They filled a pool with a mix of cornstarch and water made on a concrete mixer truck. It becomes a non-newtonian fluid. When stress is applied to the liquid it exhibits properties of a solid. Video was recorded at Barcelona, Spain.
A non-Newtonian fluid is a fluid in which the viscosity changes with the applied strain rate. As a result, non-Newtonian fluids may not have a well-defined viscosity. Although the concept of viscosity is commonly used to characterize a material, it can be inadequate to describe the mechanical behavior of a substance, particularly non-Newtonian fluids. They are best studied through several other rheological properties which relate the relations between the stress and strain tensors under many different flow conditions, such as oscillatory shear, or extensional flow which are measured using different devices or rheometers. The rheological properties are better studied using tensor-valued constitutive equations, which are common in the field of continuum mechanics (From Wikipedia, the free encyclopedia, 2007)
Interesting. I am courious
Interesting. I am courious about the component ratio of the cornstarch to water to make such kind of non-Newtonian fluid.
Looking forward to watching more movies of mechanics
Thank you, Roy, for posting this terrific video and for providing background information. Next time I teach viscoelasticity I'll make a link to this post.
Fluid mechanicians have kept saying that over decades they have made many movies of interesting phenomena of fluids. I wonder if they are online now. Solid mechanicians seem to have less of a tradition of making movies, but there must be some good ones. People often play them at their seminars, but have not formed a habit to post them online. Why not? Your work can reach more people.
Thank you, Roy, for taking a lead on posting your own videos and videos made by others. We all look forward to watching more videos of mechanical phenomena.
In reply to Looking forward to watching more movies of mechanics by Zhigang Suo
The classical fluid mechanics films available at MIT
Dear Prof. Suo,
In 1961 the National Committee for Fluid Mechanics Films (NCFMF) produced a series of videos on phenomena in fluid mechanics. You can view them from the following website:
http://web.mit.edu/fluids/www/Shapiro/ncfmf.html
Many big names in fluid mechanics, such as G.I. Taylor and M.J. Lighthill, appeared in the film series and explained a variety of very interesting flow phenomena.
My professor in my Viscous Flow course used to play that video in class. I think most university libraries might have that video available.
In reply to The classical fluid mechanics films available at MIT by Zhi Huang
Re: The classical fluid mechanics films available at MIT
Dear Zhi:
Many thanks for pointing out this link. Apparently the movies cannot be downloaded. I'll check with our library. If you know of a place where people can view these movies free of charge, please point it out.
In reply to Re: The classical fluid mechanics films available at MIT by Zhigang Suo
Dear Prof. Suo: I used to be
Dear Prof. Suo:
I used to be able to play these movies directly from that website. However, it seems that it's not working now for some reason. Hope the library has some copies.
In reply to Looking forward to watching more movies of mechanics by Zhigang Suo
One technical issue to post more movies/videos to iMechanica
Dear Zhigang,
Thank you very much for your great suggestion. We should post more movies from our research work to iMechanica. Unlike this popular video and the “spiderman" (Teng posted it in 2006), our research videos are very specialized so need clear illustrations, e.g., similar to a PowerPoint page with a video and an illustration. However, I find it is difficult to do that using our edit software TinyMCE (click here for video posting tips by Teng). Hope some experts could solve this problem so we will watch more research videos in the near future.
Roy
In reply to One technical issue to post more movies/videos to iMechanica by L. Roy Xu
Videos and Online presentations
Dear Roy,
Enjoyed the movies you posted. I share with your concern on the difficulty of posting videos in TinyMCE. Even with the tips I posted, I still feel a little uncomfortable switching between regular editing mode and video posting mode. Maybe a better text editor can ease this process. I hope some Drupal gurus can give us some hints on this issue.
In an earlier comment, I discussed other possible ways for online presentation.
-Teng
Walking on "water" ...
Dear Dr Xu
Similar to the reponse of previous reader, I'm extremmely amused with the video of non-Newtonian fluid experiment in Spain. Thanks! It just reminds me of one scene in a movie "Crouching Tiger, Hidden Dragon" where someone was running (with his/her foot tip) on the water. I'd expect that the water, as a result of special effect, can be replaced with non-newtonian fluid in the future.
And, I'd like to see more movies presenting mechanics from this website.
Arief
Try cooking it....
...and the starch solution should become shear thinning instead. Rheology is utilised in many products, possibly one of the most infamous drinks is the Orbitz: http://en.wikipedia.org/wiki/Image:Orbitzsoda.jpg.