The secret of the aluminum can: what is it hiding?

That's some impressive can polishing right there.

This video from MEL Chemistry shows how to reveal the secret polymer liner that lives inside every pop can (or Coke can if you're from Southern Indiana like your friendly neighborhood blogger is) using 'drain cleaner.' I assume it's something like Drano, a very concentrated solution of primarily sodium hydroxide. 

I do this experiment in class using hydrochloric acid in the 3M range, and it works just fine. Aluminum is, however, soluble in both acids and bases (not typical of most metals), so I have heard that sodium hydroxide solutions can produce the same result. 

I would certainly be careful with the 'drain cleaner', folks, because it's some nasty stuff. Weirdly, I'm more comfortable using 3M HCl because it's something I use with fair regularity at school. The Drano, however, gives me a bit of an uneasy feeling. Oddly, though, Steve Spangler's video of the same demo also uses sodium hydroxide as did most of the other videos I found showing this demonstration. That might be because buying hydrochloric acid can be a bit tougher (unless you know it's also called muriatic acid and is available at most hardware stores.)

Either way, be careful if you try this at home, but it's pretty frickin' awesome to see.

Green materials for a greener world: Athanassia Athanassiou at TEDxRoma

Ah, TED in Rome...discussions of pizza and gelato, gladiators and forums, Catholicism and plastics...

You know, plastics. The worst thing that we've done for our environment and that we keep using more of every day.

This video opens with an enumeration of the environmental horrors of plastics - volatile gas releases, effects on our hormones, increasing petroleum needs, oil spills and seeps, toxic discharges into the environment - and shifts to alternate options to our uses of polymers.

The speaker, Athanassia Athanassiou (seriously, that's what the title says), illustrates some of the polymer replacements or adaptations that her research group is working on to either modify polymers to actually help the environment or to replace the polymers with other materials.

The video is more a survey of some research than it is an inspirational TED talk. Neat ideas, though.

(As an aside, why would the foreign TEDx conferences be presenting in English? None of the TEDx conferences in America are in foreign languages. Just wondering...)

My YouTube subscriptions

In case you were wondering which science- or material science-themed YouTube channels I subscribed to, you could probably just skim back through and see which video sources I post from most frequently.

But I thought I could put together a list in case you wanted to subscribe to them, too. So, in no particular order...

• Smarter Every Day - Hands down, my favorite channel on YouTube. Destin Sandlin is an engineer turned YouTuber who covers a whole host of science topics both high brow - How Do We Land on the Moon - to low brow - How Do You Harvest Pecans - and covers them all with a humility, curiosity, and ease of communication that is infectious. Occasionally he gets a little too excited about things (check his collaborations with Mark Robert, for example), but most of the time his tone is spot on, and I learn something from nearly every video that he makes. Most tend to be ten to twenty minutes, but occasionally he post forty-five minute to an hour videos and takes a far deeper dive into a topic - take his nuclear sub series, for example. You could easily turn his videos into a year-long science course. I'd take it. He also has a second channel of slightly less polished videos and lots of behind the scenes footage. Destin also spoke at Skepticon about balancing his faith and his science. It's a great talk. His TED talk isn't bad, either. (equally for both blogs)
  
  
• Real Engineering - Initially this channel from Brian James McManus (yes, he's Irish) focused mostly on the rudiments and basics of engineering and used a lot of white on blueprint paper background animation. He's upped his video quality and started using a whole lot more licensed footage over the years, and he now tackles some pretty deep dives into engineering topics (solar panels, renewably powered ships, tesla's battery challenges, colonizing the moon, digital vs vinyl sound, etc). Videos tend to be in the 15-25 minute range anymore. We almost never see Brian, himself, though there have been a couple of videos where we did. I learn a TON from his videos at this point. Initially, I didn't learn nearly as much. (more for MatSci blog)
  
  
• Practical Engineering - Grady Hillhouse reports from his house in San Antonio and makes civil and mechanical engineering incredibly understandable. Some of the best parts in his videos are his small-scale, homemade demonstration aids to help him explain the video's concepts. He's built tiny rivers to show how weirs function, made rebar-reinforced concrete cylinders to show how they improve concrete's resistance to cracking, crafted complex pipe systems to show water hammer, and much more. His videos stick to the 8-12 minute range, and are great explanations of basic engineering concepts. (more for MatSci blog)
  
  
• Veritasium -  Dr Derek Muller hosts - and probably writes - the veritasium channel videos. He originally did all the work himself, but one of his more recent videos celebrating his tenth anniversary on YouTube talked a bit about his increasing team helping him make videos of higher and higher quality. Muller comes out of Canada by way of Australia and is all over the map as far as topics go. His videos are about optical illusions, origami engineering, calculating the speed of light, close packing with shade balls, and - my absolute favorite video of his - how trees get their mass. He covers chemistry, biology, engineering, physics, and general philosophy of science. (equally for both blogs)

• Steve Mould - Steve's videos are far less focused on any one area of science (or of math). He covers everything from "I calculated absolute zero with vodka" to "Tree tumors are GMOs but not made by humans" to "Self driving cars are dangerously confused by LED lights" to "Does Canadian money really smell like maple syrup?". He's a bit of all over the place, in other words, wandering pretty much anywhere that his curiosity happens to take him. The initial videos were pretty low-budget and short (1-4 minutes long), but the quality of video made a pretty big jump about five years ago. The videos have gotten longer over time, some of them wandering to the fifteen minute range, though he still makes a decent number of videos that are in four or five minutes long or shorter. (equally for both blogs)
  
  
• Mark Rober - Mark's all about building bigger, more theatrical versions of everyday things. He's build a scaled up SuperSoaker, filled a pool with jello, and set up the world's largest elephant toothpaste (or devil's toothpaste). He's also built machines to skip stones better than humanly possible, squirrel obstacle courses, and a liquid sand hot tub. Admittedly, most of his videos could be cut by about 25% of their length by eliminating the over-reaction shots. I think his best videos are the most focused. I particularly recommend the rock skipping video.

