Electric current in Coca cola Menthos

[thinhnghiem]

Few years ago, we have known about the phenomenon that Coca cola is overflow severely when a piece of Menthos candy is put inside.

 

I replicate this experiment, with a multimeter is used to measure the current. With my surprise, the needle vibrates to show that an electric current is generated.

 

Could anyone repeat my experiment to find out that if I am wrong or not

 

Thank you

[Schrödinger's hat]

Few years ago, we have known about the phenomenon that Coca cola is overflow severely when a piece of Menthos candy is put inside.

 

I replicate this experiment, with a multimeter is used to measure the current. With my surprise, the needle vibrates to show that an electric current is generated.

 

Could anyone repeat my experiment to find out that if I am wrong or not

 

Thank you

 

Interesting, could be the conductors along with the acid creating a cell. As the chemical reaction happens, the ph/conductivity changes.

How much current did you measure? Did it alternate or just change in magnitude?

[thinhnghiem]

I don't know if there is acid in content of Coke or not.

 

My measurement result is about 20 or 30 mA. It changes in magnitude.

 

I am appreciate if you can share your time to replicate my experiment to check if I am wrong or not. It's so easy

[Schrödinger's hat]

I don't know if there is acid in content of Coke or not.

 

The dissolved CO2 forms an acid (carbonic acid, I think) in the water.

[mississippichem]

The dissolved CO2 forms an acid (carbonic acid, I think) in the water.

 

I second that. Carbon dioxide in water gives carbonic acid, a weak acid.

[Schrödinger's hat]

There's also some kind of acid in the flavouring, come to think of it. I recall reading something about a study on excessive (litres a day) diet soda intake and damage to bones, can't remember the details or conclusion.

Edited February 28, 2012 by Schrödinger's hat

[Fuzzwood]

It contains a shitload of phosphoric acid, so you bet it's acidic []

[ewmon]

Water saturated with CO₂ reduces the pH to ~5.8, but as Fuzzwood said, Coca-cola has phosphoric acid, which apparently brings the pH down to about the ~3 that I remember stated for cola-type sodas.

 

I think you'd need to be using dissimilar electrodes to make a battery, but it's standard that a meter's electrodes are identical metals, not dissimilar. Then there's placement/connections. If one electrode was in the cola and the other was clamped onto the Menthos, there might be some sort of electron flow generated between the two, but Menthos electrode is destroyed quickly.

 

When I heard about an electric current found in a cola-Menthos solution, I wondered how such a current could be measured if not by purposely making some sort of battery, and it still puzzles me.

[John Cuthber]

The electrodes probably start off identical, but once one gets a bit scratched it's not the same any more. That would be my first guess. But it is possible to set up a cell where the only difference between the electrodes is the concentration of one of the components.

In a freshly opened bottle of pop the CO2 concentration, and hence the H+ ion concentration, will differ from one part of the solution to another.

http://en.wikipedia.org/wiki/Concentration_cell

[thinhnghiem]

Another question:

 

My experiment results in Dc current, not DC voltage. I also use DC volt function to measure, and nothing happens

[ewmon]

What amount of current are you measuring?

[John Cuthber]

What amount of current are you measuring?

I presume it's the 20 to 30 mA he referred to earlier.