I love arrowheads, especially obsidian ones...in 7th grade we went to a Native American historical preservation, there was an older man sitting at a table making an arrowhead out of obsidian with a couple pieces of leather and antler. Me and a bunch of kids started watching him, and they all eventually went to look at other things, but I stood there and watched him the entire time...I dont remember either of us saying a word to each other other than hello. He was finishing it as our field trip was ending, he glanced around, wrapped it in a piece of paper and handed it to me and just said 'shhh'. I gently stuffed it in my pocket and proceeded to hold the biggest secret of my life the entire bus ride back to school, the last hour of school, and the bus ride home before I could have a little freak out about him giving it to me. I pulled it out of my pocket, unwrapped it and marveled at it, it was huge, and sharp, and you could see right through it, totally blew my mind. That was nearly 30 years ago, I still have it, wrapped up safely in a box that I open occasionally when nostalgia gets the better of me. ...now if you'll excuse me, theres a box I need to look at...
unless its highly concentrated and a medium to high amount of acid, nothing much happens except for mostly a slight rise in temperature. try that with a lot of oleum and its a different story...
Every good chemist knows it only applies for few acids like concentrated sulfuric, perchloric, oleum. It's perfectly useless rule for other acids. Nothing will happen if you pour water into concentrated nitric or acids made from hydrohalogenides.
We used to use HF to dissolve quartz that held lode gold nuggets to improve the specimens. Scary stuff even for a Geochemist. We didn't dilute ours though so it worked faster and we could direct it where we wanted rather than just dunking the whole chunk. In regard to your results, you need to remember that while Chert and Agate are primarily composed of quartz (a silicate mineral), Obsidian is simply rapidly cooled lava which contains many minerals other than silicates and those would resist the acid.
I did in my scientific career, boy did I take precautions. I also played with a solution that had the warning not to breath any vapor in or spill whatever, it would rupture my red blood cells immediately and I would suffocate. Joy :)
Next time: Can you swim in mercury? "Of course, the greatest problem is the density of mercury makes it incredibly difficult to immerse yourself. This is why I'm going to be wearing these uranium waders..."
Today we're looking at sarin and ricin, and their etching effects on different containers. ... Shows ingredients ... That fan you hear is taking care of any potential fumes, and we are downwind from any major metropolitan area, so we we're safe.
@@GaiusCaligula234 OK. Instead we're going to use some liquid nitrogen to condense both of them to liquid form, and then mix together within a pressurized vessel? Our goal today is to find a just-the-right mixture, that allows us to induce a slush-like substance that you can use tp disinfect your chicken coop.
I have a feeling we are watching the training videos of a super villain. Step 1: extract all the precious metals Step 2: disolve the 'hero' in acid Step 3: escape to Mars and live peacefully
Nah Cody is one of the good guy chemnist. There are others way more scary (though also good guys... hopefully... *looks at NileRed and Explosions&Fire)
I love seeing videos like this from you Cody. I can feel your genuine curiosity about this experiment and it feels like you did this work to figure something out for yourself as opposed to for your audience. If you ever find yourself thinking "im the only one that would ever watch this", when conceptualizing a video, please dont shelve it. Thats exactly ankles the kind of stuff we love from codyslab. Thank you for being you.
The balls on this guy. Hydrofluoric acid scares my pants off! My chemistry lab TA in college would scold us if we even do much as wrote fluorine ions in our notes. She'd say "You should NEVER be making this ion!" and then told us some horror stories about HF. Then there's the geology grad students. I remember walking past the geology lab once and I saw a grad student in there nonchalantly eating her lunch on a table below a shelf with a bottle labeled "hydrofluoric acid, contact poison" and a skull and crossbones. Only geologists have the balls for such shenanigans. Hey... isn't Cody a geologist? See? I told you. They fear nothing!
Same here! It must be due to the specific way that obsidian forms and its specific composition, where it shears to the monomolecular level and tends to knap in thin sheets, because I expected the thinnest part to dissolve faster than the flat of it, but it didn't!
I was just about to eat lunch, after being sat in front of an instrument at work for 6 hrs straight, looking for something to watch while I eat. Seeing a new Cody's Lab video made me feel a lot better 😊
@@refluxcatalyst7190 What precautions was he missing? Proper "glass"ware, had a nice bed of lime, wore gloves, has a fan? Honestly y'all armchair chemists have probably never even set foot in a real lab lol.
As a flint knapper this is interesting to me. One of the most arduous parts of replicating certain blade types like danish daggers is that they have to be ground to a perfect convexity. Perhaps this could greatly expedite the process!
@@unvergebeneid Who knows how long people having been using acid to shape stone? Maybe this could explain some of the incredible stone work of the ancient egyptians like those hollow vases? Still no good theories on how those were made.
