Light Bulb in Hydrofluoric Acid (HF)
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- Опубликовано: 18 ноя 2014
- We dunk a glowing lightbulb in HF - an acid famed for being disagreeable with glass.
Discuss on Brady's subreddit: redd.it/2mrnyw
Featuring Martyn Poliakoff and Neil Barnes.
Hydrofluoric Acid and a bulb.
More chemistry at www.periodicvideos.com/
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From the School of Chemistry at The University of Nottingham: bit.ly/NottChem
Periodic Videos films are by video journalist Brady Haran: www.bradyharan.com/
A run-down of Brady's channels: bit.ly/bradychannels
Music by Alan Stewart. 
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If it breaks it's physics. If it dies it's biology. If it explodes it's chemistry. If it turns on you it's sociology.
If it lies to you it is political science.
It it never does what you want it to it's computer science.
If it causes school shootings it's Minecraft and Tetris.
if it tells you deserve to be poor it's economics
if it tries to peek into your brain it's psychology
0:26: A small exposure can cause a "heart attack" (technically, an arrhythmia) because the fluoride ions create insoluble salts with calcium and magnesium, depleting blood calcium levels. This can cause hypocalcemia and hyperkalemia which lead to cardiac arrhythmias.
Thank you for explaining, i was going to ask how can a small exposure lead to a heart attack.
Many years ago, you could buy a glass etching compound from craft stores. There was no warning of the consequences of exposure, just instructions to thoroughly irrigate any exposed skin. This may explain why by the age of 40 I experienced arrhythmia (and to this day) requiring daily medication.
The active ingredient was hydrofluoric acid.
MrVeryCranky I wonder if you can sue the manufacturer... There must thousands of other people who are going through the same problems
Complete nonsense. MgF2 and CaF2 are soluble at the concentrations of Mg and Ca found in the body.
A lethal dose is 5-10 grams of fluoride. Lower doses cause nausea. Chronic poisoning with low doses causes bone deformations.
@@jpdemer5 5 grams of fluoride isn't really that much when we're talking about a liquid spill. Unfortunately, HF readily penetrates skin, so in severe incidents, amputation of limbs is required.
Even if you don't die, the fluoride messes with your metabolism and blocks enzyme functions. You don't have to render Mg or Ca insoluble to cause issues. Drastically slowing down reaction rates in your metabolism is definitely enough to get you into trouble.
As a chemist who has been repeatedly using HF in the past two years, I am surprised they chose to use sodium carbonate to neutralize it. Not only is sodium fluoride still an unsafe chemical, as the fluorine is still weakly bound, but the bubbling can lead to an HF/NaF mist.
I, personally, use a large amount of water with some calcium chloride or nitrate dissolved in it. There's no bubbling, all the fluorides precipitate as harmless calcium fluoride, and the dilute acid resulting from it can simply be disposed of as any aqueous acidic solution. (although we still use a separate waste container labelled "Hydrofluoric acid waste" for it).
In general, I think calcium salts should always be used in neutralizing HF.
RedInferno112
Because calcium hydroxide has very low solubility in water, and is also corrosive anyway. Plus, it is sold as a fine dust, which I really don't like to handle.
piranha031091
Solubility is irrelevant here. Calcium hydroxide will happily react with hydrofluoric acid to form calcium fluoride and water. After all, hydrochloric acid will react with calcium carbonate, yet that has low solubility. Calcium fluoride is a much safer byproduct of the nutralisation of HF because it is so insoluble.
breakbumper
Solubility IS relevant, since it means you won't be able to dissolve much of it in the solution you prepare for neutralizing the HF.
It would be irrelevant if applied as a powder directly on the HF.
This is not what I do : I use a large beaker filled with the calcium solution in which I dip all the contaminated labware.
breakbumper If the reaction product is insoluble isn't there a risk the reaction won't go to completion, it would get passivated by a thin layer of the fluoride salt.
I vaguely recall if you put calcium carbonate in sulphuric acid you got a disappointing short fizz then the reaction was stopped by a barrier layer of sulphate
piranha031091 Not if you intend to put solid calcium carbonate in the acid. The acid will happily react with it.
