See, it's funny because it isn't remotely helpful in memorizing the elements on the periodic table.
This is from a 2010s animated comedy series simply called Mad and modeled after the comedy magazine of the same title.
See, it's funny because it isn't remotely helpful in memorizing the elements on the periodic table.
This is from a 2010s animated comedy series simply called Mad and modeled after the comedy magazine of the same title.
In case you wanted to learn a little more about triboluminescence, the subject of last week's post...
Though after watching this video I'm confused as to how this is different from piezoelectricity - my understanding of which seems to match the explanation given here of the asymmetrical crystals becoming differentially charged as the crystal is disturbed or broken.
Most of this video - as is typical of videos from these ridiculous Aussies - can be skipped. It's primarily just repeated, slow motion footage of two giant air cannons firing random things (plastic dinosaurs, basketballs, cola cans, pumpkins, rubber band balls, spray paint cans, and such) at each other and ridiculous mugging for the camera.
But then - at 16:30 - they fire two glass balls at each other and something really interesting happens.
Well, at 16:30 they load the two glass balls and mug around for two and a half minutes before showing us the scientifically interesting slow motion video. Go ahead and skip to 19:00 to see the science.
I'll wait for you...
At 19:24 we get a flash of light when the two highly accelerated glass balls hit each other.
The flash of light certainly wasn't something that I expected to see and seems to be an example of triboluminescence (light produced from force or movement).
The initial science explanation (at 20:00 about IMFs being broken) seems a bit dodgy, and I'm really happy that they come back around 21:00 with something that sounds more correct to me.
I've never heard of glass causing triboluminescence (nor fractoluminescence which is a subset of triboluminescence, I guess), but I'd like to see somebody with way more science knowledge than I have explain what's happening here.
Thanks, by the way, to reddit for the gif.
A few years back - when we were still in the previous iteration of Princeton High School - I had my AP chemistry students make cupcakes with three separate leavening methods: baking soda, baking powder & soda, and mechanical leavening (whipping egg whites). The three methods are fascinatingly different and produce very different results.
In this video Adam and his baker friend look at the differences between box cake mix and from-scratch cakes. They're not quite looking at just the leavenings, but the science behind the differences are fascinating.
I'm sometimes sad that we went with material science rather than food science as one of our science electives at Princeton. I wish I had a good curriculum for high school students to explore food science, but that would also require a cooking classroom - something that our principal at the time of the building of new Princeton High School wasn't interested in building anything that practical.
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.
The source of this image is a reddit post which included only the following explanation, "The bathroom in our science building has the periodic table in tiles".
I need more info.
Where's the building? I assume it's a university science building, but there's no info provided.
Why do the metalloids seem to continue diagonally down from the table itself?
How old is the bathroom design? Nihonium (element 113) is the last element shown, and that was created in 2003 or 2004 with the discovery not adjudicated until 2015.
Why do the metalloids, halogens, and noble gases get to continue upward into the border design?
(Oh, and I can't take credit for the title joke. That came from the first comment on the reddit post.)
I know, long-time blog followers have seen the floating stick man phenomenon before.
...but they haven't had Steve Mould explain why it works before, nor have they seen it used to animate an alien abduction.
tl;dr - They use solvents with weaker IMFs that water - some of which are nonpolar.
It's been a big improvement over the ancient Roman 'dry scouring' which was based on fuller's earth, lye, and urine-sourced ammonia.
The solvents used have varied over time from turpentine, gasoline, benzene, and kerosene (all highly flammable, carcinogenic, and stinky leading most dry cleaning facilities to be located outside of densely populated cities) to tetrachlorethylene (which is less flammable but toxic to plants and animals and can lead to neurological issues like Parkinson's disease).
So, dry cleaning isn't remotely 'dry.' It's just cleaning with gentler machines using solvents that evaporate more quickly and readily than does water.
Liars...
That ad is so 90s that it should've been parodied on the Bill Nye show.
Hypercolor - a brand of thermochromic clothing that changed color when it warmed up - was a very narrow slice of popular culture, lasting only about a year in the popular culture of the time.
