Getting Going Experiment: Champagne
By Mark Steer
No matter how slowly you pour champagne into a glass it’s going to froth up and there’s nothing worse than having to ungraciously chug back half a glass of champagne because it’s about to froth over the edge... well there are some things worse, but few as ungracious.However, there are ways you can avoid the trauma. You probably won’t want to do them with your best bubbly though, use the kids’ Coke instead.
What to do
- Get four champagne glasses and smear oil all around the inside of three of them.
- Add a healthy pinch of dust to one of the oily glasses.
- Add a teaspoon of sugar to another.
- Steal a bottle of coke from some over-excited children (or if you’re feeling flush use champagne,but I might never speak to you again).
- Pour some coke into each of the glasses in turn.
- Watch as you produce super froth in the oil+sugar glass, normal froth in the clean glass and the oil+dust glass and virtually no froth in the 'just oil' glass.
- Throw away your nasty concoctions and get down to some serious supping.
What’s happened
In fizzy drinks, gas is kept in solution by high pressure. When the bottle is opened, however, the pressure drops and the gas can start contemplating bubbling out - but it has another problem to overcome before it can do so. When a bubble starts to form it is very tiny and so the gas inside the bubble is under very high pressure. At high pressures gases dissolve in liquids, so our bubble re-dissolves into the drink as soon as it starts to form.
Bubbles can usually only form around small particles or irregularities in the surface of the glass or bottle which are hydrophobic – they push the water molecules away. In these areas the baby bubbles have a chance to grow to a big enough size so that the pressure inside them decreases to a point where they don’t re-dissolve.
When you poured the fizzy drink into the normal glass, small dents, dimples and dust particles in the glass gave the dissolved gas plenty of scope to form bubbles and froth up all over the place. However, when you smoothed the irregularities over with a coating of oil then there were many fewer places left for bubbles to form, so no frothiness.
By adding the dust and the sugar you are replacing the dips and dents that the oil has covered over. In the case of the sugar you are more than just replacing the irregularities, you’re creating a veritable bubble-making utopia. Hence an explosion of frothiness that’s very hard to get out of the carpet.
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This experiment has been adapted from Mick O'Hare's excellent book How to Fossilise your Hamster see more at www.newscientist.com/hamster.
How about trying one of our other top tens:
This experiment has been adapted from Mick O'Hare's excellent book How to Fossilise your Hamster see more at www.newscientist.com/hamster.
How about trying one of our other top tens:- Top Ten Crazy Xmas Gifts
- Top Ten Geek Holidays
- Top Ten Stupid Science Studies
- Top Ten Work-related Ills
- Top Ten Killer Vegetables
- Top Ten Weird Drinks
- Top Ten Grim Parasites
- Top Ten Things Science Hasn't Explained
Hub image: Michiel Pruijssers
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