Neil is the guy I wanna be when I grow up.
When Neil breathes is Sarin neve gas , it kills the Sarin instantly.
+VIIXM3 Neil is what you get when you combine Igor and Chuck Norris.
+VIIXM3 Neil looks like the type of guy who used to work at a secret government facility but now is placed at somewhere he will not draw much attention and he is supposed to keep quite about his previous work. That's why we never see him speak.
TheDarkdrawn
The chemist protection program
TheDarkdrawn and they call him in when they have a problem so he keeps inconspicuously sneeking away
I love the smell of SARAN in the morning
This man looks like science.
This was said in the other video.
+A Potato what?
+HermanoLaPotato he is science.. lol
unoriginal
Only heard this 500 times in each of his videos
The prof. definitely looks like someone who would wake up thinking "What would happen if I shoved a lightbulb in some Hydrofluoric Acid?"
I have a theory as to why a neat break was formed at the point where the liquid meets the air.
I think it's because at the point where the lamp is exposed to air will be the hottest, as there is no liquid to carry the heat away. Only air, which is a better insulator.
So just where the liquid meets the air, you have an increased reaction rate due to the heat.
I think that if the bulb was off, then the glass would have been dissolved more evenly.
I may be completely wrong, but that's my theory.
Would appreciate any input on what others think of this.
Seems perfectly plausible to me! There would likely be some strain along the temperature gradient and eventually the material just couldn't hold it.
If the bulb was off, wouldn't the inherent strain in the material fracture it along the line where thin transitioned to thick?
One way to find out, I suppose...
I was thinking along those lines aswell, I think that would have been a major part in it.
I think that the tension(inherent) in the glass, would make it crack neatly because the weakened area was like a ring around the bulb. Not unlike cutting in glass.
Another way to test it could be to put the bulb at a different angle into the HF.
Nikolaj Lund Madsen I like your idea about submerging the bulb at a different angle in the HF. That would certainly determine if it was due to the manufacturing of the glass, or the angle of submersion.
It would be good to see a range of experiments. All using the same strength of solution, and same brand/batch of bulbs.
Maybe they could do submerged straight and angled whilst off in solution, and then submerged at an angle whilst on. This way there would be more control and something to act as a base reference. This way, in total four experiments would be executed (including this one).
I was thinking temperature gradient as well. Expansion and all that.
Old chemistry professors never die, they just smell that way.
Here proving that experiments don't necessarily need to involve explosions and colour changes to be stunning.
Do this with a "prince ruperts drop". Tail or bulb first.
Excellent idea! I really want to see that!
I second this motion, but not the mess it might make.
It would be funny if it doesn't dissolve. It's that hard. Just kidding, of course it would dissolve. It would take some protection around it though. HF acid could go flying along with shards of glass.
Note to self: In every circumstance, remain at all times, no lees than 1000 meters away from any and all Hydrofluoric Acid.
@cgdermot *LeEs.*
Well hello there Mr. Jim! Nice to see you!
My father used to work as a chemical engineer before he was a nuclear physicist and he worked with a man who got a little drop of HF on his face and minutes later suffered a nasty stroke, which then brought about the ensuing heart attack. This even with all of the proper safety gear on, but back then not everyone had full face shields and he had on a pair of lab glasses. He did survive but he was never able to return to work.
Thank you to the members of the chemistry department of the University of Nottingham for all of the wonderful videos that you produce. I watch these now and fondly remember the countless hours that I had spent with my father doing some similar (and some of the same) experiments in the lab. Happy Christmas to you all and best wishes for a Prosperous New Year in 2015 - I look forward to the new videos to come!
you guys should do a video on fluoroantimonic acid
Yea I've been looking for a video on that... For some reason NO ONE has done it.
that's because it's nearly impossible to contain and too dangerous for human use
+rojva29 yes I know, Teflon is basically the only thing that can contain it. It would be dangerous but that's what makes it fun.
