Are solid objects really solid?

I am coming to love Alpha Phoenix's videos more and more with each video. He explores concepts that are often ridiculously subtle until you think about them a little more deeply, and he uses them to explain the details of the materials around us.

In this video he asks how long it would take for a force - a hammer hit in this case - on one end of a bar of steel to be felt on the opposite end of the bar. It's something that seems obvious at first because a push on one end of a steel bar is 'immediately' felt at the other end of the bar. That's true on the scale of a bar a couple of feet long and with the time scale that you and I notice things, but Alpha Phoenix uses far faster measurements than his eyes and proves that the force isn't felt 'immediately' on the other end.

And then he explains why this happens using magnets and springs representing the particles within a solid and does it brilliantly.

Now I just want him to make more of his videos. At his current pace, he's putting out a video a month or so which leads to high quality videos, but I just want more of them.

Build and Modify the World Around You with FORMcard | WIRED

I need to buy myself some Formcards (available here in the US - don't search Amazon because their selection is crap and ridiculously pricey).

I really dig the colors, and I'm looking forward to using them to demonstrate the idea of glass transitions in polymers (something we've seen before on the blog).

Is Glass a Liquid?

Glass...pitch...molten magma...all not quite liquid or solid...

The title says it's about glass, but the video actually is more about amorphous solids and viscosity in general. They're concepts well covered here by Dr Derek Muller of Veritasium.

Making SOLID Nitrogen!

Liquid nitrogen, sure. We have that in dewar flasks from time to time.

Gaseous nitrogen, yeah, we have that at all times around us.

Solid nitrogen, though, that we don't get to see very often.

Then along comes Dr Derek Muller of Veritasium with a better dewar and a vacuum pump to produce a gorgeous, spinning disk of solid nitrogen floating like the thinnest, coldest hovercraft in the world.

I've actually seen crystalline nitrogen in my classroom before with a far less impressive set-up that Dr Muller used. I put a 50mL beaker (or maybe a 100mL, I don't remember) in a plastic bell jar attached to a decent but not world-class vacuum pump. As the pressure dropped, the temperature dropped as well, cooling the liquid nitrogen further and eventually hitting the freezing point of nitrogen at low pressure.

The liquid nitrogen froze into a puffy, crystalline network atop the liquid. Then the liquid boiled violently, pushing the crystals out of the way and turning them back to liquid. Liquid to solid to liquid to solid...boiling then calming down again and again.

It was quite a show.

microstructure grain growth simulation

In high school I won tickets to an Allman Brothers Band concert from a local radio station. At the concert they had an old-school, bubbles-of-oil-and-colored-water on an overhead projector light show.

For some reason this video reminds me of that light show every time I see it. Yeah, it's a simulation of crystal growth showing 'grains' growing together, but I can imagine that it would be a bit more fascinating with some music and recreational drug use (not that we - ASM, Master Teachers, the DAR, the LDS, or Jeff Bridges - would ever endorse that.

We do, however, fully endorse using this video in our summer teacher workshop powerpoints.

Fake science: common crystal shapes

 

The Fake Science tumblr is exactly what it says, FAKE science...

...but it's funny science - including this post about common crystal shapes.

How to make Magic Mud

Yes, making your own 'Magic Mud' instead of just buying cornstarch and mixing it up sounds like a whole lot of extra work.

Yes, it's certainly cheaper to buy a box of conrstarch than to buy a whole five-pound bag of spuds.

But think of all the hasbrowns you can make (in case there isn't a Waffle House close enough to where you live.)

Honestly, though, I might offer this up as an extra credit opportunity for some of my students.

World's Roundest Object!

Be careful when discussing this video with your students. This is about the world's roundest sphere...sphere. It's not a ball. It's a sphere.

Just saying.

'Cause I know I've said ball in front of my high school students, and it took me a while to get the boys' attention back.

(In a related aside, my wife is listening in as this video plays. She lost control at 6:22 when the narrator said "Newtons, Joules". To quote her: "heh, heh...Newton's jewels...heh, heh".)

This 'world's roundest object' is more about the basis of our metric (now the systemé international d'unités or SI) than it is about materials science. There are, however, some serious challenges involved in making a material that won't decompose, that won't get dirty, that won't wear away, that won't change over time.

Here they have created - according to the scientist at 7:25 - a single crystal of silicon with 'no voids or dislocations' and containing only one isotope of silicon, making the material just slightly less valuable than absolutely, perfectly, priceless.

Graphene aerogel is the new world's lightest substance

As research into aerogel continues, scientists are discovering ever-lighter variations. First, there was carbon nanotube aerogel, with a density of 4 milligrams per cubic centimetre. Then along came silica aerogel, which weighed in at 1 milligram per cubic centimetre and garnered 15 entries in Guinness World Records. It was ousted by metallic microlattices, at 0.9 milligrams, and then aerographite, at 0.18 milligrams.

Now, a new graphene aerogel created by scientists led by professor Gao Chao at the Zhejiang University has swept past, weighing in at just 0.16 milligrams per cubic centimetre

The original article is from Nature, but only an abstract is viewable online for free, sadly. The full article takes a little bit of money that I'm not willing to spend ($8 for the one article or $199 for a year's subscription). Luckily there is a decent enough report on CNET Australia's blog (the source of the above quote).