@@frysebox1 Yeah I'm a bit scared of hydroflauric acid ever since watching breaking bad haha. I wonder how effective milder acids would be. Would lye do anything to a rock? It's easy to make with campfire ash. Dannish daggers were ground on a granite slab with water... i wonder if using lye water instead would speed things up at all. Regular water takes like 20-30hrs of grinding.
@@wcomalley HF (with a pKa of +3.2, the less the more acidic) is by no means a very strong acid, it just has the strange characteristic of dissolving silica-based materials like glass. sulfuric (pKa of -2), hydrochloric (pKa of -7), or nitric (pKa of 'i don't remember') are stronger acids than HF, that is because fluorine is so reactive that it bonds hydrogen a little to strongly. Also, HF is very, very toxic, it reacts with calcium ions and causes cardiogenic shock and cardiac arrest if it comes into contact with the skin, It's so bad that pretty much every professional chemist I know avoids as much as humanly possible..
My heart sank a little until you said they wasn’t true Indian arrowheads lol but your friend did a great job making those I found a few real ones here in Indiana close to my house I found one little white one I think it’s a bird point used by Indians for hunting birds very cool I used to love going arrowhead hunting thanks for sharing Cody love watching the videos
The guys over at good and basic have some great content. Primate forging, the spinning wheels and whatnot, too. (The philosophical discussions are interesting as well). Glad to see the interactions between channels like this.
@@Grandwigg wow I never knew one could forge primates! Crazy! (I am just having a little joke) That’s all really cool though sounds like their channel is right up my alley thanks mate
My heart sank even more because being the eurocentric prick that I am, I thought these might be neolithic! I somehow didn't put together that in the US, authentic stone arrow heads must be much more common and only a couple centuries old.
Imagine if they had access to and could have worked with HF acid for sharpening their hunting arrow tips... lol... I found a few when I was a kid visiting my grandfathers farm in Burlington, Ontario... that was neat for a kid to find.
Very cool experiment and demonstration. I think the "snowflakes" in the obsidian may be volcanic ash that fell in the molten obsidian flow. Even though the materials of obsidian, agate, and flint/chert are especially suitable for knapping stone tools because of their characteristic conchoidal fracture, they are formed differently. Many people probably do not know this regarding stone tools, but for a razor sharp cutting blade our ancestors used blades similar to the un-knapped piece that sliced the paper best. Even though knapping could thin and nicely shape arrow heads and other tools, it's more difficult to get a continuous sharp edge that way.
Dang, you should have written the date on that arrowhead… Although it’ll probably be just an arbitrary number when someone discovers it in an asteroid 12 billion years from now, long after the earth has been annihilated
When the video started i immediately thought about the typical "glassware" cody uses and got a little concerned that inflation was hitting pyrex so hard that he couldn't get any then remembered that hydrofluoric dissolves glass lol
Absolutely love a counterintuitive result, the most valuable kind! I really thought they would get duller as the edges with greater surface area would be dissolved more. But that's not what happened...
I think that is what happens, as you erode greater surface area it coverges on edges as the surface availible to dissolve gets smaller, which would make it dissolve more *away* from the edge. Essentially chemically sharpening the edge.
When you said the arrowheads aren't antiques it made me wonder how rare they are 'in the wild' in modern times. Always appreciate your videos and hope you're well. Thanks Cody.
Some places will have more than others, but they're hardly as common as rocks. There are a lot of time periods as well and some are much more rare. Some designs are also harder to find because they're more fragile than others. Edit: in this video he used ones knapped by machine in modern times.
My grandmother lived on a farm in Mississippi growing up in the 30's and 40's. Over the decades she collected hundreds of arrowheads. They had a beautiful display made for them. It was a wooden coffee table with a glass top. Under the glass was a felt lined drawer and they had them all very neatly displayed. Thinking back on it I don't know whatever happened to those arrowheads. Both my grandparents are dead now but I suspect they just left them behind when their house was destroyed by Katrina.
Something similar to what happened to the obsedian: we can do directional etching with KOH on silicon. Some planes of the crystal are more prone to dissolve than other, and some specific structures can be achieved through this.
EDIT: This is awesome because I find a lot of big seam agates that are super hard to clean. Pressure washer wont cut it and Oxalic is too weak to take the rind off. I bet this would work great when diluted for the job. Brilliant sir, great idea! Thanks Cody!
Cody, i have a weird thing i want to see done. Silicon metal when amorphous apprently breaks like glass, thus it should be able to be “knapped” into an arrowhead. I have experience knapping but havent been able to get a large enough piece of silicon to test it. Do you think it can be done?
