Tuesday, June 30, 2015

Shape It! Sand 5lb

We don't all have access to a local beach on which to do our metal casting. If you do have access to a beach, go for it, have a blast, just don't send us photos. Nobody else wants to see your beach photos while we're sitting at home in a landlocked state. Just quit it, Amanda.

If, however, you're nowhere near a beach, you're going to need to get yourself some nearer sand for metal casting. In particular, I like the Shape It! Sand (available under a few different brand names). Shape It! stays nice and moist thanks to some polymer additives that stay permanently moist, letting the sand pack together well into whatever little butter tub (or similar container - maybe something metal just in case the molten tin - because that's what I use in class) you're going to be pouring your metal.

And the best price around for Shape It! Sand is at Fat Brain Toys, $18.95 for five pounds of the stuff in just about any color you could imagine (as long as you don't imagine orange.)

Make your own bioplastic

That's just goop.

I guess it's a plastic and all, but it looks like you're making a big blob of snot.

The recipe goes a little something like this...
  • 1 tbsp cornstarch (tapioca starch recommended in the video)
  • 4 tbsp water
  • 1 tsp glycerine
  • 1 tsp vinegar
  • mix while cold
  • heat until thick and snot-toothpaste-like and completely clear (see 1:50 for final product)
  • spread on silicon mat and let cool
Here's another, similar recipe with way more explanation of the science - but a foolishly white background making the mixture almost impossible to see.

How to make Prince Rupert's drops - glass that fractures at the speed of high explosives

NightHawkInFlight doesn't specify which type of glass he's using, but I'm pretty sure it's just soda lime glass (available from Flinn Scientific, at least that's our common source for the summer camps.)

The technique for making Prince Rupert's drops takes a little practice but really isn't all that tough to manage with a little trial and error.

Here's another POV - including a fair bit of the science and where Prince Rupert's drops would fit into a science curriculum.

Artistic Chemistry: a beuatiful collaboration

I'd never heard of Frog Valley before reading the April 2012 Chem Matters article, "Artistic Chemistry: a beautiful collaboration," and to be quite honest, the article didn't exactly tempt me to drive six and a half hours to see an artist collective. As the last paragraph of the article says, "you may want to try raku pottery or stained glass. Classes are offered throughout the United States, and chances are, classes are available near you." 

Apparently there's no reason to go to Frog Valley. Thanks, Helen Herlocker.

The other part of that last paragraph, though, "while you learn about the properties of the materials and how they interact with each other, you will discover that it really is all about chemistry!"

The article covers the science of raku pottery (oxidation, reduction, metals, and metallic oxides) as well as the copper foil method of making stained glass windows (chemical reactions, production of hydrochloric acid, tarnishing of the copper foil).

Plus you get to see some really pretty artwork.

Get out there and take a class this summer, folks. Make a stained glass piece (don't leave it out for your custodian to knock over like I foolishly did with mine). Throw a raku pot. Blow glass.

Learn something.

Make something beautiful.

The afterlife of plastics

In 2003 I read an article titled "Anything Into Oil" from Discover magazine. That article described a process through which effectively all trash (other than heavy metals) was going to be recycled into usable oil of various molecular weights.

That's it, I thought, no more trash. We're done. We've got that whole trash problem licked. All the landfills can be dug back up and run through the Anything-Into-Oil-er machine to make profit. Step two had finally been solved.

Two years later...update... two more years later...another update...

Flash to seven years later than that and I'm still sending my trash to Mount Rumpke.

Along comes "The Afterlife of Plastic" from Al Jazeera in which we get to read about a new plant opened up to turn plastic into oil. Some of the details are simplified a bit...
Plastic is usually made by heating crude oil, cooling it and adding preservatives so it is able to hold its shape. It can then be molded into light, flexible forms for use as shopping bags, takeout containers or plastic toys.
I'm all in favor of the recycling of plastic and keeping microscopic bits out of the oceans and everything, but I've been hearing promised solutions to the intractable problems with plastics for a decade now.

Don't toy with my emotions here, folks.

Thanks, by the way, to Brian Wright for passing this link along.

Pinkbike vists the Santa Cruz Test Lab Video

break it!

Break it!


Joe Graney might want to talk to somebody about how to look like he's actually enjoying his hosting duties, because he's lucky enough to be standing there and breaking the snot out of both aluminum and carbon fiber bike frames (with a screw drive at 0:47 and then with dropped weights at 2:45).

Interestingly, the sudden breaks (from dropped weights) don't look all that different, but the slow breaks look very different.

Thanks, by the way, to Frank Marks, Director of Engineering for Utah Test and Training Range, who showed this at our graduation in Salt Lake City last week.

Allotropes of Iron (a phase diagram)

One of our campers, Michael Martin, in Salt Lake City was searching for a phase diagram for iron while my co-master teacher explained the glory that is the iron wire demonstration. See, phase diagrams are comfortable and familiar for we few, we happy few, we chemistry teachers. 

