# Frictionless Fluid **URL:** \ **Category:** Factual Questions\ **Created:** [February 25, 2010, 10:19am UTC](https://boards.straightdope.com/t/frictionless-fluid/530375 "2010-02-25T10:19:57Z")\ **Posts on this page:** 16\ **Page:** 1
**Author:** ![Steven\_Graves](https://avatars.discourse-cdn.com/v4/letter/s/bc79bd/32.png) [@Steven\_Graves](https://boards.straightdope.com/u/Steven_Graves)\ **Post date:** [February 25, 2010, 10:19am UTC](https://boards.straightdope.com/t/frictionless-fluid/530375/1 "2010-02-25T10:19:57Z")
I wanted to know if it is possible for a fluid to have negative friction ’ that is if its possible for a fluid to be frictionless I dont personaly think its impossible but the implications of this kind of natural Phenomenon would certainly be far reaching Apparently this theory (As the title suggests) is purely theoretical And as i dont have the time to web surf for the next 12 years in search of the answer ’ i was hopeing you could And if this theory was proven correct ’ what are the general implications regarding Well . . . . . Whatever it would effect? ---
**Author:** ![ErwanBD](https://avatars.discourse-cdn.com/v4/letter/e/5f9b8f/32.png) [@ErwanBD](https://boards.straightdope.com/u/ErwanBD)\ **Post date:** [February 25, 2010, 10:42am UTC](https://boards.straightdope.com/t/frictionless-fluid/530375/2 "2010-02-25T10:42:48Z")
One word : superfluidity > **[Superfluidity](https://en.wikipedia.org/wiki/Superfluid)** > > Superfluidity is the characteristic property of a fluid with zero viscosity which therefore flows without any loss of kinetic energy. When stirred, a superfluid forms vortices that continue to rotate indefinitely. Superfluidity occurs in two isotopes of helium (helium-3 and helium-4) when they are liquefied by cooling to cryogenic temperatures. It is also a property of various other exotic states of matter theorized to exist in astrophysics, high-energy physics, and theories of quantum gravity.\[1... ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [February 25, 2010, 10:56am UTC](https://boards.straightdope.com/t/frictionless-fluid/530375/3 "2010-02-25T10:56:06Z")
The term ‘negative friction’ would tend to suggest something that acts in such a way as to accelerate something, rather than slowing it down or allowing it to continue to move unimpeded at the same velocity - which would require an energy input. A potentially close match to what you’re looking for might be superfluids - [Superfluidity - Wikipedia](http://en.wikipedia.org/wiki/Superfluid) ---
**Author:** ![zut](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/zut/32/2875_2.png) [@zut](https://boards.straightdope.com/u/zut)\ **Post date:** [February 25, 2010, 12:12pm UTC](https://boards.straightdope.com/t/frictionless-fluid/530375/4 "2010-02-25T12:12:12Z")
> [@Steven\_Graves](#): > > I wanted to know if it is possible for a fluid to have negative friction ’ that is if its possible for a fluid to be frictionless I think what you’re looking for is a fluid with zero [viscosity](http://en.wikipedia.org/wiki/Viscosity), which is a property of a superfluid. Viscosity is a measure of how well a fluid will transmit shear stress perpendicular to the flow, or how strongly it will “pull along” adjacent fluid. So viscosity is analagous to friction. You’re not going to find any substance with _negative_ viscosity. As **Mangetout** said, negative viscosity implies the spontaneous acceleration of fluid, which is an energy gain. For the same reason, you can’t have a negative friction coefficient between solid surfaces: this would imply you could step onto “negative friction ice” and it would accelerate you across the pond. ---
**Author:** ![ZenBeam](https://avatars.discourse-cdn.com/v4/letter/z/3ab097/32.png) [@ZenBeam](https://boards.straightdope.com/u/ZenBeam)\ **Post date:** [February 25, 2010, 1:31pm UTC](https://boards.straightdope.com/t/frictionless-fluid/530375/5 "2010-02-25T13:31:07Z")
To have negative viscosity, you’d have to have a situation analogous to that of a laser, where the fluid has some of its atoms in an excited state, able to drop into a lower energy state, to provide the energy for the accelerating fluid. I have never heard of such a thing, but it’s at least potentially possible. ---
**Author:** ![Bytegeist](https://avatars.discourse-cdn.com/v4/letter/b/9dc877/32.png) [@Bytegeist](https://boards.straightdope.com/u/Bytegeist)\ **Post date:** [February 25, 2010, 3:42pm UTC](https://boards.straightdope.com/t/frictionless-fluid/530375/6 "2010-02-25T15:42:33Z")
> [@zut](#): > > For the same reason, you can’t have a negative friction coefficient between solid surfaces: this would imply you could step onto “negative friction ice” and it would accelerate you across the pond. … also known as the _Toyota Effect_. ---
