As a chemist, I have some philosophical doubts about explanation of facts.
In Bertrand Russell's book 'History of Western Philosophy' he says that leading-to scientific knowledge is the 'why', not in a sense of purpose but in a sense of causation. So, to explain facts, in science, we use the cause. In this sense, it should be enough to say "A produces B" as explanation of facts. Theories are powerful tools for that purpose. A theory, as quantum theory, is accepted only if it has been validated with experience. After that, its results can be used as explanations.
Taken into account the last paragraph, I wonder what are the ways in which we explain by using the cause. In the macroscopic world, as said, it is enough to say 'A produce B'. But then there are theories. The explanation is called reductionist if tends to explain the whole as the interaction of the parts. In this way, biology tends to chemistry and it tends to particle physics. There is also a kind of explanation in the same layer. For example, thermodynamics explain the macroscopic world in term of constants, and so on.
An example in chemistry
If we ask why liquid water evaporates from a glass in the sun, the answer can be made in terms of thermodynamics or statistical thermodynamics; same layer or a lower one, respectively.
I suppose there are more ways of explanation of facts, and want to read a complete answer or an essay about this subject.
Any interesting reference on this problem?