The reason may not be, that its so dangerous (There are alot of chemists with proper safety accessories), the true reason may be that the acid is really REALLY hard to get.
a ph balance of - 25
HF was always one of the most worrying compounds I've ever worked with professionally (for etching of InGaAs DFB chip wafers), even compared to the others I've had the pleasure of dealing with (Arsine, phosphine, hydrogen sulphide, TMI, DEZ, TMG, white phosphorus, aqua regia...). The only substance that came close to worrying me in any real way was Bromine, it's as though you can see the evil in the vapours as they pour down the bottle on standing in a fume cupboard. We had a dedicated HF response team to deal with accidents and were required to carry calcium gluconate gel at all times, even at home!
I would rather deal with elemental bromine any day rather than HF, and I have made both. And I know of the safety and health risks of both.
I'm actually not even sure if HF would scare me more than Phosphine. Though I'd like to avoid both as best as possible.
Yup was that a Boston Lasers by any chance? Yup the gases fed to the MOCVD machine were pretty horrible chemicals, toxic,corrosive, spontaneously combustible, or all at once. Generally they were diluted in neon gas but still 😲😲😲. Once the PH3 bottle became almost disconnected from the manifold and leaked causing a total evacuation. Thankfully the under pressure safety mechanism tripped and prevented extremely costly damage to the chip baker. 🤓
Thank you for your tenacity and perseverance Neil! I hope the other Senior Chemists really appreciate your fortitude!
I hope I never have to work with HF. A chemistry professor of mine once told me a story about his own personal experience with it. He inadvertently dipped his fingers into a very dilute HF solution, for "barely even a second or so", and ended up losing the fingernails on his thumb and index fingers as a result, besides being put into what he said was the worst pain he'd ever felt.
I think HF destroys nerves, so in theory, he shouldn't have felt pain.
***** I'm pretty sure the nerves are damaged by third degree burns, not overstimulation.
hippiechickie18 The process of destroying a nerve is painful itself. And it's the last thing you ever feel with that nerve.
Its true it destroys nerves it denatures proteins and had huge toxicity level that could give you a heart attack at the touch of it. Its messes with your bones which produce a lot of things blood cells the lot.
Can you help me? Is hydrofluorosilicic acid the same as hydrofluoric Acid? if so, why is it used in our water supply? its toxic right?
4:20 Epic voice crack
How dare you torture my men. First you buy them as POWs from some sick market and then you do this. Despicable
Captain Lightbulb . Scary light bulb 😳
No offense sir, your men tend to crack under pressure.
I once popped a lightbulb, on purpose.
JustAnotherPanzer GASP
Captain Lightbulb I could smell the burned wires from a few centimeters away...
After years and years, yes, we still would love to see formulas. Thank you.
When I was in university, I had a summer job in the quality control lab of a cement factory in the UK.
This was in 1969, and we routinely used HF as a reagent. In platinum crucibles, if I recall correctly... I don't remember exactly what test we were doing, but I assume it was something to do with dissolving out the silicate component of the cement.
Nobody seemed especially scared of the stuff, apart from the standard lab precautions for strong acids.
Guess health and safety standards weren't so stringent back then...!
Fortunately there was never an accident... during my tour of duty, at least....
Wow. I hope to see more of these experiments in the future, but stay safe everyone!
I did experiments using HF at the university. Everyone was crazy paranoid about it and there was extreme safety precautions - including mandatory safety lecture, keycard access and mandatory announcements to the whole area every time the HF was out and in use.
DTU? What kind of research?
ABOlsen69666 Aalborg University. It was a postgraduate project, where we tried to show electroluminescence in pourous silicon. We used HF to produce the porous silicon.
Brady, thank you, Neil, & the Prof for yet another great video.
I live these videos. There's always a wealth of knowledge, and you just cannot find this kind of instructions and entertainment anywhere else
Thanks
Dear Professor Poliakoff,
Many thanks to you and your team for the wonderful und always very interesting videos you post on RUclips.
I have a question concerning the experiment with the light bulb in hydrofluoric acid.
Could the neat crack in the bulb not be caused by the temperature difference between the free part and the submerged and thereafter 'liquid cooled' part of the bulb? It would be interesting to see if the same thing happens even with a light bulb partially submerged in simple water.
Yours sincerely,
Luca Cettuzzi
So, hypothetically speaking, if I were to dispose a body i should use HF.
hypothetically of course...
