Weekend project: Shoot your neighbor with your new water mortar

Just so no one accuses me of going soft and posting nothing but plush dolls all day, here is a cool water mortar you can make with a few chunks of PVC pipe, a couple of O-rings, and some assorted hardware. For those of you in colder regions, file this one away, summer will be here soon.

link

Weekend project - Non-newtonian fluids

Non-newtonian fluids is defined as a fluid that changes viscosity based on strain rate. What this means for us is that you can make a substance that sometimes acts like a liquid and at other times like a solid. A common name for is is "oobleck" which comes from the Dr. Seuss book Bartholomew and the Oobleck. If you mix 1 part cornstarch with 1.5 to 2 parts water, you get an Elmer's glue like goop. You can pour this from bowl to bowl, even scoop it up with a spoon if you move slowly. The fun happens when you move or push on the liquid quickly, at this point the viscosity decreases and it acts much more like a solid, allowing you to push it around, even roll it into a ball (although it turns back into liquid as soon as you stop rolling it).

Here's a couple of videos to get your interest flowing.





If the weather permits this weekend I'll post our oobleck video on Sunday