Today's news, tomorrow's lesson - ‘Supercooling’ phenomenon and the boy who inspired 50 year search for answers - 11 January

Today's news, tomorrow's lesson - 11 January

‘Supercooling’ phenomenon and the boy who inspired 50 year search for answers

By Kerra Maddern

Why does hot water freeze faster than cold water? This conundrum has puzzled scientists since it was discovered by an African pupil 50 years ago.

Erasto Mpemba was a 15-year-old teenager in Tanganyika, now Tanzania, when he noticed the paradox in 1963. And it has gone without explanation until now.

Scientists at the Royal Society of Chemistry organised a public competition to find the best explanation for what has become known as the Mpemba Effect. Yesterday (the 10th) they announced a winner of the £1,000 prize, chosen by an international panel of judges.

Having faced resistance to his discovery from his teachers, who simply said he was wrong, Mpemba turned to British scientist Dr Denis Osborne, who was working in Tanganyika at the time. They later worked together to produce a scientific paper on the effect and have remained close friends.

Mr Mpemba, now a retired wildlife park manager, has “stayed in the shadows” since then.

But scientists still celebrate him. “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,” Dr Robert Parker, chief executive of the RSC, said.

Nikola Bregovic, from the University of Zagreb in Croatia won the RSC competition, arguing that an explanation can be found in convection currents and a phenomenon called “supercooling”. However most scientists do not believe it is a definitive answer – the paradox goes on.

“Once again this small, simple molecule amazes and intrigues us with its magic,” Mr Bregovic said of water.

The RSC’s competition was launched in the summer and attracted over 22,000 applicants from 122 countries.


  • How many famous scientists can you think of?
  • Erasto Mpemba has become known for his discovery. How would you like to make your mark on the world?
  • Can you think of any phenomena which science does not yet seem able to explain?
  • Erasto Mpemba worked closely with Dr. Osborne to produce a scientific paper. Have you ever achieved something by working with another person?

Related resources

Heating and water cooling

  • Teach your class all about heating ice and the importance of measuring temperature with these PowerPoint aids.


  • Worksheets to help you explore heat loss and cooling through evaporation of water.

Famous scientist press release

  • These fact files celebrate the lives and achievements of some of history's most famous scientists.

Team work

  • Encourage pupils to work well together to complete these challenging activities.

Further news resources

First News front page

  • Help your pupils understand the features of the front page of a newspaper.

Write all about it

  • Get students creating their own news report with this step-by-step guide.

What is the News?

  • A sociological and media perspective on what makes an event 'newsworthy'.

On the box

  • Help pupils to write their own TV news broadcast with this handy PowerPoint.

Structuring stories

  • A scheme of work to help students structure news stories.

In the news this week

As much as half of all the food produced in the world each year ends up being thrown away, according to a new report.

Governments all over the world are increasingly concerned about the growing obesity epidemic, which is largely caused by unhealthy eating and sedentary lifestyles.

There could be as many as 17 billion planets like Earth in our galaxy, scientists have discovered, a number that dramatically increases how likely it is that aliens exist.

Sandy Hook shootings put US gun control debate centre-stage.

In the news archive index