@@lajoswinkler Due to the wide variety of forms in which silicon comes in, due to various alloys and other compounds, noting it as "silicon metal" is, indeed, useful. Furthermore, while it is not in fact a metal by scientific classification, it IS a metalloid, and is used in many aspects of metalworking industries as a metal, where it is referred to as "silicon metal" for that specificity, eg. in Silumin, the silicon/aluminum alloy group; in Ferrosilicon, the iron-silicon alloy group; Nicrosil and Nisil, nickle-silicon alloys (name differentiation is for positive/negative thermocouple legs, respectively); and more. Fun fact: While it has many properties similar to metals, the reason the name of the element in modern day (going back a hundred years to its official naming) is "silicon" rather than the original "silicium", is because it is elementally closer to carbon and boron than to calcium and magnesium.
Something of note, while the hand-sharpened arrowheads weren't as sharp as the acid-dipped ones, if used for hunting game, they would "stick" better to flesh and fur than the latter if they penetrated causing continuous bleeding, simply because of the jagged and irregular nature of the edge. The acid dipped arrowheads would need more prominent backward facing barbs to achieve the same level of adherance.
Congratulations, this was my 5000th liked video! 👍 I wonder if arrowheads knapped from artificial glass would also sharpen in the acid. It was surprising to me. I would have guessed the acid would round the sharp edges, not make them sharper. I guess the acid attacked everywhere the same, and as the arrowhead got thinner it exposed a fresh edge. Cool result.
I am sitting here in an assay lab at a palladium mine watching this video. . I had to resist going to the HF storage and drumming up my own experiments. Very cool stuff you have going here. Cheers!
Hey Cody. I was wondering if there was any news on the Mars One program. I haven't watched your channel in a while. I'm glad a video finally got recomended to me again and Its good to see you still making content.
I love how u pour the water in acid and you are probably doing this on purpose :D The video about this topic was the reason for me to follow ur content 6, 7, 8, 9 (???) years ago. Still one of the best, much love.
Two jobs ago, hydrofluoric acid was used to write on and etch glass for a college theatrical department. This was sort of a " Safety is Job 42" process. In junior high school art class ( 1976), we chipped out arrowheads from beer bottle glass....that probably wouldn't be allowed now...
How does the permeation in acid effect the ability to further work the piece? Or maybe work the piece, then paint a certain amount of acid on the edges for a crisper clean.
I wonder if Cody ever had to have "the talk" with his parents? Mum - "Son, are you a domestic terrorist or just a mad scientist? We'll accept you either way but you might need help"
Very interesting seeing the difference between those samples; From very far away. HF scares me as much as concentrated HOOH or TATP in larger measures than for which milligrams are convenient
The scary part about HF is not that it will burn you, but that it will poison you. It gets absorbed quickly through your skin because it's such a small molecule. And once inside it will react with the calcium in your bloodstream, causing 2 things to happen: 1. it will lower your calcium to dangerous levels, impairing many functions such as muscle contraction - including the heart muscle, myocardium; and 2. the calcium fluoride precipitates in the bloodstream as little crystals, which will clog your kidneys and give you renal failure.
I have only watched the intro, and I have seen a really interesting detail already i have to bring up. In the fume hood, the power on the surface around all the beakers, is that baking soda? In case of spills to neutralize the acid? Edit: So is lime. Right idea as to why. Is lime needed specificly because of the strength of the acid or possible reactions?
I honestly thought they woul dull in the acid. My reasoning was that the thinner areas, like the edge, would dissolve much faster than the bulk on account of having a bigger ratio between surface area and volume, but apparently I was wrong
I think you are actually right! The chalcedony flint and agate both dulled. I think that obsidian might be a special case since it has some interesting patterns and properties.
@@billcypher8563 hmmmm, it's quite possible that obsidian is more chemically resistant along grain boundaries, which coincidentaly is where it usually fractures
**Casually pans to large jug of HF** Eep! I'm definitely not that brave, but then again, I don't taste-test mercury either. Such a lovely substance, "goes right through gloves" and then "you don't know it but you've already had a lethal dose". I would definitely slip and dump a liter of it on myself.
@@davidsmith7653 Liter and litre are both correct, it's just an american/uk english thing like aluminum and aluminium. Personally, even though in my own language (Italian) it's "litro" which is closer to the UK spelling, I find "liter" much better. It's easier to pronounce and clearer.
@@demoniack81 I mean, it's not like the UK litre is pronounced like the French word. In fact, in the British pronunciation, there's no /r/ at all, neither before nor after the vowel. It's just a schwa.
Noooo! You sicken me... 😁 That Black Rock desert/Delta "obsidian" is indeed extremely tough rock and doesn't act much like an obsidian at all, to knap. I think it's only obsidian in name and perhaps in form, but probably pretty silica poor.
@@theCodyReederOh, I've chased all kinds of knapable rocks around the state and beyond. I've sent samples to the Western Digs labs for XRF identification and their lithic sourcing database. If it knaps and it's in Utah, I've probably seen it and tried it. 😉
This was really interesting, That is one scareeeee acid. Has to be handled with extraordinary care. I have a friend who got a splash on a fingernail and it took the hospital weeks to give him the all-clear.
