Does the surface area of an object have an effect on the friction value? Apparently, the answer is "no"

Apparently, the answer, according to students and my teacher, is no. How is this possible? Doesn't increased surface area increase friction?

Or, does "friction value" mean something else?

Friction value is a vague term. For example, an object moving through the air or water experiences the friction of the air or water, and that DOES depend on the area.

And an object sliding on a surface also has friction. In that case, if you changed the area in contact with the surface WITHOUT changing the weight, then the friction does not change (ideally) because the weight is spread out over the larger area, and the weigh per unit area goes down. But that is ideal only, in actual fact, it does change.

And, if the contact area increases and the weight increases also, then the friction does go up.


So teach is right but only in a very narrow view of friction, and under the conditions I noted.