The science behind the thermochromic dye was pretty cool, similar to that used in touch-sensitive thermometers, but the fabric and its dye wasn't built for long-term wear.
Sadly, though, after a handful of washes, or one laundering misstep in too-hot water, the magic powers faded and the shirt froze permanently into a purple-brown mushy color. (source)
If you want a hypercolor shirt, the easiest way is probably to make one of your own.
Sadly the picture isn't quite right in that the second row would need to be eight seats wide compared to only two seats for the first row. Or maybe four seats compared to one with people sitting on each other's laps to represent the Pauli Exclusion Principle.
All that would need the shadow line to be shallower, more of a 15 or 20 degree angle rather than the 45 that's in this picture.
But then the sun wouldn't be as bright and harsh when it was that low in the sky meaning that the people likely wouldn't be seeking out the sun as overtly and urgently.
So maybe it's best not to question this but rather to chuckle at it and move on.
And definitely don't go listening to the "Electron Configuration Polka" by Michael Offutt.
Take what this YouTuber has to say with a grain of salt. I will admit that I haven't researched and confirmed his claims, though I have watched all of the videos I'm posting today. I can say that they confirm something I've long been skeptical of: it seems unlikely that glorified sunglasses could produce colors in the eyes/brains of people who genetically can't see (or maybe can't differentiate) colors.
The enchroma glasses (and other, similar brands) seem to block a narrow band of colors leading to a greater differentiation between green and red meaning 'color blind' people can distinguish those colors more easily and can pass various 'color blind' tests like the classic numbers inside a circle. What the glasses seem incapable of, however, is actually letting those people see different colors that they inherently cannot see.
The science behind 'color blindness' is well explained here as is the science of what the glasses actually can do. The videos also explore common issues with scientific research - both conflicts of interest and confirmation biases as well as social pressure leading people to report results that may or may not actually be there.
So, I'm going to fail that captcha.
I've posted about this black fire on the blog before.
This one - from Steve Mould - doesn't add a whole lot new to the basic technique of shining a sodium vapor light on a methanol (stay safe out there, folks) flame that has been doped with sodium chloride. It does add in some more information on how the spectra are created and some info about enchroma glasses (more on them next week).
Can I lick it?
Carl Wilhelm Scheele was likely the first person to isolate and prepare pure oxygen gas - though sadly for his historical reputation, not the first to publish his results.
Scheele also has gone down in history as a chemist known for tasting many of the chemicals that he experimented with in his laboratory.
So, can - or should - you lick the various elements?
Some -the green ones - would probably be okay. Go ahead, for example, and lick a penny. It might be germy, but the metal itself isn't going to be a problem.
Other - the yellow ones - wouldn't be great, though they're not going to immediately kill you.
The red ones will likely immediately kill you or seriously harm you without much of a doubt.
The purple ones are radioactive and will kill you quickly.
So, can you lick it?
Maybe you can.
I promise these will be the last few joke posts for a while. I'll go back to more informative content next week.
See, it's funny because this is the easiest joke for any chemistry teacher or student to make. We build plastic water molecules for lots of purposes. The ones I use in class are magnetic to show the IMFs appropriately.Fluorine would be Henry J. Waternoose III trying to take Boo from Sully in Monsters Inc except that Sully eventually is able to get Boo back.
No element would get its electron back from Fluorine.
Then I read it a little more closely and saw that it's claiming there are more hydrogens in a molecule or water than there are stars in the entire Solar System which is flatly true since there's only one star (the sun) at the center of our solar system.
It's misleading because "more _______ than there are stars in the galaxy" is a common phrase, and "more ______ than there are stars in the Solar System" is not a common phrase because it's dumb. It's just saying there's more than one of something.
Source - xkcd |
Here Randall Munroe has classified the modern elements on the periodic table into airs (elements that are gaseous at room temperature), waters (elements that are liquid at room temperature - Br and Hg), earth (solids at room temperature), and fire (the radioactive elements).
Not a lot to figure out there, though there is still an explainxkcd article on it.
Oh, and congratulations if you figured out why I posted this today.
Hydrogen bonds are usually considered to be intermolecular forces attracting separate molecules to each other (or parts of one molecule to different parts of the same molecule as in DNA and proteins' tertiary structures).