I wonder if this prossess could be used for extremely sharp and reusable scruples for the medical industry, the acid would eat away the dull obsidian, as well as blood and any flesh, (maybe making it sterile in the process) and it would be repeatable until the obsidian got too small for any use. Although I have no idea if this is safe or even practical for the medical field
I love arrowheads, especially obsidian ones...in 7th grade we went to a Native American historical preservation, there was an older man sitting at a table making an arrowhead out of obsidian with a couple pieces of leather and antler. Me and a bunch of kids started watching him, and they all eventually went to look at other things, but I stood there and watched him the entire time...I dont remember either of us saying a word to each other other than hello. He was finishing it as our field trip was ending, he glanced around, wrapped it in a piece of paper and handed it to me and just said 'shhh'. I gently stuffed it in my pocket and proceeded to hold the biggest secret of my life the entire bus ride back to school, the last hour of school, and the bus ride home before I could have a little freak out about him giving it to me. I pulled it out of my pocket, unwrapped it and marveled at it, it was huge, and sharp, and you could see right through it, totally blew my mind. That was nearly 30 years ago, I still have it, wrapped up safely in a box that I open occasionally when nostalgia gets the better of me.
...now if you'll excuse me, theres a box I need to look at...
I found it, then recorded it, then wrote a song for it, then recorded it, then mixed them, then uploaded it, now I'm posting it...thanks Cody! lol
That's really cool!
There is a guy on UA-cam that does that for videos. All different styles of flint napping
@@Gabriel-nf8eb Thanks, it was definitely one of the better moments of schooling lol
@@christianterrill3503 Yeah I've watched a few, I've got obsidian and flint, but have yet to give it a try. One of these days...
"No! Don't lower me in the acid!...blerglglg"
Hahahah yeah I loved that
I almost choked on my food. Ahahah
Hello, how are you? I am under the water. Ululululu
I came here to make that same quote. Lol!
Yeah, that's going to be memed to oblivion
Every chemistry teacher in the history of mankind: "Always pour acid into water"
Cody: "Don't tell me how to live my life"
I once poured water into oleum. It was quite an exciting experience.
to be honest you should be ok unless you work with oleum or fuming nitric acid.
why?
unless its highly concentrated and a medium to high amount of acid, nothing much happens except for mostly a slight rise in temperature. try that with a lot of oleum and its a different story...
Every good chemist knows it only applies for few acids like concentrated sulfuric, perchloric, oleum. It's perfectly useless rule for other acids. Nothing will happen if you pour water into concentrated nitric or acids made from hydrohalogenides.
Cody is exactly the kind of person I would expect to have a (maybe) 14-year-old bottle of HF just lying around like it's no big deal.
We used to use HF to dissolve quartz that held lode gold nuggets to improve the specimens. Scary stuff even for a Geochemist. We didn't dilute ours though so it worked faster and we could direct it where we wanted rather than just dunking the whole chunk.
In regard to your results, you need to remember that while Chert and Agate are primarily composed of quartz (a silicate mineral), Obsidian is simply rapidly cooled lava which contains many minerals other than silicates and those would resist the acid.
Im terrified to touch the stuff, so i would probably just use hot sodium hydroxide.
fellas he's literally named rockbutcher, i'd trust him
Do you seriously think you can give Cody a lesson in geology. Hilarious.
@@teeanahera8949 Given that I have been a Geologist for longer than Cody has been walking? Yes I do.
Did you ever dissolve any claim-jumpers?
Other comments talking about how dangerous 50% HF is. Me over here just glad he wore gloves when pouring it this time
they do something similar for fishing hooks. Sometimes you will find written on the packaging "chemically sharpened"
Same deal with a lot of college students
Hydrofluoric acid is high on my list of things that I don't want to play with.
Probably a smart idea
Next on Cody's list chlorine trifluoride aka "human kryptonite"...
I did in my scientific career, boy did I take precautions. I also played with a solution that had the warning not to breath any vapor in or spill whatever, it would rupture my red blood cells immediately and I would suffocate. Joy :)
Next time: Can you swim in mercury?
"Of course, the greatest problem is the density of mercury makes it incredibly difficult to immerse yourself. This is why I'm going to be wearing these uranium waders..."
Cody has done the floating in mercury video already, actually. He wore boots, though.
Dipping miscellaneous things into strong acid is a simple yet fascinating idea for experiments. So many possibilities!
Cody really likes playing with the most dangerous chemicals possible LOL
So WE dont't have to do it...! 😉😂
Today we're looking at sarin and ricin, and their etching effects on different containers.
...
Shows ingredients
...
That fan you hear is taking care of any potential fumes, and we are downwind from any major metropolitan area, so we we're safe.
@@cult-of-sporque Neither have etching properties, and neither sarin not ricin are particularly volatile
@@GaiusCaligula234 OK. Instead we're going to use some liquid nitrogen to condense both of them to liquid form, and then mix together within a pressurized vessel?
