The Hydrogen Bond Theory

A 2013 study from Nanyang Technological University proposed the most elegant explanation yet. As water heats, the molecules drift apart and stretch the hydrogen bonds that link them.

In the 2013 hydrogen-bond model, heating stretches the hydrogen bonds between water molecules while the covalent O-H bonds shrink and release stored energy. The model suggests that this release gives hot water an extra cooling route. The debate over which mechanism dominates, however, is far from over.