**Author:** ![Pleonast](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pleonast/32/1183_2.png) [@Pleonast](https://boards.straightdope.com/u/Pleonast)\ **Post date:** [February 25, 2010, 6:35pm UTC](https://boards.straightdope.com/t/frictionless-fluid/530375/7 "2010-02-25T18:35:56Z")
> [@ZenBeam](#): > > To have negative viscosity, you’d have to have a situation analogous to that of a laser, where the fluid has some of its atoms in an excited state, able to drop into a lower energy state, to provide the energy for the accelerating fluid. > > I have never heard of such a thing, but it’s at least potentially possible. I was going to say something similar. If you put a superfluid in a bucket, and slowly started the bucket rotating, the superfluid will stay stationary. However, there might be some perturbation one could make that would briefly couple the superfluid with the spinning bucket. The superfluid would then gain more angular momentum than imparted by the perturbation (gaining some from the bucket as well)–effectively giving the interaction a “negative” viscosity. ---
**Author:** ![Steven\_Graves](https://avatars.discourse-cdn.com/v4/letter/s/bc79bd/32.png) [@Steven\_Graves](https://boards.straightdope.com/u/Steven_Graves)\ **Post date:** [February 26, 2010, 6:51am UTC](https://boards.straightdope.com/t/frictionless-fluid/530375/8 "2010-02-26T06:51:52Z")
How interesing . . . . . . . I just wanted to put the resulting fluid into a water gun But this has raised my left eyebrow ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [February 26, 2010, 8:34am UTC](https://boards.straightdope.com/t/frictionless-fluid/530375/9 "2010-02-26T08:34:31Z")
Can a superfluid be stirred? ---
**Author:** ![Gbro](https://avatars.discourse-cdn.com/v4/letter/g/c6cbf5/32.png) [@Gbro](https://boards.straightdope.com/u/Gbro)\ **Post date:** [February 26, 2010, 2:24pm UTC](https://boards.straightdope.com/t/frictionless-fluid/530375/10 "2010-02-26T14:24:06Z")
> [@Steven\_Graves](#): > > How interesing . . . . . . . > > I just wanted to put the resulting fluid into a water gun > > But this has raised my left eyebrow [Then use one of these guns;).](http://www.sharperimage.com/Toys+Leisure/AirZooka+Hand+Held+Air+Cannon.axd) ---
**Author:** ![running\_coach](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/running_coach/32/15836_2.png) [@running\_coach](https://boards.straightdope.com/u/running_coach)\ **Post date:** [February 26, 2010, 2:39pm UTC](https://boards.straightdope.com/t/frictionless-fluid/530375/11 "2010-02-26T14:39:14Z")
> [@Mangetout](#): > > Can a superfluid be stirred? No, shaken. ---
**Author:** ![billfish678](https://avatars.discourse-cdn.com/v4/letter/b/7bcc69/32.png) [@billfish678](https://boards.straightdope.com/u/billfish678)\ **Post date:** [February 26, 2010, 2:44pm UTC](https://boards.straightdope.com/t/frictionless-fluid/530375/12 "2010-02-26T14:44:56Z")
> [@Mangetout](#): > > Can a superfluid be stirred? Thats a very good question. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [February 26, 2010, 2:45pm UTC](https://boards.straightdope.com/t/frictionless-fluid/530375/13 "2010-02-26T14:45:59Z")
> [@runner pat](#): > > No, shaken. Well played sir. (but the question remains - if you’ve got a tumbler full of superfluid that has no viscosity and is frictionless, what happens if you put a spoon or paddle in there and start moving it about? ---
**Author:** ![BubbaDog](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bubbadog/32/333_2.png) [@BubbaDog](https://boards.straightdope.com/u/BubbaDog)\ **Post date:** [February 26, 2010, 8:48pm UTC](https://boards.straightdope.com/t/frictionless-fluid/530375/14 "2010-02-26T20:48:49Z")
> [@Mangetout](#): > > Well played sir. > > (but the question remains - if you’ve got a tumbler full of superfluid that has no viscosity and is frictionless, what happens if you put a spoon or paddle in there and start moving it about? I think it’s going to fly out of the bucket and hit the jet on the conveyor belt. ---
**Author:** ![zut](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/zut/32/2875_2.png) [@zut](https://boards.straightdope.com/u/zut)\ **Post date:** [February 27, 2010, 4:21am UTC](https://boards.straightdope.com/t/frictionless-fluid/530375/15 "2010-02-27T04:21:16Z")
> [@Mangetout](#): > > (but the question remains - if you’ve got a tumbler full of superfluid that has no viscosity and is frictionless, what happens if you put a spoon or paddle in there and start moving it about? [Inviscid flow](http://en.wikipedia.org/wiki/Inviscid_flow), which is something of a circular definition, but a standard fluid dynamics simplification. Remember the fluid still has mass, even if it doesn’t have viscosity, and the free surface and walls of your tumbler affect any flow. ---
**Author:** ![Steven\_Graves](https://avatars.discourse-cdn.com/v4/letter/s/bc79bd/32.png) [@Steven\_Graves](https://boards.straightdope.com/u/Steven_Graves)\ **Post date:** [March 7, 2010, 6:56am UTC](https://boards.straightdope.com/t/frictionless-fluid/530375/16 "2010-03-07T06:56:57Z")
> [@Mangetout](#): > > Well played sir. > > (but the question remains - if you’ve got a tumbler full of superfluid that has no viscosity and is frictionless, what happens if you put a spoon or paddle in there and start moving it about? I would imagine it would create a supernova inside of a black hole for no reason yesterday tomorow right now