Luckily, he found a really nice one showing the various allotropes of iron at different temperatures (and at really low pressures.)

Not everybody else looks at a phase diagram as familiar, comfortable territory, but we do, and sometimes it helps to put new information (the crystal changes for iron at increasing temperature) in a familiar form.

Sunday, June 28, 2015

Where to buy ice cube trays & periodic tables

In our summer, teachers camp, we compare the workability of various metals based on their crystal structure, particularly the number of slip planes and amount of empty space ('gappiness') within the crystal.

I won't go all spoiler on you, but I do want to point out where we can get three of the tools that we use in the teaching of that topic.

First, there's the Sargent Welch student periodic table. The reason we particularly like this periodic table is that each square on the table shows the crystal structure (body centered cubic, BCC; face centered cubic, FCC; hexagonal close packed, HCP; etc) that each element takes in its solid form. I like to ask the students (or teachers if it's summer) which metals they already know are workable (usually gold, silver, aluminum, copper). We then check those metals' crystal structures to find them all FCC. From there, it's to the opposite end of the spectrum, to the least workable metals (titanium, cobalt, sometimes magnesium) which turn out to be HCP. (Check out the table in a large, printable form.)

Those periodic tables are available from Sargent Welch in all sorts of formats (8.5" x 11", 11" x 17" - even in French if that's what you need) or as a 50" x 38" poster.

While teaching that same topic, we also use a couple of types of ice cube trays for water bottle ice cubes. The first type of tray has very little empty space between the individual water reservoirs. This relates to the crystals with very little 'gappiness'. These trays can be found from time to time in the summer (sometimes on endcaps at WalMart in the summer, garden section). They can also be found reliably on Amazon, though, and the best deal I've found is a rainbow set of four, two-part trays for $9.99 (as of June 2015, anyway).

The other type of trays have more empty space between the water reservoirs, so they allow us to demonstrate the fact that crystals with more empty space within the slip planes. These tend to be more rigid, more fragile, and less easily found in stores. I don't know if that's because they require more plastic to produce or what, but I do know I haven't been able to find them anywhere in person for a few years. Amazon, however, has a bunch of options to buy them, the best of which gets you four, white plastic trays for $7.99 (again, as of June, 2015).

Where to buy a variac?

The iron wire demonstration is brilliant for showing an application of a solid state phase change, an allatropic phase change, and an real-world application of the idea that different crystal structures do, indeed, affect the properties of a material.

The biggest to that hurdle, however, is finding a way to adjust the AC current traveling through the iron wire, itself. It is possible to do so using very unsafe methods (I've seen it done with a split cord, two copper wires, and a trough of water to which an increasing amount of salt was added, but I do NOT recommend that method), but the best method is a 20-amp variac.

A couple of master teachers swear by the variacs that come from Parts Express, but they're $200, or alltronics, still $170. Recently, however, I found what looks to be the exact, identical variac available for $109 from Circuit Specialists.

Has anybody ever ordered from Circuit Specialists? If so, what was your experience - especially as to the quality of their product?

How to Make Bismuth Crystals

Bisumth has a melting point of - as the video says at 0:20 - 520 degrees F (or about 260 C). That's a temperature easily reached on a stove top without significant investment in special equipment.

In the above video, NightHawkInLight uses a stovetop and a steel pan. That should be achievable in even the smallest science department budgets, and the crystals that are produced are absolutely gorgeous.

You do still have to get some bismuth (may I recommend rotometals?), but then you, too, can be making some gorgeous hopper crystals.

The Sand and the Fury

Our civilization is literally built on sand. People have used it for construction since at least the time of the ancient Egyptians. In the 15th century, an Italian artisan figured out how to turn sand into transparent glass, which made possible the microscopes, telescopes, and other technologies that helped drive the Renaissance’s scientific revolution (also, affordable windows). Sand of various kinds is an essential ingredient in detergents, cosmetics, toothpaste, solar panels, silicon chips, and especially buildings; every concrete structure is basically tons of sand and gravel glued together with cement.
Our appetite for expansion, for building, for creation is nigh on bottomless.

And it seems like our sources of sand for that expansion should also be bottomless. There's the deserts of Africa, Asia, North America - even of Antarctica. Heck, there's enough sand in my swim trunks from my recent trip to the beach (more on that material science connection later). But it turns out that desert sand (weathered by wind) and river sand (weathered by water) aren't even remotely the same when it comes to building. As the Wired article explains, "Desert sand generally doesn’t work for construction; shaped by wind rather than water, desert grains are too round to bind together well."

That leaves us dredging rivers and bays and oceans for more and more sand, diving deeper ("he thinks the river’s sand will soon be mined out. 'When I started, we only had to go down 20 feet,' he says. 'Now it’s 40. We can only dive 50 feet. If it gets much lower, we’ll be out of a job.' ") and evend destroying entire island ("Sand mining has erased at least two dozen Indonesian islands since 2005. The stuff of those islands mostly ended up in Singapore, which needs titanic amounts to continue its program of artificially adding territory by reclaiming land from the sea. The city-state has created an extra 130 square kilometers in the past 40 years and is still adding more, making it by far the world’s largest sand importer.")