Our goal today is to find a just-the-right mixture, that allows us to induce a slush-like substance that you can use tp disinfect your chicken coop.
@@cult-of-sporque Son, sarin is liquid in room temperature
Cody Don - this is some of the most absolutely TERRIFYING chemistry I’ve seen you do so far… This is Styropyro territory, but with Fluorine
A before and after weighing would have been interesting to see how much mass the acid removed.
I have a feeling we are watching the training videos of a super villain.
Step 1: extract all the precious metals
Step 2: disolve the 'hero' in acid
Step 3: escape to Mars and live peacefully
Nah Cody is one of the good guy chemnist. There are others way more scary (though also good guys... hopefully... *looks at NileRed and Explosions&Fire)
I love seeing videos like this from you Cody.
I can feel your genuine curiosity about this experiment and it feels like you did this work to figure something out for yourself as opposed to for your audience.
If you ever find yourself thinking "im the only one that would ever watch this", when conceptualizing a video, please dont shelve it. Thats exactly ankles the kind of stuff we love from codyslab.
Thank you for being you.
What does “That’s exactly ankles the kind of…” mean?
The balls on this guy. Hydrofluoric acid scares my pants off!
My chemistry lab TA in college would scold us if we even do much as wrote fluorine ions in our notes. She'd say "You should NEVER be making this ion!" and then told us some horror stories about HF.
Then there's the geology grad students. I remember walking past the geology lab once and I saw a grad student in there nonchalantly eating her lunch on a table below a shelf with a bottle labeled "hydrofluoric acid, contact poison" and a skull and crossbones. Only geologists have the balls for such shenanigans. Hey... isn't Cody a geologist? See? I told you. They fear nothing!
Loved this video. The sharpening was not what I expected. Very fascinating.
Same here! It must be due to the specific way that obsidian forms and its specific composition, where it shears to the monomolecular level and tends to knap in thin sheets, because I expected the thinnest part to dissolve faster than the flat of it, but it didn't!
I was just about to eat lunch, after being sat in front of an instrument at work for 6 hrs straight, looking for something to watch while I eat. Seeing a new Cody's Lab video made me feel a lot better 😊
As an archaeology student, this is both horrific and fascinating
they are modern recreations of arrow heads
I know don't worry! Obviously Cody's a lil smarter than that xD
As a chemist, it's just horrifying. This dude's lack of....just about every precaution is alarming.
Makes me think of the myths of when the Inca could melt and shape stone with a solution they poured over the boulders
@@refluxcatalyst7190 What precautions was he missing? Proper "glass"ware, had a nice bed of lime, wore gloves, has a fan? Honestly y'all armchair chemists have probably never even set foot in a real lab lol.
You and NileRed were the people who made me have interest in Chemistry in high school...
Thanks for the videos...
As a flint knapper this is interesting to me. One of the most arduous parts of replicating certain blade types like danish daggers is that they have to be ground to a perfect convexity. Perhaps this could greatly expedite the process!
But if you're doing it with modern methods, mightn't you directly use modern materials?
@@unvergebeneid Who knows how long people having been using acid to shape stone? Maybe this could explain some of the incredible stone work of the ancient egyptians like those hollow vases? Still no good theories on how those were made.
Choose another acid than this if you can, corrosive+contact poison+deadly vapours+rapidly skin penetrative isn't a great combination.
@@frysebox1 Yeah I'm a bit scared of hydroflauric acid ever since watching breaking bad haha. I wonder how effective milder acids would be. Would lye do anything to a rock? It's easy to make with campfire ash. Dannish daggers were ground on a granite slab with water... i wonder if using lye water instead would speed things up at all. Regular water takes like 20-30hrs of grinding.
@@wcomalley HF (with a pKa of +3.2, the less the more acidic) is by no means a very strong acid, it just has the strange characteristic of dissolving silica-based materials like glass. sulfuric (pKa of -2), hydrochloric (pKa of -7), or nitric (pKa of 'i don't remember') are stronger acids than HF, that is because fluorine is so reactive that it bonds hydrogen a little to strongly. Also, HF is very, very toxic, it reacts with calcium ions and causes cardiogenic shock and cardiac arrest if it comes into contact with the skin, It's so bad that pretty much every professional chemist I know avoids as much as humanly possible..
this acid can dissolve so many things but when it comes to plastic it's like 'uh i don't know what to do' i find that so funny
I thought that part of breaking bad was fake but apparently not
@@OmniversalInsect Nope, many weird solutions are stored in plastic. I was always kinda amazed by that working with them.