Covalent bonds, on the other hand, are intramolecular forces holding atoms together within molecules. They aren't usually considered IMFs unless we get into the grey area of covalent network solids.
Source - macosicons.com/#/u/antonin1802 |
Amongst the many issues...
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.
As I mentioned last week, I toured the Indianapolis Art Museum's conservation lab as part of our summer ASM materials camp a decade or so ago. It was a great tour given by Dr Gregory Smith, star of this series of videos through which he explains the process of verifying the age and pedigree of an Uzbek Coat of Many Colors.
The rest of the four-part series is after the jump.
Give 'em a break, alright?
It was the pandemic. People were trapped in their houses. They were doing their best to create content that was interesting and that could be enjoyed remotely.
No, a video of two people talking remotely to each other while narrating a slide show isn't necessarily the most exciting of presentations, but I can vouch for Dr Smith being an entertaining guy. He gave me and our summer ASM campers a tour of the Indianapolis Museum of Art's conservation lab about ten years ago, and it is one of the more unexpectedly great tours that I've been on through those summer workshops.
Take some time and see what Dr Smith has to teach us about art conservation and forgery detection today.
Source - link |
I usually add the fact that most of those videos, however, are now a decade old, and I haven't seen the product being used. Thankfully one of my campers last summer took that as a challenge and went hunting for an update.
Here's what he and I have been able to find...
I remember having flash cubes in cameras when I was growing up, but I had no idea how literally explosive they really were.
There's a lot of build up and explanation, but the money shot really shows up around 20:30 and onward. It's then that they get the right resolution and exposure time to see what's really happening within the flash bulbs when they ignite.
Our phones are miraculous, but their flash isn't nearly as cool as a flash bulb ever was - much less the original limelight.
Source - Reddit |
Though the table needs to be updated with the newest elements and the names for elements 110 and 111.
See, it's funny, though, because many - but not all - of the inner transition metals are radioactive meaning that their nuclei are unstable and will decay into more stable nuclei.
It's a joke that requires a little chemical knowledge but that falls apart if you have a lot of chemical knowledge.
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.
I'll admit that I knew most of the name origins of the elements in this video.
There were a couple of that I'd either forgotten or hadn't known. Tellurium, antimony, argon, and a few others on the list at 13:25 surprised me.
In the end, I don't know that's it's the most helpful thing to know the origin of an element's name. It's historically interesting and might tell you something about the element, but it's also possibly a misnomer, oxygen, for example doesn't necessarily for acids, but its name suggests that it does.
Mark Miodownik is the author of one of the better materials science books written for a popular audience, Stuff Matters.
In that book he takes a chapter to explore each of the various material categories and some of that category's most common exemplars.
Here, however, Miodownik looks at glass to see why light can pass through it. Turns out it's all about electron transitions.
Stephanie Kwolek absolutely belongs in the inventors hall of fame, in the women's hall of fame, on the American Chemical Society's website, and on lots of other lists of honorees.
Stephanie Kwolek, you see, invented Kevlar at DuPont in 1965.
I've posted a couple of videos of this demonstration before, but this one does a better job explaining how to do the demo than those others did.
As always, let's be careful out there, folks.
I've posted before about the importance of pH on food preparation, but the increase in browning is one of the easiest ones for home cooks to exploit.
Want something to brown better without having to increase the heat? Increase its pH.
With that being said, I personally can't stand big, fluffy pancakes. Give me thin pancakes any day of the week.
If you're interested in food chemistry, check out On Food and Cooking by Harold McGee, How to Read a French Fry by Russ Parsons, or The Food Lab by J Kenji Lopez-Alt. I own them all and have read through and cooked out of some of each of them.
This Monday's post was a little light on the science, so I thought I'd add in a heavily-sciencey video to make up for it.
The concept of entropy is a big, dang deal, but it's often reduced - at a high school level, at least - to being defined as 'disorder' or 'randomness'. I try to explain to my students a slight bit of the subtlety, but I'm not entirely sure how much sinks in for them.
Thankfully, AlphaPohenix has a video explaining entropy really well.
