Heavy water is not just heavier. Swapping each H in H2O with a D — hydrogen’s isotope deuterium — changes many of water’s properties. Heavy water is poisonous, and its freezing point is 4° Celsius, instead of 0°. Those differences may reveal that quantum effects rule in ordinary water, researchers have now found.
The results, reported in an upcoming Physical Review Letters, could shed light on quantum theory’s relevance for ordinary water, which is the medium for most of the action inside living cells. The work could also help explain some controversial findings on how biological molecules behave in water.
Quantum objects, such as atomic nuclei, have properties of both waves and particles. Quantum effects aren’t usually manifest to the naked eye, but in this case they may be responsible for some of water’s unusual features. “The quantum effect in water is abundantly obvious,” says Alan Soper of the Rutherford Appleton Laboratory in Didcot, England.