littering war zone halos named for fallen heroes

Stick with me, folks.

I wouldn't normally turn to Fox News for my science reporting, but their story does the best job - of the ones I quickly searched on YouTube - of explaining the Kopp-Etchells effect in which the edges of helicopter rotor blades get abraded via airborn grains of sand, sending showers of pyrophoric tittanium-nickel alloys into the air and making for a lovely light show - that admittedly shortens the lifespan of the blades and advertises the presence of the helicopters at night.

Effectively, it turns the edges of the blades into sparklers.

It makes for some really pretty pictures, though...

Source - reddit

Source - wikipedia

Here's another video with a little more science presented in meme-ified format.

In Space, No One Can Stop You From Welding

Cold welding is frickin' weird.

Richard Feynman wrote (or said in a lecture - I'm not sure which), "when the atoms in contact are all of the same kind, there is no way for the atoms to 'know' that they are in different pieces of copper. When there are other atoms, in the oxides and greases and more complicated thin layers of contaminants in between, the atoms 'know' when they are not on the same part."

But two metallic pieces that don't have those thin layers between them - primarily because they've been in space and rubbing against each other - can spontaneously weld together to become a single piece of metal.

It's possible to get that to happen on Earth, but it's not easy because of all the pesky oxygen we have around us all the time.

Metals are way weirder at the quantum level than we think they are, man.

What is epoxy coated rebar and why is it being banned?

I feel bad for this youtuber having to broadcast to us from some sort of white void with bad lighting or white balance without understanding how low quality his image is compared to the quality of the images that he's sharing 'behind' him. And I don't know why he won't make eye contact with me. He keeps looking at something above and in front of me that I can't see.

Sorry for the snarkiness. 

I've been watching a lot of very professionally made YouTube videos recently, and it's easy to see how much better those look than this more amateurishly produced videos, but I will admit that this guy gives a great explanation of why epoxy coated rebar is used (corrosion prevention), the problems with it (the epoxy rubs off unless the rebar is handled very gently before sealing it in concrete leading to pitting corrosion and debonding), and pros and cons of possible solutions (high costs due to scale production and lack of building code acceptance).

It's easy to think that simple solutions (just paint the rebar) won't lead to secondary problems (the paint rubbing off).

(Oh, and respect to BadLandsKid who had the top comment on this video when I accessed it most recently, "Very galvanizing topic. While it’s not set in stone, it reinforced my views on rebar.")

DoD Corrosion Prevention Podcast

So much needless special effects and multiplication of the speaker. - and motion that does more to distract from that focus us on the message. This video just screams 90's to me even though it was clearly produced in the 2000s.

I had no idea that we had a director of corrosion policy and oversight (corrdefense).

The most useful part of this video might be in the distracting animation of the 12 types of corrosion that rotate at the top of the video.

And I'm not sure I'd call this video a podcast.

The Importance of Corrosion Prevention & Reinforcing Our Nation's Infrasctructure

Not really a surprise that painters want us to know that bridges and infrastructure can corrode. It's like they might have some sort of financial interest.

I don't know that they had to go to the efforts to photoshop out the bridges in the intro, however. That's a little creepy looking.

There's a really nice animation at 1:10 showing the anode and cathodes forming on the same piece of iron, then they mostly go into showing how we can prevent (or at least minimize) corrosion via inspection and maintenance (mostly through painting - I'm sorry - through 'coating appli[cation] by certified coating application specialists on a regular maintenance schedule')

Corrosion in Motion Golden Gate Bridge

Doncha just love student project videos?

At least it looks like these kids might actually have been at the Golden Gate Bridge for some of their filming. And while their special effects aren't exactly on a professional level just yet, they gave the monster attacks, earthquakes, and explosions a good, college (or high school) try.

They do a decent job explaining why the iron oxidizes, including a pretty thorough writing of the chemical reaction of the rusting of iron. They also show a cross-section of what galvanizing layers look like and what reactions work within the galvanizing.

The video does end a bit abruptly, but it's not a bad effort. I'd be impressed if my students produced this video. Maybe this'll be something to work toward for next year.

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.

Kinetics are important

See, it's true because oxidation is just something losing electrons...and burning involves something oxidizing by combining with oxygen.

It's funny, see?

It's also relevant to material science for when we do the iron wire demo and see that oxidation happens more quickly at high temperatures.

Source - XKCD

Color: a spectrum of possibilities for your ring

I desperately want a titanium ring, and I'm really curious to get one that's anodized in some gorgeous color(s).

I just can't figure out which ring I want. There are tons of choices.

The titanium, then, can be oxidized to produce gorgeous colors. The process of creating an oxide coating on a metal via application of electrical current is called anodizing.

One of these years I'll get around to trying to do some anodizing myself, but I'm going to have to get a steady supply of titanium before I can use it as a class lab. Titanium's kinda expensive and really, really hard to cut - something that I need to consider, too.

When I do get around to it, though, I'll check back on these instruction pages.

As a warning, there isn't really any color to the oxide layer. It's caused by light wave interference. Check the science out if you really want to know.

If you were thinking of a gift for your favorite material science blogger, I'll need to measure my ring size first, but this one's the current choice.

Light bulb filament

This video, made to accompany an article on Wired magazine's website, absolutely blows me away. First off, the ease with which The Engineer Guy takes off the glass envelope of the light bulb at 0:45 is stunning. Can anybody recreate that with a pipe cutter? I've been trying for a couple of weeks with absolutely no luck.

At 0:58 then, the video does a great zoom in on the supercoiled tungsten filament and shows the original 20-inch filament coiled then coiled again.

The next part of the video - from 1:30 through 2:30 - explores the ductility of tungsten and the processes necessary to make it ductile. The six steps - at 2:00 - absolutely blow my mind. That anybody could ever figure those steps out is amazing.

And the video closes with explaining the need for the glass envelope and the gas within.

Great, great video!