Costa Rica's Turquoise River - A Natural Optical Illusion

That blue water doesn't look too natural to me.

I mean it's a gorgeous blue, but it's a blue that doesn't seem quite right.

Apparently - at least according to this article - there's no copper in the water, so that's not what it's blue.

Instead, the Rio Celeste produces particulates of aluimosilicate of exactly the right size to reflect light in the blue area of the spectrum. Neither tributary contains particles of the right size, but...

[t]here was only one puzzle left to solve, though. If Rio Buena Vista also had an abundance of aluminosilicate, how come its water looked completely transparent, while Rio Celeste appeared to be turquoise? It turned out to be a matter of particle size. Upon analyzing samples from both bodies of water, scientists realized that aluminosilicate particles in Rio Buena Vista measured 184 nanometers (nm), while those in Rio Celeste were much larger at 566 nm

“This increase in size is what causes the scattering of sunlight, such that it occurs principally in the blue region of the visible spectrum. So that’s why we have that spectacular light blue color of the Rio Celeste” said Dr. Max Chavarría Vargas, who lead the scientific investigation into the turquoise waters of Rio Celeste. “It’s one of those quirks of nature where one of the rivers provides mineral material with one size and the other river provides the acidic environment so that those particles grow.”

Who knew that particulate size mattered?

Brad Makes a Knife with Bob Kramer | It's Alive | Bon Appétit

I'm a fan of goofy Brad, the host of the video series, It's Alive. Mostly the show is about cooking in the realm of fermented foods (kombucha, beer, garlic honey, cultured butter, sauerkraut, etc), but this time Brad goes to a small-scale knife shop because, as he says at about 13:10, "this ain't necessarily alive, but it's got energy...watching [the knife-making process] from start to finish, if it don't make you feel alive, I can't help you.

There are a bunch of metal topics covered here...

• 0:45 - "make some steel from scratch"...they make their steel from powdered ingredients (carbon, iron, manganese) and then melt them together
• 1:30 - induction heat melting of the steel ingredients
• 2:20 (and again at 3:00) - forging...the take the fresh, steel 'biscuit', reheat it 
• 2:45 - heating the steel back up to the plastic state...they don't mention the phase transition from BCC to FCC, but they do explain that hot steel can change it shape more easily...and that they have to reheat the 'biscuit' because it's getting cold
• 3:30 - rolling mill...a small mill but still far larger than what we show in the summer workshop
• 4:15 - forge welding different steels together...they only refer to the steels as steel A and steel B...no mention of high- or low-carbon steels
• 4:40 - iron oxide...the captions explain that, "[t]hose dark flakes are iron oxide. High temperatures accelerate the oxidation process."
• 6:20 - "quench tank there, Vinnie"...Vinnie is the camera man for all the Bon Appétit videos...no explanation yet as to why you would quench something
• 6:58 - hardening the knife...molten salt bath for an oxygen-free atmosphere for heating..."dissolving the carbon into the iron" then capturing it during the quench...followed by a tempering bath to, "bring the knife to a working hardness, so it's not too hard...not too brittle"..."when it's hardened, it's under a lot of STRESS...we go in there (the tempering bath) and it just adds some heat, kind of massages it...makes the knife 'happy'...yeah, this is the 'martini' for the knife"...there's a decent graphic summary of this at 7:50
• 8:40 - acid etching the knife..."the acid eats these layers at a different rate...because we mixed in different things in the steel"
• 11:20 - nothing curricular, but watching Bob Kramer put a blade on the knife just by eye as stunning...I assume it took a few more passes than what the video shows, but he makes it look so casual and awesome...I'm amazed

Warnings

• 7:35 - mention of making the steel happy via a 'martini'
• 10:20 - there's a bleeped, "I always f*#^ that up"

Brad's a goof, but it's loads of fun to watch him make a knife.

Prop: Shop - How to Make a Vacuum Forming Machine

This might be a little beyond my skill set at this point, but with the shift of material science from a semester to a full year, this might be in the future.

Gonna need myself a little suctioned viking head.

Phase Transition in Steel

That's an interesting addition to the iron wire demo: a glass rod to exaggerate the 'dip'.

The glass rod makes sense because it's non-conductive enough to not be too dangerous, I would think.