Hcl is the big boomer of acids
Ain't gonna react with those new 'plastics'
@@OmniversalInsect the fake part is that they have huge jars of this extremely dangerous stuff just sitting in a high school lab's storage room.
acetone, ether and chloroform can dissolve/attack many plastics, but do nothing to most inorganic materials
My heart sank a little until you said they wasn’t true Indian arrowheads lol but your friend did a great job making those I found a few real ones here in Indiana close to my house I found one little white one I think it’s a bird point used by Indians for hunting birds very cool I used to love going arrowhead hunting thanks for sharing Cody love watching the videos
The guys over at good and basic have some great content. Primate forging, the spinning wheels and whatnot, too. (The philosophical discussions are interesting as well). Glad to see the interactions between channels like this.
@@Grandwigg wow I never knew one could forge primates! Crazy! (I am just having a little joke)
That’s all really cool though sounds like their channel is right up my alley thanks mate
That's so cool. I'd love to find one
My heart sank even more because being the eurocentric prick that I am, I thought these might be neolithic! I somehow didn't put together that in the US, authentic stone arrow heads must be much more common and only a couple centuries old.
Imagine if they had access to and could have worked with HF acid for sharpening their hunting arrow tips... lol... I found a few when I was a kid visiting my grandfathers farm in Burlington, Ontario... that was neat for a kid to find.
I would love to see a microscopic view of the edges before and after. Maybe even an atomic view if possible.
I really appreciate the uploads Cody! I don't care what you upload, it's always interesting and I'll always enjoy!
Very cool experiment and demonstration. I think the "snowflakes" in the obsidian may be volcanic ash that fell in the molten obsidian flow. Even though the materials of obsidian, agate, and flint/chert are especially suitable for knapping stone tools because of their characteristic conchoidal fracture, they are formed differently. Many people probably do not know this regarding stone tools, but for a razor sharp cutting blade our ancestors used blades similar to the un-knapped piece that sliced the paper best. Even though knapping could thin and nicely shape arrow heads and other tools, it's more difficult to get a continuous sharp edge that way.
Dang, you should have written the date on that arrowhead…
Although it’ll probably be just an arbitrary number when someone discovers it in an asteroid 12 billion years from now, long after the earth has been annihilated
I find these stone videos way more interesting than I thought I would. I have always wondered about rose rock. Its a weird stone.
Rocks can be addictive ^^
When the video started i immediately thought about the typical "glassware" cody uses and got a little concerned that inflation was hitting pyrex so hard that he couldn't get any then remembered that hydrofluoric dissolves glass lol
Absolutely love a counterintuitive result, the most valuable kind! I really thought they would get duller as the edges with greater surface area would be dissolved more. But that's not what happened...
I think that is what happens,
as you erode greater surface area it coverges on edges as the surface availible to dissolve gets smaller,
which would make it dissolve more *away* from the edge.
Essentially chemically sharpening the edge.
When you said the arrowheads aren't antiques it made me wonder how rare they are 'in the wild' in modern times.
Always appreciate your videos and hope you're well. Thanks Cody.
Some places will have more than others, but they're hardly as common as rocks. There are a lot of time periods as well and some are much more rare. Some designs are also harder to find because they're more fragile than others. Edit: in this video he used ones knapped by machine in modern times.
My grandmother lived on a farm in Mississippi growing up in the 30's and 40's. Over the decades she collected hundreds of arrowheads. They had a beautiful display made for them. It was a wooden coffee table with a glass top. Under the glass was a felt lined drawer and they had them all very neatly displayed. Thinking back on it I don't know whatever happened to those arrowheads. Both my grandparents are dead now but I suspect they just left them behind when their house was destroyed by Katrina.
@@Camroc37 Looks like not knapped by a machine, but knapped manually by a friend who presumedly didn't mind the experiment.
Something similar to what happened to the obsedian: we can do directional etching with KOH on silicon. Some planes of the crystal are more prone to dissolve than other, and some specific structures can be achieved through this.
So glad you are still uploading. Been a long time fan. Can't wait for more!
Your videos sometimes answer questions, I never thought I wanted to know.. cheers bro🍻
So you have found out how to acid sharpen certain stones! I love it!🤝👍👍
EDIT: This is awesome because I find a lot of big seam agates that are super hard to clean. Pressure washer wont cut it and Oxalic is too weak to take the rind off. I bet this would work great when diluted for the job.
Brilliant sir, great idea!
Thanks Cody!
You can buy a 3% HF solution at Walmart. It’s sold as a rust stain remover.
@@theCodyReeder You're the man!
@@theCodyReeder hey. Man. Make. A. Video. On. (Interstellar. Space. ) And. The. Fermi. Paradox. Rite. Now. Do. That. Video. Now.
Cody, i have a weird thing i want to see done. Silicon metal when amorphous apprently breaks like glass, thus it should be able to be “knapped” into an arrowhead. I have experience knapping but havent been able to get a large enough piece of silicon to test it. Do you think it can be done?
based on my experience with amorphous Si, I would expect that you should be able to.
