Metal in Movies is WRONG

I know that you'll be shocked to hear this, but sometimes things in movies aren't real.

Go ahead, take a moment to let that sink in, to let the shock wear off.

In today's video Nate From the Internet addresses times when metals aren't dealt with appropriately in movies - primarily because of the density of heavy metals like gold and because of the black body radiation that should be given off when metals are hot.

I had noticed a couple of these myself - the 'molten' gold in The Hobbit and the weight of gold in The Italian Job 'remake' - but neither took me took much out of the movie. In the case of The Hobbit, it's because I wasn't enjoying the movie anyway. In the case of The Italian Job, it's because the cast is just so darn charismatic that I enjoyed the movie anyway.

Gold karats, percent purity, and uses

 

Nice little reference chart...

Making an atomic trampoline

I've said it before, but an atomic trampoline demonstration set-up would make for a spectacular gift for your favorite neighborhood blogger.

NileRed took a different route than I've taken - which is mostly just wishing that I would stumble across an atomic trampoline and not really doing anything at all to make that happen - and decided to make a disk of amorphous metal on his own.

Admittedly, one of our ASM Master Teachers has a lead on getting sets of amorphous metal disks for us to have in our classrooms. It involves the material scientists at Apple's headquarters in California and turned out to be much more complicated than expected because - as NileRed finds out - the adhesive used to affix the amorphous metal to the steel base is highly relevant in maintaining the ridiculously bouncy nature of amorphous metals in this application.

Here's to hoping that my strategy of doing nothing and just hoping things will work out will...um...work out.

I'll include the Grand Illusions videos that inspired Steve Mould's video that in turn inspired NileRed's above video...

Glittering 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.

Why Don’t Railroads Need Expansion Joints?

The title of this video - which might change since I'm writing this up just a day after it was posted to YouTube - is a bit misleading. The actual question in the title - why don't railroads need expansion joints - is only answered in the last half minute or so of the video and is answered more thoroughly in a Practical Engineering video that I'll post after a jump.

The bulk of the video is spent explaining how railroad welds using thermite work. The video explains the nuances far better than other thermite videos I've posted before, explaining why the rails must be aligned and peaked, why the rails must be preheated (including a nice demonstration of heat treating), how the crystal structure changes as a result of the weld, and eventually why the rails don't need expansion joints.

This is the second of at least three thermite videos from Dr Derek. I thought I'd posted the first video to both blogs, but I can't seem to find it, so it'll likely show up next week.

Aluminum and mercury

I'm thinking that the dangers of mercury thermometers on aluminum-skinned airplanes has mostly passed us by - both because home mercury thermometers are all but outlawed and have been replaced by digital thermometers and because so little of a commercial airplane is being made out of aluminum at this point.

But the demonstration of the formation of mercury-aluminum amalgam is still really cool to watch.

Australia

 

See, it's funny because Au is the symbol for the element gold, so Au-stralia would be a stralia made of (or maybe colored) gold.

Ag-stralia would be a stralia made of silver because Ag is the symbol for silver.

Cu-stralia then would be a copper stralia because Cu is the symbol for copper.

You can read more about these element's - and eight more elements - symbol origins in this infographic from Compound Interest.

Why on Earth is Depleted Uranium Used for Military Ammunition?

Depleted uranium just sounds terrifying. Sure, you can pick up some uranium ore and yellowcake from United Nuclear, but trying to buy depleted uranium is going to likely be a little dodgier.

With that being said, the US military has used depleted uranium (DU) as a source of armor penetrating ammunition over the years. I thought - wrongly from the video above - that the DU was simply used because of its high density and nature otherwise as nuclear waste. Today's video posits that there are quite a few other advantages of DU in high-caliber munitions applications.

There are also some seemingly obvious health risks involved in living in an area where spent DU shells are peppering the ground or having been in a tank where DU rounds entered and as least slightly vaporized. The video also goes through those health risks and says that they have largely been disproven, though I would be skeptical and appreciate that many military branches are "not considering depleted uranium anymore because of the environmental problems associated with it, be [they] real or perceived."

I think I'll stick to good ol' tungsten for my armor piercing needs.

Green hands and green horns

A couple of years back, one of my AP chemistry students asked me if I knew why her hand turned green when she played the French horn.

