 

[turbo]

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.

 

[JaredJames]

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 have joined forces and haven't got a clue, and have proclaimed it a load of psuedo-rubbish.

 

[mathplease]

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.

 

[JaredJames]

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?

 

[mathplease]

Wouldn't that make its use fairly self-evident to the students though?

not if he doesn't pour it in front of them?

 

[Gobil]

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.

 

[mishrashubham]

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)

 

[dlgoff]

Maybe he doesn't want the acids in the coffee to react with a spoon. Hence glass?

 

[Integral]

Maybe he just likes hearing the questions which it generates.

 

[JaredJames]

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 going to 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?

 

[torquil]

Maybe it reduces wave motion on the fluid surface, leading to less spillage as he walks around with the cup?

You mentioned that he said it also works with a spoon, but I haven't really noticed much difference when walking around with a cup with/without a spoon in it. But perhaps there is a small difference that he feels is significant.

 

[Fish4Fun]

Perhaps the glass rod is used to propagate sound waves. Once the glass rod is placed in the cup and the "prize" is offered, how long will the students continue to talk about it? What is the dampening affect of rejection? How far will the sound carry? Will the sound cause secondary wave motion (internet traffic)...

Oooooh, a swing and a miss :-) But it is as valid as anything else so far, LOL.

Fish

 

[jazon48]

I agree with Torquil (Post 51). It's a baffle. It tends to suppress waves when you walk around and thus reduces accidental spillage.

I do the same with a spoon and have done so for decades.

If it doesn't seem to make a difference when you try it for your self, perhaps you have a steadier hand than me or the science teacher.

Regards
jason

 

[jack action]

Putting an object in a liquid raises the fluid level which has two effects:

1. With the http://en.wikipedia.org/wiki/Buoyancy" , it makes the object immersed in the liquid feels lighter (which could «solve the problem» if he taught that the glass rod was too heavy to hold)
2. It increases the http://en.wikipedia.org/wiki/Hydrostatics#Hydrostatic_pressure" at the bottom of the cup (although I don't see which «problem is solved»)

 

[JaredJames]

Putting an object in a liquid raises the fluid level which has two effects:

With the http://en.wikipedia.org/wiki/Buoyancy" , it makes the object immersed in the liquid feels lighter (which could «solve the problem» if he taught that the glass rod was too heavy to hold)

So the glass rod is too heavy to hold, but he can hold the glass rod and the glass of drink it is in?

 

[turbo]

So the glass rod is too heavy to hold, but he can hold the glass rod and the glass of drink it is in?

A bad differential mass problem. :)

 

[JaredJames]

A bad differential mass problem. :)

"Mum, instead of rockets needing all that fuel to get them into space, why don't they just put them in a big glass of water and make them lighter? Silly NASA, and they call themselves rocket scientists!"

 

[jack action]

So the glass rod is too heavy to hold, but he can hold the glass rod and the glass of drink it is in?

I was thinking that the cup is resting on a table. So when he holds his glass rod in the coffee (say, when he's stirring), it feels lighter than when he's holding it in the air.

 

[Antiphon]

You all have it wrong. I do the same thing with a glass rod in my coffee cup.

The answer to the mystery is that it's a medical order by his physician.

For years I would drink coffee stirring it with a spoon. After a time I developed an increasingly sharp pain, usually in the left eye but sometimes in the right. I went to my doctor who listened very carefully to my problem. After a few minutes of thinking about it, he said "take the spoon out of the cup." I did and the pain was gone! I now use a glass rod to stirr my coffee but since it's glass and very hard to see I always remove it before taking a sip.

 

[JaredJames]

For years I would drink coffee stirring it with a spoon. After a time I developed an increasingly sharp pain, usually in the left eye but sometimes in the right. I went to my doctor who listened very carefully to my problem. After a few minutes of thinking about it, he said "take the spoon out of the cup." I did and the pain was gone! I now use a glass rod to stirr my coffee but since it's glass and very hard to see I always remove it before taking a sip.

And the name of the medical condition is? Perhaps a source to back it up?

My initial thoughts were medical, but then I was curious whether or not a metal spoon would react enough to cause problems.

Regardless, the effect the glass rod has can be replicated by a spoon, so even if what you claim is true it doesn't fit the conditions of the problem.