Saturday, 20 September 2008

Carbonated Capers

After a delicious home-cooked breakfast, PJ and I set off through the bush towards a mineral water spring about 45 minutes away. It was a beautiful spring day and we wore backpacks containing a small gas stove, coffee, cups and a stove-top coffee percolator. 

Something went wrong: the coffee rose to the top but it was cold. Maybe because we used carbonated water, we're not sure. We stood around the spring and drank cups and cups of the delicious water, then things soon deteriorated transpired to us taking lots of photos and video clips of each other spitting the water out again.


ToneMasterTone said...

I've been thinking about this carbonated water problem and I think I have a solution to the mystery.

Normally what happens is that the water you put in the lowest compartment gets heated and some of the water gets gaseous. Gas takes up more space than water, which then makes things more cramped in the lower compartment and increases the pressure. Nothing likes being cramped, so the water defies gravity and moves up and through the ground coffee to find some space for itself in the upper compartment. Thusly, you have your coffee.

With carbonated water, it takes a lot less heat to release gas from the water. If you take a bottle of coke, all you need to do is shake it up a little and the carbon is released from the beverage and you can feel the bottle become stiff because of the increased pressure inside.

So, with the carbonated water in the bottom compartment, gas gets released at a much lower temperature. This means that the pressure builds up at a much lower temperature in the bottom compartment, so when the carbonated water seeks more spacious surrounds and defies gravity, it reaches the upper compartment at a concomitantly lower temperature.

Isn't physics wonderful?

Meg said...

Isn't physics wonderful? yes!!

and so too is your easy to understand explanation.

thank you!