Silicon is not a metal. Even if it was, it's unnecessary to mention it's a metal.
@@lajoswinkler You may not be a metal but you sure are dense
@@lajoswinkler Due to the wide variety of forms in which silicon comes in, due to various alloys and other compounds, noting it as "silicon metal" is, indeed, useful. Furthermore, while it is not in fact a metal by scientific classification, it IS a metalloid, and is used in many aspects of metalworking industries as a metal, where it is referred to as "silicon metal" for that specificity, eg. in Silumin, the silicon/aluminum alloy group; in Ferrosilicon, the iron-silicon alloy group; Nicrosil and Nisil, nickle-silicon alloys (name differentiation is for positive/negative thermocouple legs, respectively); and more. Fun fact: While it has many properties similar to metals, the reason the name of the element in modern day (going back a hundred years to its official naming) is "silicon" rather than the original "silicium", is because it is elementally closer to carbon and boron than to calcium and magnesium.
@@lajoswinkler Every element on the periodic table after hydrogen is a metal.
After watching those arrowheads being made, I really needed a knap.
Love your uploads Cody, keep at it, we all appreciate them very much
CODY! My favorite most humble smart guy!!!
Really good observational science that does what we would want to.
Rock on Cody!
Something of note, while the hand-sharpened arrowheads weren't as sharp as the acid-dipped ones, if used for hunting game, they would "stick" better to flesh and fur than the latter if they penetrated causing continuous bleeding, simply because of the jagged and irregular nature of the edge.
The acid dipped arrowheads would need more prominent backward facing barbs to achieve the same level of adherance.
It's allways great when Cody brings us knowledge!
I like the prank on the archaeologists. Was aware of an old trick for re-sharpening a dull file in sulfuric although never tried it myself.
Congratulations, this was my 5000th liked video! 👍
I wonder if arrowheads knapped from artificial glass would also sharpen in the acid. It was surprising to me. I would have guessed the acid would round the sharp edges, not make them sharper. I guess the acid attacked everywhere the same, and as the arrowhead got thinner it exposed a fresh edge. Cool result.
I am sitting here in an assay lab at a palladium mine watching this video. . I had to resist going to the HF storage and drumming up my own experiments. Very cool stuff you have going here. Cheers!
Such a transformation is neat Cody. I like the way the look how they would nature
Awesome video thanks! Cody you are amazing I love your videos, I love your sense of humor. And I extremely respect your morals.
I was a kid at the tail end of the acid and stone washed jeans era. You just acid washed stones, everything comes full circle eventually.
Looks like the most hard-core tea ever.
Hey Cody. I was wondering if there was any news on the Mars One program. I haven't watched your channel in a while. I'm glad a video finally got recomended to me again and Its good to see you still making content.
You have fantastic chopstick skills.
Great video Cody. Really interesting.
I love how u pour the water in acid and you are probably doing this on purpose :D
The video about this topic was the reason for me to follow ur content 6, 7, 8, 9 (???) years ago.
Still one of the best,
much love.
Two jobs ago, hydrofluoric acid was used to write on and etch glass for a college theatrical department. This was sort of a " Safety is Job 42" process.
In junior high school art class ( 1976), we chipped out arrowheads from beer bottle glass....that probably wouldn't be allowed now...
15:15 Show this section to your geologist friends to distract them while you wind up and aim with your wooden cudgel.
Just putting the edge in the acid would be a cool way to sharpen it, some experiments would be cool
An EXTRAORDINARY vid which was entertaining AND informing me !
NOTHING more i could ask for....
THX++ Cody !
4:50-4:55 is when he finally loses his sanity.
the foggy effect created on the obsidian is beautiful
Being a flintknapper, I will say that this is one way atleast to get rid of that pesky hinge or step fracture, along with all the flaking as well lol.
try melting some obsidian and flint and glass and agate together and maybe you’ll get a cool layered silica material
I find in sort of ironic that one of the strongest acids cannot dissolve plastics. Shows you how hard to break down plastic is
Love all your videos man! Wonder eho will find your arrowhead in the future?
That's what gave the edge to the Yellowstone area acid pit pre-war surgeons... probably.
Imagine if someone finds that arrowhead in a couple hundred years.
How does the permeation in acid effect the ability to further work the piece?
Or maybe work the piece, then paint a certain amount of acid on the edges for a crisper clean.
I wonder if Cody ever had to have "the talk" with his parents?
Mum - "Son, are you a domestic terrorist or just a mad scientist? We'll accept you either way but you might need help"
How do we know HF is scary? Cody actually wears protection.
@4:52 like 'who framed rodger rabbit' and the 'dip' to melt cartoons. and the big rubber gloves.
I went the extra step and watched this on acid, groovy.
That ending is gonna confuse TF out of some future archeologists when they dig it up if it ever comes to it.
This video is pure anxiety! That acid is scary stuff...