The graphing on the video really makes the phase transitions remarkably visible, though.

I like it.

The video's description gives a little more detail as well as the reason for the slow, overall downward slope.

A steel wire is heated up by a current and it expands. When the phase transition temperature is reached the wire takes up additional energy which cools the wire down for a short time and shortens it. 

This step can also be observed in the opposite direction when the current is switched off and the wire cools down. When the phase transition takes place the wire is heated up and it expands for a short time. 

Over three cycles the thin wire gets already worn out. Is is deformed so that the diameter, the heating power and the temperature is not equal along the wire and the phase change occurs more distributed over time.

Heat treating tool steel -- the phase change

I'm going to trust the video's description (copied below) when it says that the flashes of light at 0:32 are visual indications of the BCC --> FCC phase change that takes place at 910 C.

Visual indication of tool steel phase change to austenite when heat treating. Small pools of iron are forced from the steel as the volumetric change takes place and small amounts of carbon are burned off.

So, my understanding from reading that, is that the BCC (ferrite) --> FCC (austenite) change squeezes some of the carbon out of the structure. That carbon then - because of the high temp and the presence of oxygen around the steel - burns off in the flashes that we see.

Can anybody tell me that I'm reading the situation correctly?

The Coolest Way to Open a Bottle of Wine

Yeah, that's one way to open a bottle of wine.

Shatter the glass, yeah.

It causes some secondary challenges (possible shards of glass in the wine, a messy lip of broken glass), all of which seem to have brought about solutions to those challenges.

As neat as the science is (hot glass contracts quickly and unevenly when cooled suddenly, aka thermal shock), the whole process just seems needlessly Rube Goldbergian to me.

High-paying jobs for people who don't like stress

I'm not sure that I agree with this "24 High-Paying Jobs for People who Don't Like Stress" article.

They list material scientist as being the #1 most stress-free high paying job.

All the material scientists I know seem to always be talking about stress...and strain.

(In all seriousness, as I type this at the end of the quarter and think about all the grading I'm behind on finishing and the letters of recommendation I need to write and the National Honor Society applications I need to evaluate, I'm thinking I might've steered down a less stressful, higher paying career path if I'd known about material science back in high school.)

ASM Summer Camps - 2017

The summer ASM teacher camp schedule is up and posted on the ASM Foundation website - link here.

The teachers camps - in case you weren't aware, and the majority of you folks visiting here are probably familiar if not intimately so - are phenomenal. Check out the testimonials and news reports from the camps here.

Railroad Thermite Welding: Europe & Russia

(Edit: As of 6/28/21, the old video had disappeared from YouTube, and I wasn't able to find it anywhere. I was able to find the animation, however, and since that's the only really important thing, I'm reposting that video. If you want to find videos of railroad welding, I have others of that, too.)

Yup, dramatic music at the beginning. That's...um...awesome?

In addition to possibly watching this with the sound off, I'd also suggest turning off the annotations because they're just annoying ads for other videos.

There's a pretty stunning, handheld blowtorch at 0:30. All those tiny flames makes me wonder just how frickin' hot the torch gets.

Most of what we get in the video - including the phenomenally bright fire at 1:55 - is pretty standard railroad, thermite welding.

The animation at 2:09, however, isn't standard. It's a great cutout view of what's happening within the thermite weld.

After that, there isn't much more than three barely  different versions of thermite welding. The first ends around 3:05. The second ends around 5:50, and the third wraps up at about 8:25.

Really, the animation at 2:09 is the only new thing to see here.

The History of Iron and Steel

I'll be right back. I'm going to refresh myself with the video Material Properties 101 before I watch the rest of this. Luckily, your friendly neighborhood blogger already linked to that video, too.

The video is a great exploration of...

• the differences between wrought iron, steel, and cast iron
• the processes in purifying iron ore - especially highlighting other videos that show primitive ways of doing this in modern times
• blast furnaces, used to purify iron ore in modern times
• producing steel in various ways - including via a puddling furnace
• the Bessemer converter to produce steel

The video is, I think, too long to show in class unless your students have a better attention span - and tolerance for foreign accents - than mine do.

