[an error occurred while processing this directive]
BBC News
watch One-Minute World News
Last Updated: Monday, 22 December, 2003, 19:36 GMT
Antibubbles made in Belgian beer
Antibubbles, IOP/Stephane Dorbolo
Antibubbles are the reverse of normal bubbles
Scientists have been able to understand the unusual phenomenon of antibubbles - the rare, reverse form of normal bubbles - by forming them in beer.

Typical bubbles are thin films of liquid enclosing pockets of air, but antibubbles are a thin film of air which encloses pockets of liquid.

Belgian researchers said on Monday they could make antibubbles appear in a many different liquids - not just alcohol.

Dr Stephane Dorbolo details his team's work in the New Journal of Physics.

Beer or dishwater

The scientists observed that antibubbles could be created by pouring a liquid containing a surfactant (a substance such as soap that alters the nature of a surface) on to an identical liquid.

They form because a thin film of air is sometimes pulled down along with the liquid itself.

Beer is very similar to dishwashing liquid and contains surfactants which are needed to produce antibubbles
Dr Stephane Dorbolo, University of Liege
This air film then separates the two liquids with the same composition and is therefore called an antibubble - since a real bubble is a liquid film separating two regions of air.

Out of curiosity, the researchers also attempted to create antibubbles in Belgium's most famous export - beer.

Dr Stephane Dorbolo, from the University of Liege, said: "We tried to create them in beer for fun, and didn't think it would be possible, but were amazed when we managed to create giant antibubbles which lasted for almost two minutes.

"You can't create antibubbles in pure water, alcohol or oil. But beer is a special case because it is very similar to dishwashing liquid and contains surfactants which are needed to produce antibubbles."

The scientists found that when antibubbles burst they took on a shape they nicknamed "the jellyfish", which moved slowly and then faded until they disappeared altogether.

Antibubbles have been recognised for a century but the physics that underlies their existence is still being investigated.

Homemade antibubbles

  1. Take some water in a clear bowl or tank
  2. Fill it to the very brim with dishwashing liquid (water with a few squeezes of washing-up liquid in it)
  3. Keep some of this liquid back in a beaker or jug Very gently pour the liquid from the beaker onto the surface of the bowl
  4. Watch beneath the surface as you pour and vary the speed at which you pour
  5. If you find the right speed, you might see antibubbles form as the stream of water descends beneath the surface
  6. You can now watch these antibubbles move and sink downwards and they will eventually burst.



SEE ALSO:
Chuck out the Chardonnay
02 Apr 98  |  Food Show
Double bubble is no trouble
21 Mar 00  |  Science/Nature
Brewer cheers beer's bumper summer
09 Sep 03  |  Business


RELATED INTERNET LINKS:
The BBC is not responsible for the content of external internet sites


PRODUCTS AND SERVICES

News Front Page | Africa | Americas | Asia-Pacific | Europe | Middle East | South Asia
UK | Business | Entertainment | Science/Nature | Technology | Health
Have Your Say | In Pictures | Week at a Glance | Country Profiles | In Depth | Programmes
Americas Africa Europe Middle East South Asia Asia Pacific