# Other common non-Newtonian fluids? **URL:** \ **Category:** Factual Questions\ **Created:** [March 11, 2008, 6:25pm UTC](https://boards.straightdope.com/t/other-common-non-newtonian-fluids/440992 "2008-03-11T18:25:02Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![CC](https://avatars.discourse-cdn.com/v4/letter/c/f1d935/32.png) [@CC](https://boards.straightdope.com/u/CC)\ **Post date:** [March 11, 2008, 6:25pm UTC](https://boards.straightdope.com/t/other-common-non-newtonian-fluids/440992/1 "2008-03-11T18:25:02Z")
Aside from the old cornstarch and water mixture, are there other common materials that can be used to form one of these bizarre substances? Also, why do cornstarch molecules act this way and other large molecules do not? Are they shaped like stacking chairs in a way? ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [March 11, 2008, 6:38pm UTC](https://boards.straightdope.com/t/other-common-non-newtonian-fluids/440992/2 "2008-03-11T18:38:45Z")
Plenty of them – honey, dishwashing liquid, Silly Putty, ketchup, latex paint. They’re Non-Newtonian because the viscosity changes with strain,. Most of them don’t change the same way the corn starch and water mixture (:oobleck") does, but they’re non-Newtonian none the less. Check out this: > **[Non-Newtonian fluid](https://en.wikipedia.org/wiki/Non-Newtonian_fluid)** > > A non-Newtonian fluid is a fluid that does not follow Newton's law of viscosity, that is, it has variable viscosity dependent on stress. In non-Newtonian fluids, viscosity can change when under force to either more liquid or more solid. Ketchup, for example, becomes runnier when shaken and is thus a non-Newtonian fluid. Many salt solutions and molten polymers are non-Newtonian fluids, as are many commonly found substances such as custard, toothpaste, starch suspensions, corn starch, paint, bl Mo... ---
**Author:** ![CC](https://avatars.discourse-cdn.com/v4/letter/c/f1d935/32.png) [@CC](https://boards.straightdope.com/u/CC)\ **Post date:** [March 11, 2008, 6:59pm UTC](https://boards.straightdope.com/t/other-common-non-newtonian-fluids/440992/3 "2008-03-11T18:59:59Z")
Ok, then I guess my question more specifically is are there any common non-Newtonian fluids that behave like the cornstarch/water mix? I think Silly Putty does, but in a much slower way, oozing slowly like a liquid when left to do so, and rebounding like an elastic solid when bounced. The others mentioned don’t seem to. ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [March 11, 2008, 7:20pm UTC](https://boards.straightdope.com/t/other-common-non-newtonian-fluids/440992/4 "2008-03-11T19:20:11Z")
Quicksand does, which is why they made the cornstarch-and-water mix for that Mythbusters episode on quicksand. ---
**Author:** ![CC](https://avatars.discourse-cdn.com/v4/letter/c/f1d935/32.png) [@CC](https://boards.straightdope.com/u/CC)\ **Post date:** [March 11, 2008, 7:43pm UTC](https://boards.straightdope.com/t/other-common-non-newtonian-fluids/440992/5 "2008-03-11T19:43:16Z")
If I read the Wiki article correctly, quicksand is a non-Newtonian fluid that acts in the exact _opposite_ way of the cs/w mix. To wit- when it’s stressed, it changes character from solid to liquid. But even that would be difficult to experiment with. I’m looking for another mixture using common materials to explore the phenomenon. I believe, unless I can find some others, that cs/w is close to unique, at least with respect to readily available substances. ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [March 11, 2008, 8:05pm UTC](https://boards.straightdope.com/t/other-common-non-newtonian-fluids/440992/6 "2008-03-11T20:05:27Z")
I’m not sure about quicksand, but wet water-soaked sand behaves the same way. You can see it on the beach - footsteps form and then melt away slowly. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [March 11, 2008, 11:52pm UTC](https://boards.straightdope.com/t/other-common-non-newtonian-fluids/440992/7 "2008-03-11T23:52:49Z")
I don’t know the formulation, but I’ve heard that the military is experimenting with ooblek-like materials for body armor. If a bullet or piece of srapnel hits it, it firms up enough to protect the wearer, but at other times, it’s pliable enough to allow easy movement. ---
**Author:** ![El\_Kabong](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/el_kabong/32/496_2.png) [@El\_Kabong](https://boards.straightdope.com/u/El_Kabong)\ **Post date:** [March 12, 2008, 1:12am UTC](https://boards.straightdope.com/t/other-common-non-newtonian-fluids/440992/8 "2008-03-12T01:12:27Z")
Most oil and gas wells are drilled while circulating non-newtonian drilling fluids, or ‘muds’, which may be water- or oil-based, and whose primary purpose is to evacuate the drill cutttings from under the bit and bring them to surface. These exhibit the opposite effect to that described in the OP, or so-called shear thinning. The fluid, which usually contains bentontic clays and/or polymers for increased viscosity, is relatively ‘thin’ when circulated, but relatively ‘thick’ when at rest. This has the beneficial effects of allowing relatively low pumping pressures while circulating, and of keeping drill cuttings suspended, at least temporarily, when circulation stops. Early drilling fluids were simply pumped water, into which natural clays found in the drilled formations tended to dissolve. Drillers noticed that these natural-clay muds tended to provide better hole cleaning, and the industry gradually began to engineer fluids with improved viscosity properties. The increased viscosity occurs more or less because the tiny particles of clay (or polymers) supended in the mud, link weakly to each other. As an approximation, when the mud is at rest, more particles tend to be linked than when circulating, hence the increase in apparent viscosity, or ‘thickness’ of the fluid. ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [March 12, 2008, 1:55am UTC](https://boards.straightdope.com/t/other-common-non-newtonian-fluids/440992/9 "2008-03-12T01:55:56Z")
[QUOTE=El\_Kabong] These exhibit the opposite effect to that described in the OP, or so-called shear thinning. The fluid, which usually contains bentontic clays and/or polymers for increased viscosity, is relatively ‘thin’ when circulated, but relatively ‘thick’ when at rest. [/QUOTE] Shampoo also behaves this way, as shown in this [video of the Kaye effect.](http://www.maniacworld.com/The-Kaye-Effect.html) ---
**Author:** ![Santo\_Rugger](https://avatars.discourse-cdn.com/v4/letter/s/e95f7d/32.png) [@Santo\_Rugger](https://boards.straightdope.com/u/Santo_Rugger)\ **Post date:** [March 12, 2008, 3:44am UTC](https://boards.straightdope.com/t/other-common-non-newtonian-fluids/440992/10 "2008-03-12T03:44:09Z")
There are two types of non-Newtonian fluids. The first, shear thinning, is more common in everyday life. These are fluids that experience a decrease in viscosity when exposed to a shear stress. My favorite example is toothpaste; it doesn’t flow until you add some shear force by squeezing the tube. These are often known as _psuedoplastics_. The second type, the type you’re asking about, are shear thickening substances. This means the viscosity increases with respect to shear force. It is necessary to point out that this change is not necessarily linear, and can, in fact, be exponential. These are often known as _dilatants._ As mentioned earlier, these materials are being used for experimental body armor, but dilatant petroleum polymers\* can also be used in transfer cases on vehicles. The more stress put on the fluid, the more viscous it becomes, and the more power it can transfer. Wiki has a good, albeit short, article [here.](http://en.wikipedia.org/wiki/Dilatant) - I think they’re petroleum polymers, but don’t quote me on that one!