The video shows that it's 13:35 long, but it's really about ten minutes followed by a plea for a charity donation for the last three and a half minutes. The charity donation link is no longer accepting donations.

At 2:38 there's a hiccup in language. He says wrought iron is less than 0.8% carbon, but his graphic shows that it's less than 0.08% carbon. Wikipedia agrees with his graphic. Decimal places are hard sometimes.

Alcohol Reducation Raku with Shawn Felts

Raku is pretty stunning.

I don't know that we need another raku video on this blog, admittedly, but there's something unique here that's worth seeing.

• I very much dig that the video here opens with a comment that Shawn Felts worked at Funke's Fired Arts (the ceramics store here in Cincy that we use for our supplies at Princeton HS). They've changed ownership and names since Shawn worked there, but they're still a good place.
• There's a whole lot of talking to start the video meaning it's really informative, but it would be awful to show in class. There's no way that students are going to pay attention until probably 19 minutes in - when the fire starts.
• I appreciate the full beard and the confidence with it around the fire.
• At about 13:40 he mentions that raku pottery all fades to black (oxidized) over time. I've not noticed that in the past, though I've only done raku for about a half dozen years. Is that fading anything that anybody has seen in their experience? I think our glazes might encase the reduced metal in a thicker glass layer, so that may not be the case for our process.
• Holy crap that furnace ramps quickly. He goes from room temp to 1750 F in about twenty minutes. That's a fast, frickin' ramp rate.
• So much of this seems like he's doing it because he's done it before and it worked. Comments like that the alcohol 'soaks into' the glaze make me think that the science is a little iffy in some of his explanations.
• It's at about 18:50 that the piece finally comes out of the kiln. 
• I'm still very much unsure of how the glazes work and all the science of raku. With my understanding of the science, the repeated sprays of alcohol are doing almost nothing because it's just burning off each time. Yes, oxygen is being used up and copper is reducing, but that is immediately lost when the hot pot is allowed to then sit in the air before being moved into the sand under the glass bowl.
• The glass bowl is the big reason why I'm posting this video. We actually get to see the reduction (at 21:15 with the last shot of alcohol into the reduction chamber), something that we never get to see because our reduction chamber is entirely opaque (metal paint cans.)
• I appreciate Shawn's impatience, something he mentions at 25.45...and again at 28:05.
• I wonder how much the time jumped at 24:15, because there's a clear edit. How long was the piece in the reduction chamber cooling down?  
• Can we talk Bernoulli's Principle when he blows the air in at 24:44?
• Holy crap...the color change right after the blow of air is a great money shot for the video. Actually seeing the reduced copper (shiny penny) change to oxidized copper (shiny blue, purple, green) is stunning.
• Does the spray with water just cool the glaze enough to not allow oxygen to move into or out of the glaze? That's my understanding but doesn't quite fit with Shawn's explanation.
• More edits at 26:14...27:30...30:35...31:35
• Who are the people watching this video? They don't look like they're dressed to get involved. Maybe this is just an open house situation.
• I never knew what grog was (28:40). I knew our raku clay had a bunch, and I kind of knew why (decrease thermal shock). I just never knew what grog was - already fired, pulverized clay so it doesn't shrink. 
• Shawn mentions at 28:50 that he could dunk the raku piece in water without it shocking but almost chuckles as if he wouldn't want to risk it. Hey, that's exactly what we do with our pieces.
• Some alcohol jokes at 30:10 - talks about the fumes tasting like rubbing alcohol and that Shawn's more a bourbon man than he is a rubbing alcohol man.

Shear Pins are Smart (They're Mechanical Fuses)

I'm not a car guy.

I'm even less of a tractor guy.

I pay to get my oil changed, and I'm happy to do it.

So, when it came up in our summer camp discussions that quenched metal would be useful for shear pins, I wasn't really comfortable with doing more than just nodding and smiling. "Yeah, shear pins...exactly."

Then I had to go look up what shear pins are.

Now, here's my understanding. Shear pins are hardened steel, typically quenched steel. Sometimes a rotational part of the machine - the lawnmower blade, the snow-blower - gets blocked and stopped. There's a driveshaft feeding rotational energy to that blade, however. Something in the chain  then has to break because the motor is continuing to try adding more rotational energy to the now-stuck blade.

