ENIGMA: Why put a glass rod in coffee cup?

[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.

 

[Antiphon]

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.

Sure. My source is "1001 cocktail party jokes" in softcover. I forget the author and publisher.

 

[JaredJames]

Oh poo. Completely missed that one, only read down as far as "medical related".

 

[ZamboniDriver]

A stirring rod is a glass rod, typically about 6 inches to 1 foot long and 1/8 to 1/4 inch in diameter that can be used to stir liquids in flasks or beakers.

You can also use a stirring rod to help pour liquids without spilling. Because of surface tension, liquids tend to run down an object. So if you hold a glass rod vertically, with one end in the opening of the beaker or flask you are pouring into, and then hold the top end of the glass rod against the rim beaker you are pouring out of, the liquid will run down the rod and not spill. Be careful... it might take a little practice to get the proper technique!

Sometimes, an attachment called a rubber policeman added to the end of the stirring rod. It is used to transfer residues of precipitates or solids from the inside or beakers, flasks or other glass surfaces. They are often made from rubber, but plastic ones can also be found.



Read more: http://wiki.answers.com/Q/What_is_a...policeman_and_how_are_they_used#ixzz1ByxwHPRJ

I hope this helps... an old bartender trick, might want to ask the old dog if he salts thee napkins whilst he drinks! I do!

 

[JaredJames]

Thanks for confirming to us what a glass rod is exactly, just in case someone was unsure of what a glass rod consisted of...

However, we've been down the road of using it to pour the liquid.

There's been no mention of any additional 'attachments', so I don't think they are part of the item / solution.

 

[ZamboniDriver]

The truth is that can be the only thing a spoon ans the glass rod be used for. The reason I put size down was in case it was somethng totally different. Besides try to pour a black and tan without a spoon... can't do it, some elderly people still use the glass rod to help pour hot liquids. Just a thought.

 

[JaredJames]

Well it's a nice try, just have to wait for the OP to return.

We've had a lot of "only possibilities" over the last day or so.

 

[skeleton]

The glass rod can also aid in pouring the liquid out of the container. The rod is removed, then laid over the top, across the diameter of the lip, and held skillfully with one finger. Then let the pouring liquid flow down the extending rod.

This helps to control the flow better, otherwise the liquid could break off and occasionally drip.

 

[JaredJames]

The glass rod can also aid in pouring the liquid out of the container. The rod is removed, then laid over the top, across the diameter of the lip, and held skillfully with one finger. Then let the pouring liquid flow down the extending rod.

This helps to control the flow better, otherwise the liquid could break off and occasionally drip.

Thank you for repeating this idea for the third time.

People, please read through before posting. We're getting a lot of recurring ideas.

 

[torquil]

To the OP: Has the solution been revealed? If so, I'd love to hear it.

 

[raam86]

Yep me too.

Does the coffee have milk on it? Maybe its to concentrate all the undissolved coffee around it?