[Elana]

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!

[nj_bartel]

Stirring?

[Elana]

We did propose these things, which were all denied:

- stiring
- containing the liquid's heat
- filtering the coffee

But he said the effect could be done with a spoon in any other liquid...

Would it be possible for the rod to keep the molecules in movement? 

[jeffrey.struss]

How about cooling the liquid down more rapidly?

[cth]

That reminds me when I was student and we had to measure precisely the volume of a foamy liquid. I don't remember exactly what it was. But what I do remember:
- if you poor the liquid directly into the measuring devise, you get a lot of foam and it is very hard to do an accurate measure.
- if you let the liquid flow along a metallic road (it was a spatula) into the measuring devise, the amount of foam is significantly reduced. 

I don't know the mechanism behind this phenomenon. 

[Stepan]

That reminds me when I was student and we had to measure precisely the volume of a foamy liquid. I don't remember exactly what it was. But what I do remember:
- if you poor the liquid directly into the measuring devise, you get a lot of foam and it is very hard to do an accurate measure.
- if you let the liquid flow along a metallic road (it was a spatula) into the measuring devise, the amount of foam is significantly reduced. 

I don't know the mechanism behind this phenomenon. 

Surface tension between liquid and rod prevents formation of bubbles and reduces splashing of the liquid. Also, rod helps direct the flow of the liquid into narrow opening of a bottle or a funnel.

[Elana]

The foam's effect is interesting!

So pouring the liquid on the rod will reduce spashing, i'll propose that.