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Thursday, December 3, 1998 Published at 21:46 GMT


Professor spills secret of the dripping teapot

The theory blames low pressure at the tip of the spout

The mystery of why tea dribbles down a pot's spout, rather than pouring cleanly into the cup, has been solved by an expert in fluid flow.

The BBC's Mike Liggins puts the British teapot to the test
Such spillage is a natural phenomenon - and not the fault of poor spout design - according to Professor Jean-Marc Vanden-Broeck, of the University of East Anglia.

The Belgian academic, who for 20 years has specialised in calculating fluid flows, spent a month studying "the teapot effect".

[ image: Professor Jean-Marc Vanden-Broeck: An expert in fluid flow for 20 years]
Professor Jean-Marc Vanden-Broeck: An expert in fluid flow for 20 years
"Don't worry, it's not your fault - that's what I'd say to people who are worried about their pots," Professor Vanden-Broeck said.

"Tea, or any other fluid, dribbles down any design or shape of pot or pouring apparatus.

"I have discovered that the pressure in the fluid underneath the spout is very low. The fluid therefore gets pushed on to the spout by natural atmospheric pressure."

The findings are the second scientific breakthrough in the world of tea. Last week scientists from Bristol University discovered the perfect way to dunk biscuits without them disintegrating into the cup.

[ image: Millions of cups of tea are poured every hour]
Millions of cups of tea are poured every hour
Professor Vanden-Broeck has worked out a formula, contained in two pages of computer data, that could predict where and in what shape the dribble would come.

But he poured scorn on suggestions that his research was trivial.

He said: "My work on the teapot effect is an important mathematical investigation that can be applied generally to all fluid movement.

"I think it's important responsibility of applied mathematicians to make our work relevant to the practical world."

A UEA spokesman said: "Professor Vanden-Broeck's work does have some very serious applications for situations when liquid hits a hard surface, such as the design of a ship's front."

[ image: Drinking spilt tea in this way is most undignified]
Drinking spilt tea in this way is most undignified
Professor Vanden-Broeck's revelations received a warm greeting from the tea industry.

Sarah Ward, from the Tea Council, said: "We welcome the professor's findings, and if he finds a cure for dribbling teapots that would really be fantastic".

A spokeswoman for china teapot makers Wedgewood said: "The art of pouring still tea still rests with the pourer, no matter how fine the teapot is".

The Department for Trade and Industry also praised Prof Vanden-Broeck's work.

A spokesman said: "If it is true, we congratulate the professor on his discovery. I am sure tea drinkers around the land tonight owe him a vote of thanks."

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