My son texted me a bit upset this morning because he broke a beaker in his high school chemistry lab and brother can all we chemists tell him some stories
— Keith Hornberger (@KRHornberger) March 6, 2024
What’s the biggest / most expensive piece of glassware you’ve ever broken? pic.twitter.com/tIujO4qGCm
Source - Buchi |
That is amazing...and gross...and sad...and a marvelous encapsulation of our world.
I had no idea that the stuff grandpa used to put on some of his wordworks - or at least the etymological origin of what he called what was probably varnish or polyurethane by then - had its origins in bug secretions meant to protect them while they nibbled on trees.
There's so much to say about the dyes that are used in our food from whether artificial or natural dyes are better, why certain red dyes aren't vegan friendly, whether some dyes can cause or affect ADHD, why we need to dye our food at all, why Aldi isn't using artificial dyes in any of their products, and much more.
This video is a bit long at twenty minutes, but it covers a whole lot of ground.
Source - xkcd |
There's a whole lot of jokes there - my favorite of which is the "You Are Here" triangle.
Enough jokes, in fact, that I'm going to let explainxkcd explain why it's funny.
This video is, admittedly, from 2011, so the "just published" article (read it for free here or here or a summary here) that's mentioned in the beginning is well past its newness by now.
At some point the periodic law isn't nearly as neat and clean as I teach my students, and I kind of love that fact. The fact that the edge cases of superheavy elements start to stress our understanding of the quantum mechanical model is fascinating and to me shows that there are more things in Heaven and Earth...
Source - wikipedia |
That just doesn't seem right.
I get that esters like methyl anthranilate are pretty typical in the artificial flavor and smell world. In fact, when I was a high school student, we made a banana ester (isoamyl acetate - hmm, I wonder if I could bring that back for my chemistry classes next year.)
But the soaking of an apple in something that's used as a bird repellant to make a grape-flavored apple (check the Grāpple website via the internet archive) seems...problematic.
I was cleaning up my bookmarks this summer and found that I have a whole bunch of backed up videos and articles for my two blogs.
My first step was to post ahead one video or article per week until the end of the calendar year 2024. Now that I've gone ahead and done that and still have a ridiculous number of saved bookmarks.
The next step was to ready a second post per week (Fridays this time to balance the already-ready Mondays), and this is the first of those Friday posts.
There won't be any particularly difference focus of the Friday posts, but you'll just get twice the content from me.
This video explores why most people think that radioactive materials give off a green glow (they don't) through the history of radioactivity's discovery including the radium girls' sad story.
Thankfully the video closes by pointing out that there is actual Cherenkov radiation that causes a light blue glow from radioactive materials in water.
American cheese is sort of cheese.
Well, it's cheese with some sodium citrate added to it, anyway, stabilizing the emulsion of fat and water that normally breaks when any aged cheese is heated and melted.
And it's tasty and heck, so shut up.
(I'm tempted to buy that sweatshirt that Dan's wearing - but more likely in maroon than in yellow.)
Ah, NileRed eating and 'cooking' in lab again...
American cheese cannot legally be called cheese. Cheese is legally defined as...
The fresh or matured product obtained by draining after coagulation of milk, cream, skimmed, or partly skimmed milk or a combination of some or all of these products and including any cheese that conforms to the requirements of the Food and Drug Administration for cheeses and related cheese products
...and American cheese contains ingredients added to that to encourage emulsification of the fat and water so that the cheese won't break when it melts, meaning the fat and the water won't separate and create the oily puddles that you get from melting cheese.
So American cheese is technically a processed cheese product.
...which NileRed explains and demonstrates in today's video.
Maybe maybe maybe
byu/Make-this-popular inmaybemaybemaybe
Yes, like iron.
I'm reminded of a question that one of my former students asked me quite a few years ago. We were two thirds of the way through the year of honors chemistry, and she said that she had been reading the ingredients on her toothpaste the day before and found sodium fluoride. She asked if that was the same sodium and the same fluorine that we'd been talking about all year.
"Yes," I said, "it's the same elements."
She followed up, "so, are there other things in my house that are made of elements?"
"Yeah," I answered, "everything in your house - and the house itself - is made of elements."
