Instead of taking the temperature of a representative sample of customers, firms must identify the few special customers who innovate.

ECONOMIST: The future of innovation

Therefore, a puff of water appearing on a Martian sample cooked to that temperature would imply that it is partly made of clay.

MSN: New Mars rover hunts for life by 'cooking' rocks

Last year Dr Smith and Alanson Sample, a researcher at the University of Washington in Seattle, powered a small humidity and temperature sensor using nothing more than the energy gleaned from a television station 4.1km (2.5 miles) away.

ECONOMIST: Monitor