+Tom DuBois You'd probably be waiting a very long time for the body to lose recognizability.
+Tom DuBois if you're willing to watch it there's a doc on YT about some serial killer who had a bunch of bodies melting away in drums, pretty disturbing. there's also an episode of breaking bad that will give you more info on this subject lol.
Hipotetically, HF is hard to get and too dangerous to handle, i'll use a cincentrated aqueous solution of NaOH instead, because i'ts a lot cheaper and relatively less dangerous to handle and still can dissolve a body with no problem
+isSHEEPMANimmortal Dahmer?
Awesome stuff. This is why I loved Chemistry at school.
My physics teacher once got hydrofluoric acid on his finger...
The acid was immediately absorbed into his finger. Within days, the entire end of his finger had turned black, and a doctor suggested injecting a basic solution throughout his finger to neutralize it. He hates needles, so knowing this was the only fix, he just waited it out. Eventually all of the acid went to his bone and was neutralized. He's about 60 years old and still has all of his fingers, so I guess it worked.
"Even small exposure to skin might cause heart attack, I really want to experiment with it".
It’s the natriumoxalate that will give you a heart attack, that is used when your skin is exposed to HF
HF reacts with calcium very very strongly, that’s why your skin is starting to turn black if you don’t treat it immediately it will start to spread
Most feared acid: Hahahh
This guy: Let me put some electricity in it for fun.
Most feared acid: Gulp
the light bulb cut right where the acid stopped, that is very cool guys, keep it up!
I wondered if this was the stuff I had to handle in military, because of the whole _"One drop on your skin can kill you"_ since that's what we were told too. But I looked it up and it was *HCN* that we had tiny vials of, in case of some form of emergency... can't recall what, since it was over a decade ago. It's not fun to handle dangerous chemicals, so I fully understand Neil's concern here.
I'm curious on how HF in contact with skin will cause a heart attack? anyone?
It reacts with calcium in the blood. Calcium ions are used by the body to generate action potentials (electrical pulses) hence nerve function in vitally important organs such as the heart may become disabled.
The HF passes through the skin and the fluoride (F-) anions react with calcium (Ca2+ cations and precipitate out as the insoluble calcium fluoride (CaF2). This drop in calcium levels wreaks havoc on the functioning of your heart and nervous system. (nerves send impulses by pumping ions in and out of the cells)
That's some pretty interesting stuff. Thanks guys! :)
the fluorine in HF dissociates and binds with free calcium and magnesium ions in the blood stream. in high concentration mixtures (50% and above) the lethal dose is really quite low (7ml of anhydrous HF is enough to bind up all the calcium ions in the average adult male), but even low concentrations can have an effect, if 1% of our body surface area is exposed (this causes a pocket of this hypocalcemic and magnesmic state to follow along the blood stream and cause a similar result to a more significant exposure
) (1% of your BSA is roughly equivalent to the palm of your hand)
PeopleHateMyOpinions who is also a terrible Grammar Nazi sounds like something Walter White would use
You should do some experiments with fluoroantimonic acid.
It too rare and too hard to contain. No one has gotten enough to do anything close to this.
Or they could make azidoazide azide. That's fun
It's so corrosive that even filming it is difficult. The fumes alone would destroy the camera and anyone close to it.
The production values on these videos are first rate. They are a delight to watch.
As a slo-mo guy, Brady is very aptly named.
I adore this channel. Makes me want to go back and take my biochem degree all over again.
0:39 Yes, I've figured out why Neil is expendable. Incidentally its also the same reason you do not ever allow him to speak on camera. There's only one logical conclusion: Neil is Australian.
This is the stuff Walter White used to get rid of bodies wasn't it?
Say my name
It's the stuff used in season 1 of Breaking Bad to dispose of a body, yes. Not sure if you mean the character or the real person.
jinno11 Heisenberg.
No, it's the stuff Pinkman used.
I have no clue why Walter's school had that in their supply cupboard
why is your voice so calming
Best soundtrack choice possible!
Should use concentrated HF next time
HF is extremely dangerous. One drop on your skin and your bones are doomed. You can never be too careful when dealing with it.