It wasn't something I was familiar with, but I had a decent guess that green on the hand was a reaction with something copper-based...and brass is certainly copper based.

With a little looking up and finding the various brass compositions used in brass instrumentation - 67-89% copper in the brass used, I feel pretty certain that it's the copper corroding and creating that green residue - on the instrument and on the hand.

My student - MK of the Eastman School nowadays - said that she tried one of the suggested solutions -  lacquer on the horn - and didn't care for how it changed the tone of the instrument. If anybody has a better suggestion, I'll pass it along to MK.

Why copper pans are great (and sometimes poisonous)

I can vouch for that Harold McGee book referenced toward the beginning. I have it on the shelf in my living room - though I'll admit that I've barely read more than a third of it. There's a LOT of science happening in there, and it's a dense read.

Adam explains the basics of heat conductivity, reactivity (leaching ions to make whipping egg whites easier), reactivity again (to pull sulfur out of the vapor distillate in alcohol distillation), malleability (peening the copper bowl), ductility (making copper whisks), reactivity another time (such as the health hazards of drinking acidic cocktails like mules from copper cups), and conductivity again (useful for making jams and candy).

And then he throws down the possibility of testing a pure silver pan...I want him to buy one, but I'm not going to support him to make that easier for him to do.

Can You Burn Metal?

TL;DR - sort of

Burning means to oxidize, which kind of means to combine with oxygen (and also kind of means to lose electrons), and metals can oxidize - we just normally call it rusting or corroding.

So, yes, metals can sort of burn but mostly it happens too slowly for us to notice it happening whereas burning happens way faster. To get that to happen, you'll need to get more metal exposed to more oxygen all at once - like by burning steel wool.

It's not pyrophoric or anything, but it's kind of neat.

Weird metal that's also a glass is insanely bouncy

I've been looking for an amorphous metal demonstrator off and on for a few years but with no success.

There are some samples of amorphous metals available on ebay, but I really don't have any idea of what those metals actually are, whether they're really the zirconium-beryllium-titanium-copper-nickel alloy that Steve describes at 7:10 in this above video.

This video sees Steve explore how to optimize the bounces - which material should the ball bearing be made from, how big should the ball bearing be, how can you measure the number of bounces most easily - which is cute, but the big payoff in the video comes after around 10:00 when Steve explains how materials plastically deform and why amorphous metals don't easily deform plastically.

That's absolutely fascinating, and I even more desperately want one of these atomic trampoline demonstrators.

Feel free to hunt one down and buy me one for Christmas. I'll happily give you my address if you do get ahold of one.

Now I'm curious how an amorphous metal would respond to a hardness test. Would it be much tougher to create a traditional 'dent' from a hardness tester?

(In hunting down more info on amorphous metals, I might've found a preliminary answer to that one on the LiquidMetal website, scroll down partway to find hardness data.)

Here's more info about amorphous metals and a video from Grand Illusions, from whom Steve borrowed his atomic trampoline demonstrator.

• MRSEC at UWisconsin - amorphous metal page
• LiquidMetal - the trade name under which the amorphous metal is available
• A white paper about the Atomic Trampoline from UWisconsin & Arthur Ellis
• LiquidMetal's wikipedia article
• "The Case for Bulk Metallic Glass" paper from Science Direct
• A white paper from Taylor Edge electronics about metallic glasses and the atomic trampoline demonstrator
• Information about vitreloy, a different commercial name under which metallic glass has been available

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.

Exploding Wires & Amazing Molybdenum

I appreciate the playfulness of the Manchester chemists playing around in their videos. They show great curiosity and seem honestly fascinating by the results. The above video shows them running electricity through wires of various metals - copper, aluminum, magnesium, brass, tungsten, gold, molybdenum - in open atmosphere.

Even more impressive to me is their tenacity in trying to explain something once they get unexpected or at least curious results. In the video below, they explore the phenomenon of molybdenum wires producing what they refer to as unduloids - regularly spaced molybdenum blobs - on the surface of the heated wire. 

The Bizarre Market for Old Battleship Steel

Oddly, I had heard that old battleship steel - from before the development of atomic/nuclear weapons - was highly valuable for non-radioactive shielding material.

