Dissolving Arrowheads with Hydrofluoric Acid

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...

"No! Don't lower me in the acid!...blerglglg"

Every chemistry teacher in the history of mankind: "Always pour acid into water" Cody: "Don't tell me how to live my life"

Other comments talking about how dangerous 50% HF is. Me over here just glad he wore gloves when pouring it this time

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.

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.

they do something similar for fishing hooks. Sometimes you will find written on the packaging "chemically sharpened"

Hydrofluoric acid is high on my list of things that I don't want to play with.

Dipping miscellaneous things into strong acid is a simple yet fascinating idea for experiments. So many possibilities!

As an archaeology student, this is both horrific and fascinating

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.

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!

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 😊

Cody really likes playing with the most dangerous chemicals possible LOL

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.

Loved this video. The sharpening was not what I expected. Very fascinating.

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!

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

I really appreciate the uploads Cody! I don't care what you upload, it's always interesting and I'll always enjoy!