Why does hot water freeze faster than cold water?
It's a question that has perplexed scientists for centuries and now the Royal Society of Chemistry is offering £1000 to whoever can come up with the best explanation for what is referred to as the The Mpemba Effect.
Judges will be looking for an outside-the-box submission that is creative and eye-catching.
The deadline for submissions is July 30.
Submissions should be made through www.hermes2012.org/ice. The answers will be reviewed by a panel of scientists and their decision will be final.