If all the parts were equally tough, the break would take place randomly.

Instead, the engineers intentionally put in a weak spot, a quenched piece of metal called a shear pin. The intent is for that piece to be where the break happens because it's the cheapest part of the chain. It's better to break the cheap part than to maybe break one of the expensive parts.

Man, it's almost like people are smart.

I'm happy to say that I'm getting smarter every day.

Solid-Liquid Phase Diagrams: salt solution

Trigger warning: One of the linked articles addresses tie lines.

In our summer workshops we have a demonstration (amateurishly filmed versions can be seen here and here) that is designed to show and introduce the idea of a eutectic point, the mixture of two pure substances that has the lowest possible melting point.

In the workshops, we use either a tin-bismuth or lead-bismuth mixture. The teacher campers produce 'spots' in varying alloy compositions from 100% tin to 100% bismuth. We then melt the spots on a pancake griddle and produce a eutectic graph.

All of that is explained brilliantly on this page (for the lead-tin mixture). In our summer workshop, we don't remotely address tie lines, through which the exact composition (what % of the liquid is tin versus lead) of the 'slushy' mixture can be determined. That's beyond the scope of the summer workshop, but it's highly relevant for metallurgists.

One of my campers a couple of years ago, however, brought up the connection of the bismuth-tin eutectic to the mixture of salt and water, a mixture of which melts at a lower temperature than does either pure substance. At the time, I acknowledged that this was exactly the same idea and moved on.

Since then, however, I hunted down a salt-water graph similar to that for the bismuth-tin mixture.

Lo and behold, such a graph exists, and there's even a similar article addressing how this is, indeed, like the lead-tin/bismuth-tin eutectic.

It's just the same graph as the one at the top of this article...

I'm so very happy to have found that.

Seriously...I actually am.

Why are you looking at me like that?

I'm nerdy like that.

40 Cool Things to 3D Print That are Actually Useful

That actually does look useful - maybe not for a classroom setting but for an office setting.

It's one of the 50 Cool Things to 3D Print Which Are Actually Useful, each of which links to the plans.

Get printing, folks.

But don't ask for tea from your drink printer.

How Glass is Made

In general, the production of stuff is pretty awesome to watch.

The act of sand becoming glass, however, is just a miracle.

I really like this video because it starts with sand in silos and follows the process through the furnaces - with very, very slow melting - onto liquid tin and onward through the annealing oven.

• Along the way (at 4:35, to be specific), we get to see how flexible the still-hot-but-solid glass is.
• Please tell me, though, that at 0:55 he didn't call sodium carbonate and calcium carbonate elements. Maybe he just means 'ingredients' not truly 'elements.'  Language matters, dude.
• At 5:15, they 'haul glass'...it's a funny, doncha see, boy, a funny...
• They show off some fashionable kelvar suits at 5:35 to - as they say at 5:50 - protect your...uh...leg areas.

You can see an animation of the process after the jump...

Making Marbles

I'd been told that marbles were made using shaker tables to round the blobbed, swirled glass 'drops' into spheres. So I went hunting for a video to see that.

That clearly is not how this company makes their marbles.

Instead, this looks to be some sort of screw drive processing as the glass cools followed by a really long run to - I assume - keep the marbles round while they're cooling further.

If anybody finds a marble production video using the shaker table method, please share it.

DEMO KIT 11 01 2013

If you're ever wondering what to get your friendly neighborhood Materials Witness blogger for his birthday (April 28th if you were curious), a demo kit of d3o would be the perfect gift.

Sadly, I haven't been able to find one on ebay, and the d3o website is less than helpful toward educators and students...

Due to an extremely high number of enquiries, we are unable to respond to requests from students, schools, or universities. We are also unable to supply samples of any D3O materials (or “goo”).

A bunch of d3o videos

I haven't the foggiest idea what you need to do to be safe on a motorcycle. I guess my first step would be to not get on the motorcycle, but that's your call.

The above video goes through the advantages and disadvantages of the various materials used to provide protection in a motorcycle jacket: silicon (1:09), thermoplastics (1:40 - though the description of thermoplastics leaves something to be desired), foam (2:32), and viscoelastic materials (3:27) like d3o (SAS Tec, TFArmor, APS Air [though I think that's basically an airbag]- other brands he mentions).