We need to, as always, remember that building is a zero-sum game. Everything that goes up has to come from somewhere.

And often, there are huge environmental and human costs in getting that materials from that somewhere.

Thursday, June 18, 2015

Alcohol Raku Firing of a copper matte glaze with alcohol reduction

I am seriously terrified by the use of alcohol as the combustible material for the raku process. I've posted a video and said as much before, but there's a reason for this post beyond just the use of alcohol as the combustible material and the lack of proper safety equipment (no safety goggles, shorts, Crocs). It's the explanation that appears at 0:58 in the video:
The hottest spots will color up first, so be ready to spray water on spots you want to color freeze. Torch the copper colored areas later and spray water when you hit the desired color [to] freeze it. If you mess up, you can always refire and try again!
Ok, on some level I've understood that the reduction of the metal oxides is favorable at high temperatures (we discuss that in AP chemistry as it relates to thermodynamics and Gibbs free energy, and we show it in material science when we demonstrate the copper sheet), and I even knew that the process was reversible because of that demonstration. I never thought to apply that to raku, however.

The reduction in raku happens best with the first few pieces pulled from the kiln because they're the hottest ones. The cooler ones are on the verge of being too cool for the reduction to take place. That's shown in the rainbow of oxidation that appears at 2:47. The oxidation builds back as the piece cools until the glaze is cool enough to lock the color in and not allow any more oxygen into the metal/metal oxide system. There's a sweet spot of temperature above which reduction happens, below which the glaze is set and neither oxidation or reduction can happen, and during which oxidation can happen.

But I never thought to 'refire' the pieces using a torch (5:40)...or to use a spray bottle to quick cool the piece below that magic range and lock in the color (2:40)....or to display my raku pieces in a drained hot tube (6:47).

That's brilliant in its simplicity.

As we hear at 1:48, "it's almost like a science."

Crystal growing kits (like teacher camp activities)

I really like that nearly perfect cube of NaCl (Does anybody know why would you need KCl in the solution?) I may make that a task from one of my student aides this year.

Or I may try a few different crystals that come in a crystal growing kit (item 15114) from Flinn Scientific.

Every year in our material science course, the students grow copper (II) sulfate crystals, so I'm familiar with the pretty blue crystals (shown above in the video, too), but I haven't tried the other chemicals (alum, chrome alum, nickel sulfate, and sodium chlorate) that come in the kit and which, I assume, grow via the same procedure. I should know what they look like and will post photos after this year.

Yes, I'm quasi-endorsing the purchase of a Flinn lab kit (though not this one). They're a nice way to get and try a lab once, but I will fully endorse buying the resupply chemicals separately because the kits are always more expensive than the raw materials.

Rocket Under Ice

In general, I wouldn't post anything this stupid (there are exceptions, natch), but the shattering of the ice from the underwater bottle rocket explosion is just so darn hexagonal, breaking as it does, I assume, because of ice's hexagonal crystal structure.

Researchers build aluminum battery that can be charged in one minute

The aluminum-graphite battery being displayed in the video (and in the post) sounds a little too good to be true. It's flexible, safe even if drilled, rechargeable in minutes, made of environmentally safe materials, and theoretically cheap.

I assume somehow it'll be found to kill puppies every time your recharge it.

Something has to be wrong with a battery like that, right?

Sculpting with polyurethane foam

We're big fans of Flinn Scientific.

By we I mean the teachers of the summer teacher camps because Flinn cuts us a slight discount with our ordering for the camps, but I've been a Flinn fan for far longer than my involvement in the ASM program. Flinn is a company that provides outstanding service to teachers, offering free workshops on safety and teaching around the country as well as at NSTA and ACS conferences.

Ok, enough gushing, to the material science stuff.

The two-part foams that we use in our summer workshops actually comes from IASCO (the flexible foam is FF-5Q and the rigid foam is RF-4CFCQ in their catalog), but Flinn does sell the rigid foam as C0335.

The video above is neat because it shows the more artsy applications, turning the foam into cute creatures with the addition of googly eyes and pipe cleaners. I also like the giant tower of foam that's behind the presenter. Anybody wanna make me one of those?

Monday, June 1, 2015

Shattering the Shatterproof

That just seems wasteful, destroying a spark plug like that. I mean a spark plug for my car is a whole seven or eight or even nine dollars.

The tinting on the windows, though, that's pretty cool.

I dig the simplicity of the sharp points of the shattered ceramic of the spark plug breaking the heck out of the tempered glass. The use of the big, wide-headed, rubber hammer is hokey, though, because it's about as un-sharp and pointy as it could be. It's a bit of cheating there, and it doesn't really work as an initial hammering for me.