Aerogels are odd, weird substances. I have a piece in a plastic container that I've taken out a few times to hold it. Each time it feels like I'm holding a solid and a gas at the same time. It's a contradictory feeling, a real-life discrepant event without a trick. The aerogel that I have - now snapped in two by another ASM master teacher, arggh - is a silica aerogel (available from Educational Innovations, one of our summer camp sponsors) which means it's something in the order of six times more dense than is this new graphene aerogel.

I, of course, want some of the new stuff.

Because it's the newest...

PS - There are other possible sources for the purchasing of silica aerogels - United Nuclear (small pieces in semi-bulk only), ebay (including, as of today, a huge 220cc sample), ThinkGeek, and BuyAeroGel.com.

What if: cornstarch

Randall Monroe is the creator of XKCD, a sometimes not-quite-school-appropriate cartoon that involves a mixture of computer-, engineering-, math-, and science-based humor (along with a bit of Randall's personal life mixed in here and there). Randall Munroe comes by his humor honestly as he's a former NASA roboticist and programmer.

One of Munroe's many side projects is What-If in which he answers ridiculous questions using solid science research. Most of the questions are absolutely ridiculous - how would a small plane fly in the atmosphere of Jupiter?, is it possible to create a jetpack by firing machine guns downward? - but every now and again he gives us a wonderful materials science question.

Recently we got "How much cornstarch could I rinse down the drain before unpleasant things start to happen?"

I'm absolutely thrilled that Munroe eventually makes the connection between the conrstarch and the great Boston Molasses Flood of 1919.

PS - personally, my favorite question had nothing to do with materials science.

Gorgeous photography of the elements

Sure it's possible to take some pretty decent photos with the Kena, and the price isn't too unreasonable. In the long run, though, a great photographer with a really nice camera can just outclass what you and I might be able to manage in the classroom.

( monoclinic sulfur - source)

Yes, there's value in having the students see the crystals grown, in letting them adjust the cooling rate to change the crystal sizes, allowing them to smell the sulfur in the air.

But there's also value in seeing some really gorgeous photos of crystals, like this stunning palladium sample...

(palladium - source)

There are all of these and a whole lot more available over on the Flickr galleries of R Tanaka:

• the elements
• minerals
• crystals

Tip of the hat to Neatorama for posting about these great photos.

Cornstarch monster - non-Newtonian fluid on speaker

There isn't really anything too new and revolutionary in this video. It's pretty standard cornstarch and water on a speaker. It just happens to be very well done, showing the cornstarch mixture releasing entirely from the speaker. We also get some explorations of varying cornstarch/water ratios.

Fun stuff...

Turn Pennies Silver and Gold (chemistry trick)

In our workshops we use a procedure that I greatly prefer to the one shown in this video, but the 'trick' of turning pennies to gold never gets old. Sure it's a brass alloy of copper and zinc, but it looks like magic.

What is graphene

Graphite is one of the allotropes of carbon - along with diamond and buckminsterfullerenes (buckyballs). Graphite exists as a series of hexagonal-based carbon layers, a single layer of which is known as graphene, the exploration of which lead to the awarding of the 2010 Nobel Prize in Physics.

In this video the structure and electrical properties of graphene are explained in very simple, udnerstandable language.

Silk - If spiders and worms can do it, why can't we?

Biomimetics is a fascinating field in which scientists take inspiration from the natural world to improve out technologies. Here a video from the National Science Foundation looks at one of the major struggles that scientists are trying to overcome in making artificial spider silk - particularly at the difficulty in storing liquid spider silk until it is solidified after it comes through the spinnerets.

Hard Candy Chemistry!

It can be daunting to do glass batching. You need a kiln, DFCs crucibles, and a fair bit of confidence. Sometimes it's easier to purchase the DFCs than it is to build up the confidence.

Working with candy, however, takes a lot less confidence because the worst that can usually happen is a nasty, blackened pot, and there's a lot that can be learned about glass by using candy as an analogue.

Plus, if you do it right, you get a sweet reward at the end.

MIT: Bottle coating speeds up ketchup pouring

I don't know that leftover ketchup in bottles is one of our society's greatest problems, but I certainly understand that being able to get all the food out of all of its containers would reduce food waste by a a few teaspoons per jar which would add up to a significant savings when added up.

Plus there's the fact that watching ketchup (I'm not going to type catsup, it bugs me) just glide out of the bottle is phenomenally cool.

Ross Nanotechnology Introduction

There's slick and then there's slick.

Ross Nanotech produces NeverWet coating - for which I may just be first in line because it's so cool. They're presented as being super-hydrophobic, meaning that they repel water and any water-based solution - with remarkable efficiency.

A little hydrophobic coating - ScotchGuard and the like - prevents some staining on fabric, but a superhydrophobic coating would make fabrics nearly unstainable - at least from any water-based liquid.

Big Bang Theory: So Funky

I'm assuming that this video will be un-embeddable soon. Most of the Big Bang Theory videos are - unless they're hosted by CBS itself.

Putting oobleck on a speaker can be a great, great time. I particularly recommend something with a massive, thumping bass line and little else. Most actual songs have too many other tones - maybe try a pure tone generator hooked up to an amplifier.

Surprisingly to our Princeton students, "Superbass" is awful for this.

Liquid armor

I dig the liquid body armor video that we show in our summer ASM workshop powerpoint, but I like this video way better.

The video quality's better. The science explanation is deeper. I dig the closeup views of the treated fabric.

Either way, they're both the same - or very similar - applications of the oobleck idea - that of a non-newtonian fluid.