It lost energy because of conservation of energy, okay? Eventually, enough of these atoms will attack or hit the surface of the water that it will lose most of its energy, and this will cool it down, okay? And that's why convection can only occur in the presence of molecules. And conduction requires physical contact. The third and final type of energy transfer that occurs due to heat is called radiation. Radiation is the energy transfer that occurs due to the presence of electromagnetic waves, okay?