A couple of days ago I wrote about
a Google employee who mashed together 250 lbs of Silly Putty and then had a hard time breaking it up into chunks.
Today Dr. Paul J. Camp, from the Department of Physics at Spelman College in Atlanta, GA emailed me to say:
"I guess they didn't try smacking it with a hammer.
"Silly Putty is a bizarre polymer, but like most polymers it has a transition temperature at which its physical properties change. In this case, there is a glass transition temperature (Tg) -- below Tg, the polymer will behave like a glass and shatter on impact instead of deforming. For example, PVC has a Tg of 83 C which makes it a reasonable choice for cold water pipes but not for hot water, which would cause it to flow like Silly Putty (addition of various plasticizers can adjust the Tg). However, often the viscoelastic properties of polymers have a rate dependence and this is the case for Silly Putty. Do the same amount of work over a much shorter time (smack it with a hammer instead of pulling) and the SP behaves as if its Tg has been raised. It then shatters into bits.
"You can read a mildly confusing scientific explanation here (from Case Western) along with pictures of Silly Putty subjected to the same force at different rates, or if you prefer a more visceral experience, watch the video from this experiment of what happens when you drop a 50 pound beach ball made of Silly Putty off the roof of a building."
I asked Amy Parness, the co-founder of Sparkle Labs, maker of fantastic educational electronics kits, to write a Medium post about gender and the business of being a maker business person. Her terrific essay calls out the problems with “pink girly engineering kits.” From Medium:
Zero UI is the new term for “invisible interfaces”—what happens in the future when all the clicking and tapping and typing is history: “If you look at the history of computing, starting with the jacquard loom in 1801, humans have always had to interact with machines in a really abstract, complex way.” [Fast Company]
CEO Dick Costolo will resign, to be replaced in the interim by Jack Dorsey
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