The host's description of d3o is, however, outstanding. He does mention 'grade three' which is a giveaway that he's Canadian.

Markus Kayser - Solar Sinter Project

This doesn't look quite ready for prime time just yet, more of an art project/proof of concept stage for now, but...

The concept of 3d printing using sand (assumedly very pure sand, maybe not the stuff that's surrounding the 3d printer in the open desert) is pretty outstanding there, and the bowl looks awesome.

Mostly similar video but with slightly different edit after the jump...

Robotic ray is part animal, part machine

Frankenstein, here we come.

Or Frankenstein's monster if you'd rather.

Or just Frankenstein if you really want to be pedantic.

I caught this video from the Science journal article that goes into more detail than does the above, silent film video (sadly lacking a mustache twirling badguy). In all honesty, the idea of tuning heart cells to contract in response to light stimulus - which is then designed to create waves of motion within the 'string ray' - is pretty phenomenal.

Making Materials That Heal Themselves

I'm thinking we don't need more sciency-people wearing button-down, plaid, short-sleeve shirts. That's sort of like a dorky stereotype there.

Am I wrong?

One of the common drawbacks of polymers that I always mention in class is that they can't be easily repaired. Maybe someday I'll be able to stop saying that.

Forged in Fire: Bladesmithing 101: The Quench | History

"Fighting the Dragon"?

In our summer materials camp, we heat treat steel (bobby pins and paper clips) including quenching them in water. For the work we're doing, quenching in water works just fine. The mass of the materials is tiny. We're not looking for precise, perfectly repeatable work and products. Water's all good...

But there are a lot of other options for quenching materials. There's air quenching, noble gas quenching, salt quenching, oil quenching, quenching your thirst, quenching your curiosity, quenching in quince.

Wait, those last few aren't really anything with material science.

NOVA's Secret Life of Scientists and Enginners

I'm not entirely sure why BB-8 is in the center of NOVA's banner photo. I'm assuming that somehow Lucasfilms is endorsing the need to make our scientists and engineers look cool.

That's kind of where NOVA's The Secret Life of Scientists and Engineers Facebook page is doing. They post daily news and reports about what scientists do. It's sort of like an ongoing This is What a Scientists Looks Like campaign but a little more professionally done.

Here are a few examples - most of which are available on their YouTube channel...

Toxic Vanity & Fatal Beauty

Eleanor Ryder has two gorgeous photos posted on the National Geographic's website.

The first one, shown above but in much higher resolution on the NatGeo site, is titled Fatal Beauty. Here's what she has to say about it...

A magnification of plastic particles in lip-gloss. The irony of the image is in its intrinsic contradiction; that a product coveted for its ability to beautify is also capable of illimitable harm. The transient nature of a beauty product, once released unbounded in to the marine environment, has the ability to cause infinite damage and contamination. As we lick the gloss from our lips and ingest it, particles enter the sewerage systems to infest our oceans at every level.

The other photo is titled Toxic Vanity and shows similar particles in eyeliner.

Ryder's website has further photos from her Forever Project,

The Forever Project is a portfolio of images focusing on marine debris and micro-plastics. 

Being in my final year of university I wanted to study something I was passionate about and marine welfare is set deep within my heart. 

The images of nano plastics in the Forever Project are a study of the uneasy dichotomy which I feel exists between beauty and marine pollution. These images of micro and nano plastics in cosmetics explores the transient nature of beauty products and their ability to impact upon and do illimitable harm to the marine environment.

I'm thinking we might want to use a little less plastic or make sure it'll actually degrade in something approaching a human lifetime.

What Captain America Can Teach Us About Science

It was my understanding that Cap's shield was made entirely of vibranium, but I guess it's a vibranium/steel alloy.

I appreciate that Dr Mathaudhu doesn't go into the fictional element vibranium's history and existence. Instead he just mentions that a 'mystery element' falls into the experiment and solidifies into what would later become Cap's shield.

Mathaudhu then goes into the connection that he "seeks to design materials that can live in these extremes" - just like Cap's shield. He mentions the switch from a steel to an aluminum alloy in the F150 frame.

