I read a scene from a sci-fi book where the characters come across a space ship covered with frictionless black paint. They reach out to touch it, but have trouble, as their hands merely glance off. Each time they touch the surface, they can not feel anything.
Scoffing, and thinking this is not how it would work, I have ordered myself a special table. It is made entirely of unobtanium – a particular variety of unobtanium that violates several laws of thermodynamics in order to grant it the special property of frictionlessness.
It arrives in a few days. What should I expect? When lay my palm down on the tabletop, what will the tactile sensation be? Say the surface is textured – will I be able to tell? If the specific heat capacity and thermal conductivity of this unobtanium are otherwise unremarkable, will I notice a difference in the temperature of my sans-friction table? What about visually: does friction affect how light interacts with a surface?
On a side note, I ordered this table from Ikea, so I’ll have to assemble it myself. What special concerns will there be in assembling furniture, all of whose constituent pieces are perfectly frictionless?
Fun question. Lastly, I think it will be hard to keep the thing together with screws, nails, or nuts or bolts, since they work by friction. You can certainly touch surfaces that have very low friction. You can feel them, just as easily as you can feel frictionful surfaces, so one way of thinking about it is that the surface will feel pretty much the same as any material. On another hand, it might feel like it feels when you push two magnetic north poles together - a sort of slip/slide. I’m interested in the thread. I’ll stay tuned.
Well, since Teflon has one of the lowest (the lowest?) coefficients of friction of any materials out there and when touched, it feels like it is covered with liquid, I would venture a guess that a totally frictionless surface would feel like an oily surface that left no residue. When you push down directly on Teflon, it feels like a relatively normal surface (i.e. you can sense pressure); only when you have a side-to-side motion do you sense the slickness.
If the surface is textured, the overall effect is not going to be one of frictionlessness - if it’s covered with little bumps and you place your hand flat on it, then try to slide it sideways, in order to ride over the bumps, parts of your hand will have to flex and be pushed up against gravity and against any force you are applying. That will feel a bit like friction, especially if the texture is fairly fine-grained, but deep.
The “solidness” of matter has nothing to do with it’s friction, it has to do with (IIRC) the electromagnetic force holding the atoms together. Or maybe it’s the strong force…weak force?
Actually, those two things are inextricably intertwined. The exact same force (the electromagnetic, as you surmised) which makes things feel solid is also responsible for friction.
I feel like it might not be unlike the sensation of a novocained tongue, where you can feel contact and pressure, but not the scraping, dragging sensation of normal touch.
Just wanted to jump in and say that the table will be fun to play with. An item placed on it’s surface and then pushed, will move until it falls off, or air resistance stops it. Ultimate “air” hockey table!
As for it’s construction, I imagine it being held in place with… I don’t know what their called. Like tounge and groove, but the tounge goes all the way through the piece it’s connecting to, and then a pin is put in place to hold it. Very 70’s!
I second that it would feel like a cold, slimy, wet surface. It wouldn’t somehow negate your tactile senses so you’d feel nothing, as friction only really offers resistance and heat from that resistance. You’d still be able to touch it.
I was thinking embedded rare earth magnets instead. It would probably be best not to leave credit cards or electronics anywhere near that table, though.
At what degree of smallness does “texture” stop being texture and start being friction?