"Like, the same elements on the periodic table?"
Clearly, Sarah (or maybe it was Sara - it's been a while since this conversation) was one of the lucky ten thousand that day.
I've done the iron demonstration below in class before - though I used a blender to get even more iron particles out of the cereal by chopping it finer.
The video at the top, of course, also shows one of the lucky ten thousand today.
Source - Cyanide & Happiness |
Then again, the circles of hell as described by Dante Alighieri in his Inferno suggest that the lower levels are for the greater sinners where greater punishment is meted out, and that image seems to have permeated the popular consciousness, so Joe's thinking seems to be reasonable.
Maybe this is another example of two people both being correct but simply not communicating with each other.
Just talk it out, Devil and Joe.
Then again, if we assume that hell is somewhere underground - maybe under Turkmenistan, maybe somewhere else - then the geothermal gradient should likely be considered.
Source - Reddit |
I would 100% study in that building.
It took me a while, but I was able to find that it's at UNAM (Universidad Nacional Autónoma de México) in Mexico City. Here's a Google Map link.
And I appreciate that it's up to date.
No idea what they'll do when the eighth period has to be populated, though.
Source - XKCD |
That would be so much easier to memorize.
As you can see if you look at the timeline of the Big Bang, that's about right that half an hour after the big bang, the only elements would have been hydrogen (75% of the universe's mass), helium (25%), lithium (trace amounts), and radioactive beryllium.
Of course, I'm not sure what this periodic table could've been printed on - or by whom, but that's not the point.
The rollover joke - Researchers claim to have synthesized six additional elements in the second row, temporarily named 'pentium' through 'unnilium'. - is also outstanding.
I've done that.
Quite a few years ago, in class, I had some liquid nitrogen thanks to the parent of one of my students, and I was able - with the help of a vacuum pump - to repeat this demonstration in class.
I'm not sure my students were nearly as amazed as I was, but it's a singular occurrence for me.
Very cool...(pun intended)...
As they say, "Diamonds are forever."
That's what they say, anyway, but chemically it's not remotely true.
Diamonds are just a covalent network of carbon atoms and occasional impurities. Those covalent bonds are fairly easily broken in a combustion reaction at a high enough temperature.
That's why I tried to convince my wife that cubic zirconia was the fare more durable, stable, long-lasting choice to show the permanence of our love.
She wanted a diamond, though.
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.
Simple enough, eh?
I remember my dad saying that he used to play around with toy carbide cannons when he was growing up. By the time I was a kid, however, carbide cannons as children's toys had gone well by the wayside because of the danger involved.
The Rose Hulman Fighting Engineers (seriously), however, still fired one off in their quonset hut of a gym (since replaced) back when I was a student at Wabash College and occasionally travelling to watch the basketball team. I can't remember exactly why they were firing off the cannon. Maybe it was for their football team and I'm misremembering things. I can't find proof on the internet either way.
Check out some more carbide toys after the jump - including a far safer way to demonstrate this reaction thanks to Steve Spangler and Bob Becker.
Yes...sort of...
The video above explains that aerated water in sewage treatment plants - the ones with warning signs saying 'non-buoyant water' - might not be as deadly and non-buoyant as advertised.
From a 1985 study in Indiana, a Mythbusters episode (see below), and a Facebook/LinkedIn post, it looks like aerated water isn't quite as deadly as the signs say.
People do drown in aeration tanks from time to time, and I'm sure it's a very unpleasant way to die, but it appears that the drop in buoyancy - while very real - is apparently counteracted by the upward flow of the bubbles in those tanks. There is also a current caused by the upwelling that can create a circulation pushing any object toward the pool's walls and then downward (sort of like the bubbles in a pint of Guinness).
So, should you ignore the non-buoyant water signs? Not at all.
But is the risk not quite as risky as it's been made out to be? Probably.
In our material science class at Princeton - and in most of the matsci classes that originated from the ASM summer camps, I would imagine - we grow copper (II) sulfate crystals from solution.
It's a fairly easy lab to do, and the students have a high success rate.
For most students, that crystal growing experience is an end, but for others it's just a beginning, a taste of a much richer world of crystal growth.