This video does a great job explaining how the Trinity explosion - and subsequent open-air, atmospheric testing of nuclear weapons - polluted any steel made after those tests via the Bessemer process for producing steel from pig iron and using atmospheric air.

I did not know, however, that the battleships scuttled at Scapa Flow had subsequently been salvaged and some of the steel used in this way. (As an aside, your friendly, neighborhood blogger has visited Scapa Flow. It's gorgeous.)

And I also didn't know that the demand for this low-background steel has mostly been superseded because of the switch from Bessemer to basic oxygen steel production.

Super Expensive Metals - Periodic Table of Videos

Are they really worried that The Professor is going to rob the place that they had to strip him and even take away his belt?

Rhodium, iridium, palladium, and platinum are impressively un-reactive, noble metals.

In the video today we get to see these catalytically useful metals being processed from sponge (what I would think of as ore).

I love seeing what I think of as a crude process like forging being used to reshape the incredibly expensive ingots.

And I doubt these are the absolutely most expensive metals out there - I'd put the sodium from previous videos up there - but it is a chance to answer a question I get from students from time to time: "what is the most expensive element?"

Crystal Birth

Crystal Birth from Emanuele Fornasier on Vimeo.

That's just pretty...and relaxing to watch.

Here we get a bunch of chemical reactions producing metal atoms from metal ions. Some are single replacement reactions. Some are - I think - electrical reduction (I'm assuming that because there are gas bubbles appearing in some of the reactions).

For the most part, we get very little information as to what reactions are taking place, with the only text in the video saying things like Bi⁺³ --> Bi but not mentioning any anions being involved.

Either way, this is definitely reduction happening as every reaction changes a metallic ion into the metallic atom that then forms the crystal.

Stick around for the lead crystals at the end (from about 2:23 onward). They're gorgeous.

And not lead crystal...lead crystals.

Rare World Metals Mint

Check out Rare World Metals Mint.

They sell - and I know this will shock you - rare metals that have been minted.

Mostly they sell one troy ounce samples of rare metals in high (99%+) purity. They don't do bulk. They don't do raw. They just sell these samples for - as far as I can tell - collectors who want to have rare metal samples.

They do offer some relatively inexpensive offerings.

• a minted AVDP ounce of copper, for example, is going for $1.49 as I type this
• nickel is $3.95 per AVDP ounce
• zinc for $8.95 per troy ounce

but things go up quickly from there...

• rhenium $179 per troy ounce
• iridium $1895 per troy ounce
• palladium $58.95 per gram
• osmium $965 per troy ounce
• rhodium $3500 per troy ounce
• platinum $59.50 per 1/25 of a troy ounce

...because why not splurge if you're going to collect the good stuff?

As they write at the end of their rhodium description, "own what's rare!"

I wonder if they have a wishlist feature so I can make life easy for my loved ones this Christmas...

How Not to Put Out a Metal Fire - with Steve Mould

I remember watching WGN a couple of decades ago about a fire at a metals recycling company in Chicago (maybe this one?) The thing that fascinated me at the time was watching the firefighters spray water on the fire, have it explode, and repeat the process a couple more times. The fire chief at the time - in my deep memory, at least - said something to the effect that they knew the explosion was likely but that they were trying to dump enough water on all at once to cool the fire enough to stop the burn. Not enough water = explosion, though.

In the above video - the Royal Institute - Steve Mould shows why magnesium fires are such a bear to put out. They don't - as the article linked above says - 'produce their own oxygen', but they do tear oxygen off of carbon dioxide and water. Once that happens, then, the fire allows the hydrogen and oxygen (from water - or oxygen and carbon (from carbon dioxide) to react with the magnesium or with each other producing an even hotter flame.

Hmmm...seems magnesium's active or something.

(And I don't think - at 2:55 - you 'can actually see [the beaker filling with carbon dioxide]', Steve. My understanding is that carbon dioxide is invisible. What I think you're seeing is fog, condensing water vapor due to the coldness of the dry ice.)

Making metal crystals from Pepto-Bismol

Admittedly, at first I looked at this video with some excitement, thinking that I might be able to use the procedure to demonstrate reduction of a metal in my material science class - or in chemistry.

But the procedure is insanely problematic and long and scattershot in its success. There's no way that rookie science students could perform this with any level of success.

It is, however, frickin' cool to watch.

Plus the video is insanely high def.