He also explains that if a material scientist creates an awesome material but can't reproduce it - like the creator of Cap's shield did - then that wouldn't be a very successful material scientist.

The shield, by the way, is not quite unbreakable in the Marvel universes, but it's certainly a scientific marvel.

Adding A Funny Form Of Carbon To Silly Putty Creates A Heart Monitor

Silly putty is apparently miraculous.

It doesn't walk down stairs - along or in pairs. It doesn't roll over your neighbor's dog.

But it does appear to be usable as a pressure sensor when graphene is added to it. The graphene turns the silly putty into a conductive mass, the precise conductivity of which is highly sensitive to changes in pressure - to the point where it can be used to monitor the blood pressure and pulse in the carotid artery.

Source - NPR and Science

Indestructible Coating?!

If it impresses Dr Derek, then it impresses me.

I've shown you Line-X before, but I wasn't able to show you the science between the two components of Line-X before. In this video, we get to see modeling of the polymerization at 2:00 using plastic, molecular models (by the way, does anybody know the specific plastic model set that they show up close at 3:34? I really dig that set and wouldn't mind getting my hands on a set to see if they're worth buying.)

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).

Snapping a Steel Rod 1000x slower - The Slow Mo Guys

The...

slow...

mo...

guys...

do some neat stuff, and they at least explain some of the science of what's happening along the way...usually...

Just so you know, the actual break happens around 2:30.

We don't actually get much of a science explanation this time, though.

But we do get the braking of a like one (or maybe two-)-inch-diameter rebar rod.

This gel stops bleeding in seconds

Oh, by the way, the video above shows blood.

You know, in case you were queasy about blood or anything...

There are going to be a couple of other blood-centric videos after the jump in a few lines.

The idea that a seventeen-year-old student took algae and developed a blood-stopping polymer makes me think I should probably be doing labs a little more involved with my chemistry students. Sheesh...

Honestly, though, the video up above shows the gel as vetigel, but it's now available as traumagel.

King Tutankhamun's Dagger Was Literally Out Of This World

"That’s right: King Tut had a space dagger."

How cool is that?

An article published in May in the journal Meteoritics and Space Science is titled "The meteoritic origin of Tutankhamun's iron dagger blade".

In the article (sadly behind a paywall but detailed at IFLScience) scientists recount the process of using x-ray fluoroscopy to determine the precise elemental composition of the dagger's blade without any harm to the blade itself.

The scientists were even able to determine the exact meteorite from which the dagger was forged nearly 700 years ago.

Science is stunning.

Rare glass penny from World War II sells for $70K

Who knew?

I'd heard of the steel pennies from 1943. Heck I've had one somewhere along the way (though I've no idea where it is right now.)

But a glass penny, experimental or otherwise?

That's really cool.

During the war, copper was needed for ammunition. The U.S. Mint authorized tests that included making uncirculated pennies from other metals, plastic and rubber. The Blue Ridge Glass Co. in Tennessee made experimental pennies using tempered glass. (source)

Wooden Laboratory - Periodic Table of Videos

Just about every single thing that we do damages the environment.

At the very least - even if we go as neutral and non-pejorative with that idea as we can - everything that we do changes the environment.

Bit by bit we're figuring out that we can't keep doing that with every building that we erect.

Here's a great video of how the University of Nottingham planned out their most environmentally-friendly laboratory building yet.

They used as little steel and cement as they could, made sure their systems were efficient, brought in natural light wherever they could, included photovoltaics with the windows, and tried to find a way to 'do science in a fundamentally different way.'

Separately, I recommend checking out the entire YouTube channel of Periodic Videos from the University of Nottingham. It's more chemistry than it is material science, but it's fun stuff.

HYPNOTIC Video Inside Extreme Forging Factory: Kihlbergs Stal AB Hammer Forging

I don't know that the video is hypnotic. That's overselling things.

It is, however, impressive to watch the forging that's being done here. I'm especially impressed with how much of the forging is done by hand, the pieces moved, rotated, shifted, pierced - all by hand.

Does anybody know the name of the tool used for the notching done at 2:55? Is it a notcher? A notching tool? A notch? A wedge? A notch wedge? Wedge notch? Triangular wedge notching tool? Notch wedge triangular prism with metal handle?