Cause-and-effect vs. epiphenomena

Some people seem to confuse these concepts.

Cause-and-effect statement: My wife and I came to Rabinowitzes. The children were happy.

What I am saying is that children were happy as a result of my wife and me visiting them. One event led to another, with two events being completely separate.

Epiphenomenological statement: My wife and I helped out with the children. She played with the girls; I played with the boys.

In here, the second statement is the same as the first statement; it just provides more details. The two of us helping out with children and my wife playing with girls are not two separate events.

Now, let's see if we can give some examples of the two statements from science.

(1) The faster the molecules of air in the room move, the greater the room's temperature. 

(2) If you heat up the reaction, the beaker will explode.

In the first statement, I am not saying that change in temperature (and by that I mean an objective property of the room's air, not my perception) is caused by the change in molecules' velocity. A leads to B. No, what I am saying is that "temperature" is the same phenomenon as "molecules' movement" (more or less). The more movement, the more temperature, because they are two different ways of describing the same phenomenon.

In the second statement, I am saying that one event (supplying thermal energy to a reaction) will lead to another event (explosion of the beaker). The two events are not the same. There is, therefore, a causal relationship between them.

Now, let's see if we can guess which of the two statements the following are:

Friction is a result of interaction of the molecules of two surfaces.

Doing a mitzva increases oiros and keilim in Atzilus.