Win a holiday to Sweden with A molecule's eye view of water

Visitors to the Royal Society's Summer Science Exhibition stand the chance of winning a holiday for two to the ICEHOTEL in Swedish Lapland, courtesty of the exhibit A molecule's eye view of water.

Play their free iPhone/iPod game Waterfall at their exhibit to stand the chance of winning the holiday for two to the ICEHOTEL, dinner at belowzero in London, or an Ice-Watch.

Download the Waterfall game at home, and you could win an Ice-Watch.

Waterfall is a simple, fun and addictive puzzle game developed for the exhibit, based on the nano-scale structure of ice crystals. You can download it free from the Apple Store.

The competition for visitors to the exhibit and players at home is open until the exhibition closes on Sunday at 8.30pm. See their terms and conditions for full details.