For those students, crystalverse would be a great resource as it provides instructions for the diy crystal farmer whether they want to grow crystals of copper acetate, monoammonium phosphate, sucrose, alum, sodium chloride, potassium ferrioxalate, or even pyramidal crystals of sodium chloride.
In every case, the procedure is largely the same - make a solution, let the solution cool and evaporate to form seed crystals, continue to let the solution evaporate to grow the seed crystals larger. The great things about the crystalverse website is that it has loads of tips and faqs to help you troubleshoot your growing.
Today you get a whole bunch of videos about making salt.
It seems like such a simple thing - talk salt water from the ocean and boil it down - but there's a lot more to the science of making salt including removing the calcium and magnesium impurities, allowing the crystals to grow to the desired size, and sorting those different crystal sizes.
Who knew that the rate of crystal growth would affect the size of the crystals?
More after the jump...
Heat =/= temperature
Temperature is the average kinetic energy of the particles in a substance.
Heat is energy transferred from one body to another due to a difference in temperature.
Hot things - like boiling water or simmering sauce - conduct energy to cool things - like your finger.
The amount of energy you get from that hot sauce depends on way more than the temperature of the sauce. More mass of sauce that you get on your finger means more molecules with that same average kinetic energy, so more total energy, so more pain.
In this video Adam switches mass out for time in contact with the sauce, but in this case that seems a fair swap.
Don't dunk your finger in hot fryer oil or hot sugar syrup. According to Adam, go ahead and dunk (or flick) your finger in hot, water- or oil-based sauces.
As always, vinegar leg on the right.
I've posted about Phoenician Purple before - the dye mentioned in this video as coming from snail shells. That's an amazing story, too.
The early part of this video defines pigments versus dyes. I'll admit that I didn't have any idea there was an actual distinction between those two. I am curious, though, as to whether the insoluble and soluble designation depends on the nature of the solvent. Like are some chemicals pigments in oil but dyes in water-based solutions?
Maybe I'll hunt down that in a different video.
"It's Dutching time!"
Thanks, Adam.
Turns out there's some serious chemistry happening in the kitchen when you're making - and especially when you're dutching - some chocolate from scratch.
Arrggghhh, Action Lab again.
I want to hunt down some of those dialectric mirrors. Their non-isotropic reflective materials sound pretty cool.
I am amazed that there is no metal in the material. It's just made of transparent polymer layers in alternating materials with different indices of refraction.
One of my coworkers recommended this video to me, and I respect the video host's adherence to the scientific method. He tests metal from the same source, prepared in the same way, and has multiple test samples for each coating.
I'm not so sure, however, what these rust convertors actually do. I found this in the wikipedia article on rust converters...
Commercial rust converters are water-based and contain two primary active ingredients: tannic acid and an organic polymer. Tannic acid chemically converts the reddish iron oxides into bluish-black ferric tannate, a more stable material. The second active ingredient is an organic solvent such as 2-butoxyethanol (ethylene glycol monobutyl ether, trade name butyl cellosolve) that acts as a wetting agent and provides a protective primer layer in conjunction with an organic polymer emulsion.
Some rust converters may contain additional acids to speed up the chemical reaction by lowering the pH of the solution. A common example is phosphoric acid, which additionally converts some iron oxide into an inert layer of ferric phosphate. Most of the rust converters contain special additives. They support the rust transformation and improve the wetting of the surface.
The title of this video is wrong.
There is no freezing happening. There is recrystallization happening from sodium acetate dissolved in solution.
That's not freezing - a pure liquid turning into a solid like ice turning into water. The host seems to understand that distinction, but he's sloppy on using the term freezing and freezing point somewhat misleadingly. He also is sloppy on liquid versus solution and melted versus dissolved.
Most of this video is an explanation and comparison of the two types of hand warmers - the reusable sodium acetate solution and the single-use iron rusting type. The video host explains the science behind what's happening and judges the single-use to be the better choice - something that I'll leave up to you.
I use both in class for different purposes and different chapters.
Source - xkcd Rollover text - Unlike an Iron Age collapse, a Bronze Age collapse releases energy, since copper and tin are past the iron peak on the curve of binding energy. |