Removing "Friction" In-Game?

[WayneLigon]

For a good example of 'what happens if we change fundamental physics', read Stephan Baxter's novel 'Raft', set in a universe where the force of gravity is a billion times stronger than it is in ours.

 

[pawsplay]

Among other things, I am a physicist. To quote Wolfgang Pauli (of the quantum mechanical Pauli Exclusion Principle), "That is jot only not right, it is not even wrong."

At some point when I am not posting from my phone, maybe I will address some of the misapprehension of that... stuff.

Ok. I just think it's kind of a fundamental problem with the original concept is that friction arises because objects cannot simply pass through one another. I admit I am not, in fact, a physicist, but I'd like to hear more.

 

[Umbran]

Ok. I just think it's kind of a fundamental problem with the original concept is that friction arises because objects cannot simply pass through one another. I admit I am not, in fact, a physicist, but I'd like to hear more.

Very well, then, let's get back to it...

Friction is not a fundamental force.

Well, no, but it is ubiquitous in human existence.

It results from things like kinetic energy turning to heat, and from asperities (surface roughness).

So, this is backwards.

Yes, surface roughness enters into it. In the best models of friction, when two materials slide along each other, the microscopic peaks of their rough surface collide (Image Credit: modified from TotoBaggins, Mckdandy (CC BY-SA 3.0))...

In order to get past each other, those peaks must deform slightly. That deformation takes energy - a bit of the kinetic energy of the moving materials. And that work of flexing warms the surface - and effectively the kinetic energy is converted to heat. That warming is a result of friction though, and not a cause.

If those properties don't exist, your body doesn't convert kinetic energy to heat,

It is unclear what this is supposed to mean. The human body mostly warms itself through chemical oxidation processes - effectively by burning sugars, mostly.

and particles don't resist the movement of other particles. So you would just disperse.

Oh, no. Your body's cells have molecules (Cell Adhesion Molecules - CAMs) on them that connect to molecules on neighboring cells. Those intermolecular bonds are not about surface roughness, but about more direct intermolecular forces - just a little bit short of outright chemical bonds. That's generally stronger than the interactions of friction.

 

[pawsplay]

Very well, then, let's get back to it...

So, this is backwards.

Well, we're having a very strange conversation. The question was, what happens if you don't have friction? So my thinking was, what causes friction. Friction is the result of objects not being able to simply pass through each other. One of the consequences of that is that the energy that would normally be converted to something else when they collide is that they don't.

So let's say objects can pass through each other. They are no longer held in place by the presence of other objects. So the only thing holding objects together would be molecular attraction. Again, this is a very silly thought experiment. But it seems like everything would just be these non-Newtonian fluids. Maybe it's a lack of imagination on my part, but I think you would just be a puddle. Perhaps instead we would all be these amazing clouds constantly transforming into different shapes, or maybe forces would be so different that things mimicked matter as we know it in more respects, but is still weird, but that's so weird I don't even know how to world build around that.

I'm not wrong that friction is mostly caused by little things bumping into each other, right? So, I'm really stuck on the idea of a universe where, possibly at the visual level, a bunch of minerals could just rub together and their little irregularities... just passed straight each other without any collisions, without changing the energy of their motion into any other form.

 

[Umbran]

Well, we're having a very strange conversation. The question was, what happens if you don't have friction? So my thinking was, what causes friction. Friction is the result of objects not being able to simply pass through each other.

So, being picky and technical, no. Friction is the results of objects not being perfectly smooth on a microscopic scale, which is not at all the same thing.

But it seems like everything would just be these non-Newtonian fluids.

I don't know a reason why they'd specifically be non-Newtonian.

 

[aco175]

And here I was just thinking that I would get better gas millage.

 

[Cadence]

And here I was just thinking that I would get better gas millage.

Lot of tires spinning...

 

[pawsplay]

So, being picky and technical, no. Friction is the results of objects not being perfectly smooth on a microscopic scale, which is not at all the same thing.

I'm just fascinated by this. Is the issue not that the not perfectly smooth surfaces can't pass through each other? Is there something going on besides bumps?

 

[pemerton]

I'm just fascinated by this. Is the issue not that the not perfectly smooth surfaces can't pass through each other? Is there something going on besides bumps?

@Umbran will correct me if I'm wrong. But I took Umbran's point to be that there are non-smoothnesses.

Even if these things were perfectly smooth, they still wouldn't be able to pass through one another (presumably for a combination of electromagnetic reasons and Pauli-type reasons - again, I look to @Umbran for correction and/or elucidation). But they wouldn't generate friction, which - as per post 23 - is the process of irregular surfaces deforming in order to move past one another, thereby losing kinetic energy and generating heat.

 

[AbdulAlhazred]

What would be the effects of literally removing friction as a way physics behaves in your campaign world?

A little background. We're running a very limited campaign that will last until the teenagers leave for college. Their last quest is to get the Book of Law. The megalomaniac ruler of the city was wanting it to put his name in it to make his rule indisputable on a cosmic scale.

But one of the players (a senior on his way to engineering school) suggested "what if we can change the laws of physics - I've always hated friction."

So this is going to destroy the campaign world in interesting and funny ways ... a memorable way to end a short campaign with these players.

What I'm asking you ... what would this look like? I don't want to get the science completely wrong in front of my science-minded players.

I'd advise playing it for laughs. Friction isn't a single specific sort of thing. Frictional forces can arise for a variety of reasons, and in fact there's still some lack of understanding of some of the details. Additionally, some of these forces are also very important in other respects, so if you 'got rid of friction', what would happen to the viscosity of fluids? It just isn't one of those sorts of questions that, IMHO, has any really 'right answer'. So, I'd go ahead and come up with funny situations and outcomes and not worry about 'the science' because there simply is no plausible science.