Very interesting seeing the difference between those samples; From very far away. HF scares me as much as concentrated HOOH or TATP in larger measures than for which milligrams are convenient
The scary part about HF is not that it will burn you, but that it will poison you. It gets absorbed quickly through your skin because it's such a small molecule. And once inside it will react with the calcium in your bloodstream, causing 2 things to happen:
1. it will lower your calcium to dangerous levels, impairing many functions such as muscle contraction - including the heart muscle, myocardium; and
2. the calcium fluoride precipitates in the bloodstream as little crystals, which will clog your kidneys and give you renal failure.
I love the strength/weakness aspects of almost all elements... Yeah it'll melt and absolutely destroy this, but it can't touch this. Except ClF3
I have only watched the intro, and I have seen a really interesting detail already i have to bring up. In the fume hood, the power on the surface around all the beakers, is that baking soda? In case of spills to neutralize the acid?
Edit: So is lime. Right idea as to why. Is lime needed specificly because of the strength of the acid or possible reactions?
Holy crap those are sharp!
I honestly thought they woul dull in the acid. My reasoning was that the thinner areas, like the edge, would dissolve much faster than the bulk on account of having a bigger ratio between surface area and volume, but apparently I was wrong
I think you are actually right! The chalcedony flint and agate both dulled. I think that obsidian might be a special case since it has some interesting patterns and properties.
@@billcypher8563 hmmmm, it's quite possible that obsidian is more chemically resistant along grain boundaries, which coincidentaly is where it usually fractures
This is what I thought too
**Casually pans to large jug of HF** Eep! I'm definitely not that brave, but then again, I don't taste-test mercury either. Such a lovely substance, "goes right through gloves" and then "you don't know it but you've already had a lethal dose". I would definitely slip and dump a liter of it on myself.
And if you were from a civilised country you'd dump a litre of it on yourself :)
@@davidsmith7653 We've only been trying to metrify since 1875, we're working on it. Maybe give us a break on spelling in the meantime.
@@davidsmith7653 Liter and litre are both correct, it's just an american/uk english thing like aluminum and aluminium. Personally, even though in my own language (Italian) it's "litro" which is closer to the UK spelling, I find "liter" much better. It's easier to pronounce and clearer.
you are safe if you know what you are doing - people handle dangerous chemicals all the time - like filling gas canisters, diluting bleach, ammonia...
@@demoniack81 I mean, it's not like the UK litre is pronounced like the French word. In fact, in the British pronunciation, there's no /r/ at all, neither before nor after the vowel. It's just a schwa.
Cody drowning rocks killed me lmfao
I LOVE when a notification comes on from Cody! You make such great videos! 😊😊😊
4:50 I think this guy just snapped into the evil mad scientist everyone was expecting him to become.
Hello!I havent watched this video yet,but your videos inspired me to get into chemistry!I really thank you for that!
Lol! I love you adding water to the acid. I remember an old video you made on the subject. There's no way that wasn't on purpose 😅😅
awesome video, i thought before the results it would actually dull the edges as they are the thinnest part, instead it sharpened them!
Imagine seeing your lab report pinned with this arrowhead and a note "You have failed this class"
Noooo! You sicken me... 😁 That Black Rock desert/Delta "obsidian" is indeed extremely tough rock and doesn't act much like an obsidian at all, to knap. I think it's only obsidian in name and perhaps in form, but probably pretty silica poor.
I like how you correctly identified its source.
@@theCodyReederOh, I've chased all kinds of knapable rocks around the state and beyond. I've sent samples to the Western Digs labs for XRF identification and their lithic sourcing database. If it knaps and it's in Utah, I've probably seen it and tried it. 😉
Thanks for being nice when I ran into you at the store lol. I appreciate what you do
Am I the only one who always reads "cody slab"? 😂
A very cool experiment!!!
This was really interesting, That is one scareeeee acid. Has to be handled with extraordinary care. I have a friend who got a splash on a fingernail and it took the hospital weeks to give him the all-clear.
I was wondering if you could recover any important minerals from a used water filter?
If Cody’s wearing gloves you know it’s proper hazardous!!
I think that method is the same as sharpening a file. Machinists have used acid for years.
I wonder if it would be possible to use acid to make a sword or something. Like selectively eroding parts away of metal or something similar
Would a mixture of a weak acid, say citric, and a fluorine salt be able to dissolve these?
But can you dissolve hydrofluoric acid in arrowheads?
I wonder if this prossess could be used for extremely sharp and reusable scruples for the medical industry, the acid would eat away the dull obsidian, as well as blood and any flesh, (maybe making it sterile in the process) and it would be repeatable until the obsidian got too small for any use. Although I have no idea if this is safe or even practical for the medical field
@4:48 LOL... that reminded me of the Mr Bill skits
I first read hydrochloric acid, and went "eh, limestone arrowheads, I suppose."