This is probably a really basic question, but I realized I'm not sure what the answer is. What is the mechanism for light heating an object? Are photons always absorbed by electrons (if they are absorbed at all)? Maybe this will help explain my question: People often say that infrared light generally heats an object, whereas UV can actually break bonds/ionize atoms. But does infrared do essentially the same thing (excite electrons to higher energies, but below the ionization energy) or does it do something else entirely?