Night Cap Experiment: A Creamy Treat
By Mark Steer
Well, Christmas Day is drawing to a scientifically satisfying and gluttonous end. There’s just time for a quick nightcap before heading off to bed and dreams of turkey sandwiches. And how better to round off the day than with a tasty demonstration of alcohol-induced convection? Crack open the Tia Maria will you.What to do
- Get a wide-bottomed glass and pour yourself a healthy slug of Tia Maria. It might be worth testing to see if Kahlua works as well. And maybe dark rum…
- Pour some single cream (or you could try Baileys etc etc) gently into the glass so that it forms a very thin layer floating on top of the Tia Maria. This is done best using by pouring the drink carefully over the back of a spoon.
- Watch beautiful, intricate and constantly changing patterns emerge through the cream as the two liquids mix slightly.
- Carrying on watching as you pour yourself a large glass of Scotch.
- Enjoy.
What’s happened
You’re watching convection in action, but special convection because this isn’t heat-driven; like a lot of things in life, it’s fuelled by alcohol instead.
Alcohol slowly diffuses through the cream and when it reaches the surface is decreases the surface tension of the cream in that area. The cream is therefore attracted towards the areas of higher surface tension and pulls away, leaving a slight void to be filled by more Tia Maria which further decreases the surface tension. The whole process therefore becomes a constantly moving mishmash of cream and booze. Baileys will work, but not as well because it also contains alcohol.
Watch this video to see it in action (caution: not for the easily patronised):
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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: Rie Shoji
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