The Ice Man Cometh: Erasto Mpemba flies into London

Erasto Mpemba, whose name was given to the mystery of why hot water freezes faster than cold water, will be in London this Thursday in a rare visit beyond his own country.

He has flown from Tanzania to join scientists at the Royal Society of Chemistry who will reveal the winner of a public competition launched last summer to find the best explanation of a puzzle that confounded Aristotle and defied everybody attempting to solve it since.

A team of postgraduate students based at Imperial College initially chose the hot-cold water topic as a challenge for handpicked young international researchers who were due to travel to Britain for Hermes 2012, a July summer school, sponsored by the Royal Society of Chemistry.

When, ahead of that event, the RSC asked the public for explanations of why hot water freezes faster than cold, emails and letters numbering 22,000 poured in from 122 countries, triggering a vigorous debate conducted via social media and the web.

So intense was the response that the RSC assigned a member of staff to manage the submissions, which came in a variety of forms, including a song composed by a competitor in New Zealand working into the early hours, breaking off to make telephone calls to the society's London offices.

The challenge even led to television presenter Jeremy Paxman losing his cool during Newsnight when an experiment with hot and cold water fizzled out because the BBC fridge had not been turned on by studio staff. 

Dr Robert Parker, chief executive of the RSC, said today: " We are very excited by the arrival and involvement of Mr Mpemba, who has stayed in the shadows in the 50 years since his discovery of the Effect when he was a teenage pupil in what was then Tanganyika.

"The manner in which he brought the phenomenon to the attention of Dr Denis Osborne, who was working in Tanganyika as a university physics lecturer, and the subsequent scientific paper they produced collaboratively, has developed a reputation and mystique of its own." 

Dr Parker added: "The persistence of the young Mpemba in pointing to the discovery he had made on his own and the resultant collaboration with Dr Osborne is a remarkable example of how a student and a teacher can work together and, in doing so, make a significant mark on the world. The spirit of constructive challenge and flexibility should always be a feature of the teaching and learning process."

Dr Izzie Radford, Mpemba project manager said: "This has presented the RSC with a very large logistical task since last summer, working with our postgraduate student partners at Imperial College and with Dr Osborne, who has remained a close friend to Mr Mpemba. With the support of an international panel of judges, and our colleagues at Imperial, we narrowed down the deluge of messages and submissions; tomorrow we will announce who has won the £1,000 prize which we offered in June."

Dr Denis Osborne, who will be at the award ceremony and who will host Mr Mpemba during his stay in London, said:  "It is terrific that Hermes and the Royal Society of Chemistry have drawn attention to this effect, now 50 years after it was first noticed by Mpemba.  Many have challenged and modified early attempts to explain it and the competition results have brought great advances, while demonstrating the enormous complexity of seemingly simple everyday situations.  

"Mpemba's story shows the dangers of an authoritarian, arrogant approach to science and how advances in what we know require open, inquisitive minds."   

The Mpemba award ceremony will be at The Chemistry Centre, Burlington House, Piccadilly, W1J 0BA at 10.30am on Thursday 10 January.