AMP Recycling Robots

I desperately want recycling to work.

The more I read about recycling in the US, the more I just want to cry. 

Whether it's NPR's report on how little plastic gets recycled and how the plastics industry developed recycling codes to make us feel better about using their products, a video on the un-recyclableness of black plastics, or the last twenty years dashing my hopes from turning "Anything Into Oil", I find myself hopeless and lost whenever I think of the magnitude of our plastics problem, and I fear that recycling - at least as it is right now - isn't the solution.

And then along comes the AMP sorting robot (an article about them), and they pull me right back in.

Mystery blue & white beads

The blue and white bead bottle up there might look familiar to a lot of science teachers, especially the ones who have taken our ASM summer camps. The bottle can be bought from Educational Innovations or from Flinn Scientific (though Flinn's version is green and white).

The bottle is a spectacular demonstration of density and of solubility, both of which are explained by Steve Mould in the above video.

We do a similar activity in a lab in our material science course at Princeton (one we certainly didn't develop but have tweeked to our needs) using preforms and polymer pellets. An extension we particularly like is related to the food coloring demo that Mould mentions in passing near the end. I especially recommend green food coloring. The effects are far more dramatic than the red that Mould shows.

Another extension involves shining ultraviolet light at the bottle. It turns out that - as one of our Utah campers pointed out to me after I'd had the bottle for a decade or so - that the white beads are actually the UV beads that Ed Inn sells. Apparently having a classroom with no windows blocked me from seeing that happen until she pointed it out to me.

I did also find a video showing how you can make one of your own - without the UV beads, however. The YouTuber's full instructions with quantities can be found in the video description.

I'll copy the video description, however, in case the video experiences link rot...

"Sorry for the spelling mistake in one sentence!

Water and Isopropyl alcohol are SOLUBLE with each other. (solvable is wrong word)

Poly Density Bottle

Take any size bottle, divide number of ounces of the bottle into half. Half number of ounces distilled water and half number of ounces 91% Isopropyl alcohol.

I used 50oz bottle.

So I added 23oz water and 23oz Isopropyl alcohol.

Salt 1tsp for 1oz of water.

So I mixed 23tsps of Salt in water.

Not filling the bottle completely and leaving some space for air at the top is a good idea.

Easy to shake and mix liquids.

Beads 260 of each kind.

You can add or minus number of beads according to the size of the bottle."

This mushroom brick could replace concrete

Cement sucks.

It's pretty bad for the environment on the front end as its production releases a whole bunch of carbon dioxide into the air, and it's not great on the back end because large swaths of pavement deny water's opportunities to get back into the ground, increasing runoff that is frequently polluted.

I've posted about mycelium materials before, but I particularly like this video's combination of a bit of pro-forest coverage and the fact that the reporter made her own 'mushroom' brick.

That might have to be a project for next year.

Three-point bend test fixture - with plans

3 Point Bend Test Report by phschemguy on Scribd

In the spring of 2015, Bob Hanlin, one of the ASM master teachers and a professor at University of Missouri-Kansas City, came to our spring training with a project that some of his students had developed. It was a three-point beam tester made on the cheap and designed to be cheaply made by high school teachers to more accurately and repeatedly test the cement composite beams that we make as part of the material science curriculum.

Bob had tasked his students with the following requirements, as found on page three of their final report - embedded above...

• Repeatable testing
• The new fixture and method of breaking the cement has to be able to be repeatable and provide similar results.
• Portable
• The fixture has to be compact and easy to transport since high school teachers will have to take the fixture to school and carry it around.
• Accurate
• The testing mechanism hast o prove similar test results when in use.
• Easy to make
• The new fixture design has to be simple and easy to make since high school teacher[s] will be building it to teach the students the importance of material science.
• Inexpensive
• The fixture has to be as low-cost as reasonably achievable since high school teachers have to function on a meager budget and sometimes [are] forced to spend their own money out-of-pocket.

Man, that's a set of requirements that screams understanding of the high school science/engineering teacher world. Cheap, easy to make, portable (storable, too), accurate, and repeatable...that's pretty spot on perfect for our world.

Bob showed off his students' creation at the training, and we were all amazed at the results. No, it's not a commercial beam tester, and the accuracy doesn't approach that level of precision and repeatability, but for $30, it's a brilliant bit of engineering.

I finally got permission from Bob (who actually had to get permission from the university) to publish the tester's plans here on my blog. The one stipulation was that credit had to be given to the students - Gabriella Baptistella, Zach Kellogg, Vincent Nolan, and Lee Seela - and to the University of Missouri-Kansas City. I'm happy to credit all of those folks because their product is just brilliant.

The students explored two fixtures and two methods of testing for each fixture. In the end, the best choice is the one they labeled fixture 2 - method 3. The exact plans for 2-3 can be found in the embedded document above in appendix B (p17). The fish scale that Bob used when he showed us was - I think - this one from Amazon. Everything else would be a Home Depot/Lowe's/local hardware store purchase.

Here are pics of the final product - along with Bob in the dark blue plaid.

 

By the way, in explaining how he'd gotten students to help design the tester, Bob mentioned that the funds for the design project came from the tuition that our ASM summer camp teachers have been paying for grad hours related to the teacher summer camps over the past few years. So it you - like I - have taken the grad hours, thank you for your contribution to this project.

So, go, make yourself some beams and get to testing them.

Oh, and if you want to see our old method for testing the beams, here's a pic from the UMKC website showing our pre-these-plans method from their ASM teacher summer camp.

Source - UMKC website