The above video is a very quick, fairly vague explanation of the difference between tempered and untempered chocolate.
Dan Souza, the editor of Cooks Illustrated magazine, illustrates tempered chocolate as a rigid, highly structured stacking of kitchen chairs as compared to an 'untempered', random arrangement of the same chairs.
I would appreciate a little more detail, maybe a micrograph or two, but what you see above is all Dan's giving us this time. Dan has, however, given a little more detail about chocolate in the video after the jump which includes a recipe for millionaire shortbread that requires tempering of the chocolate topping, something Dan shows how to do using a microwave.
I worked with a type of hydrogel in my one summer of actual benchtop research at Miami University twenty-some years ago, and I certainly never would have imagined them to have the properties described in today's video. I was just looking at the ability of the get to absorb and subsequently release transition metal ions, so I wasn't exploring their mechanical properties, admittedly.
SPNs, in case you were wondering, are supramolecular polymer networks, networks of polymer chains held together by - according to this video - non-covalent bonds like intermolecular forces like hydrogen bonds.
Halfway through the video, Hank makes a turn to a possible application of a particular SPN that was used to help paralyzed rats to regrow nerve cells and allow them to 'walk' again. That's a long way from human trials, but the initial study sounds amazingly promising.
Warning: NSFW words (mostly starting with f's) at 0:45...and at 3:43...and at 4:39...and at 4:57...and at 5:33...and at 7:26 and 7:31...and at 7:44...and at 8:42...and at 9:10...and at 10:45...and at a14:10
Ok, so maybe this shouldn't be shown in class.
I've long wondered how single crystal turbine blades are grown to be single crystals. We mimic this is far less complicated ways with our copper (II) sulfate crystal growth lab in our matsci class at Princeton (and in many other ASM-born matsci classes).
...but I knew that simplistic method clearly wasn't going to work for the cast metal structures for metallic crystals.
Thankfully this video's foul-mouthed Yorkie host explains how we go from molten metal to single crystal, grain-boundary-less macrostructures. It's not a very thrilling video as it's just a knowledgeable guy explaining things in his garage with a white board to show what he's talking about. I respect the knowledge and appreciate his explanation about something I've wanted to know for a while now.
Maybe just watch it and explain things to your students rather than showing the video itself.
...because the video itself is absolutely fandabidozi.
Admittedly, the fact that their first launch wasn't fully successful isn't anything to look at as a failure in my eyes. The fact that the first launch failed is sort of the benefit of the 3d printing process. One of their supposed benefits is the fact that the engineering cycle will be sped up, allowing iterations to happen in far more rapid succession than was previously possible.
So, good on ya, Relativity. I look forward to seeing your 3d-printed metal rockets in space someday soon...just not yesterday.
I've been looking for an amorphous metal demonstrator off and on for a few years but with no success.
There are some samples of amorphous metals available on ebay, but I really don't have any idea of what those metals actually are, whether they're really the zirconium-beryllium-titanium-copper-nickel alloy that Steve describes at 7:10 in this above video.
This video sees Steve explore how to optimize the bounces - which material should the ball bearing be made from, how big should the ball bearing be, how can you measure the number of bounces most easily - which is cute, but the big payoff in the video comes after around 10:00 when Steve explains how materials plastically deform and why amorphous metals don't easily deform plastically.
That's absolutely fascinating, and I even more desperately want one of these atomic trampoline demonstrators.
Feel free to hunt one down and buy me one for Christmas. I'll happily give you my address if you do get ahold of one.
Now I'm curious how an amorphous metal would respond to a hardness test. Would it be much tougher to create a traditional 'dent' from a hardness tester?
(In hunting down more info on amorphous metals, I might've found a preliminary answer to that one on the LiquidMetal website, scroll down partway to find hardness data.)
Here's more info about amorphous metals and a video from Grand Illusions, from whom Steve borrowed his atomic trampoline demonstrator.
