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The Secret of Cornstarch Physics
sciencehabit writes "Filling a small swimming pool with cornstarch and water has long been a physicist's party trick. Step onto it slowly and you'll sink, but run across quickly and the oozy mixture will support your weight — almost as though it has turned from liquid to solid. Several reasons have been offered for the phenomenon, but now researchers believe they have the real answer. The key to figuring things out: plunging a 370-gram aluminum rod from a slingshot at around 1 meter per second into a cornstarch suspension." One meter per second doesn't seem very fast for anything launched by a slingshot, but any speed is good as long as it advances important knowledge like this.
Has anyone made the Sugru clone by mixing silicone I caulk and cornstarch (I think ratios are flexible, up to 1:3 with reasonable cure times)?
As I understand it, the cornstarch absorbs the water and accelerates the silicone cure time, enabling a cure phase where it is hand-moldable like Sugru?
I have a box of corn starch and two tubes of silicone waiting at home for me to try this. There's an instructable for this that focuses on a different project but a lot of the project is spent on making this hand-moldable silicone.
I use Harvey plumber's epoxy (moldable, like clay, but gets rock hard) all the time and I've always wanted a hand-moldable product that would have the finished consistency of silicone. Silicone itself is too goopy and cures poorly if very thick.
Sugru solves this, but its expensive. There are other two-part silicones that can be bought, but they are expensive, too, and this method seems pretty simple and inexpensive (I think I bought two full-size tubes of GE brand Silicone I and a box of cornstarch for about $6, certainly less than $10 total).
I really wonder about that slingshot... why not just drop the bar from 5cm above? 1m/s is the speed it reaches when dropped from that height.
(actually, I think the journalists fucked up the numbers again)
In Rod We Trust.
(or, more appropriate to the topic : In, Rod We Thrust).