There was an accident in a Chinese high school. A chemistry teacher arranged an experiment session for students to play with HF (I know, WTF?) without proper protection (again, WTF?). Some students accidentally dropped some HF on their hands and the teacher was like "that's ok. Just wash with water you'll be fine" (Whaat?). It was not until 36 hours later that those students were sent to a hospital. The best time for treatment had already been past by then.
eeeeh. I don't know about one drop and you're *doomed*. But certainly requires a trip to the hospital and immediate action, not to mention necrosis and extreme pain. But one drop won't kill or permanently injure you. The margin for error is pretty slim though, especially if you don't get calcium glutamate on you right away.
xtamared Of course I did't mean it can doom all of your bones or doom you as a whole person. It depends on the amount of HF you are exposed to. But at least the tissues and bones in the immediate area of exposure will be ruined. F- will bond with all Ca2+ in your bones and form insoluble calcium fluoride (hence ruining your bones). That's why the treatment of HF poisoning always involving calcium gluconate.
It doesn't matter what concentration the HF solution is. And less informed person would assume it is safe to play with low concentration HF. That's why it's so dangerous.
xtamared from what I was informed by my Chemistry coordinator is that it's a sharp initial pain then pretty much no pain because the HF kills the nerve endings quickly. The HF then begins degradation of the nervous system caused by the Calcium ion pumps that are on the axon terminals, interfering with pre and post synaptic transmission.
Cam M sorry, clarity. HF binds to the Ca2+ ions that travel through calcium ion pumps.
Though I could be wrong about this...
HF, the stuff of nightmares....
Man that clean cut of the bulb is really cool
I've been on a chemistry binge, and was wondering while watching a video "why doesn't glass react with anything?". After 15 minutes I have read an article and watched a video demonstrating it. The internet is an amazing thing!
"went well.. didn't explode"
Dear prof, those are mutually exclusive! If it went well, something has to explode!
But only if you preceded the experiment with the magic words, "Hold my beer"... :)
Thedutchjelle You also have to be wearing the safety tie (see colin furze)
Not a single idea on why the glass broke that way? No actual physicists here? I'll take a crack at it (not a physicist). The HF dissolved a lot of the glass away on the bottom, thinning it out. The heat from the filament combined with the heat of the reaction caused it to expand - whereas the glass on the top, still thick, could absorb more heat energy and didn't expand as much. The glass broke at the line of thinning, and stayed in tact where it was thicker.
Differential cooling... you have this intense heat generating bulb sat in a liquid, gets thin enough to where the smallest pulsation causes it to go pop, and due to how glass fractures thats why its not a perfect ring
The most charismatic scientist I'll ever admire
Love the experiments on this channel
Call themselves chemists yet dont know that borosilicate glass (lightbulbs, beakers, test tubes) is resistant to HF. The only thing I am supprized about is that it got through as fast as it did.
No glass is containing silicate of any type is resistant to HF but some react very slowly and some react fast.
so how does it trigger heart attack instead of just burning you?
maybe it goes in your circulatory system, wich...you know...leads to the heart
Because it leaches calcium from your bones and system. Calcium is used as part of the signalling systems in your body. HF is pretty much the devil's piss.
Yeah, I had to look that up, too. Apparently, it dissolves through your skin until it gets to your bloodstream, at which point it interferes with your body's ability to utilize calcium. Calcium, by the way, is extremely important to generating nerve signals, so without it, your nerves stop working--including the ones that keep your heart beating. Hence, heart attack.
Hydrofluoric acid is fun! :D
IceMetalPunk Yeah when I worked in a univ. Maintenance dept, handling the fume cupboard fans during repairs involved full body disposable coveralls, face shield, respirator, boots, gloves, etc, and calcium gluconate gel was always available just in case
In a previous career a long time ago, I worked in a lab while in college as a student chemist. My job was to prep metal alloys for analysis by the lead chemists. Some of the metal alloys are used in jet engines, the shuttle program, and nuclear industry and contain quite array of elements to produce the desired properties. Some of these alloys were high in silicon, and I had to use a mixture of HCL, HNO3, and HF in order to dissolve the alloy to perform analysis on an AA spectrograph. We used Teflon beakers because of the HF. I was always careful of HF because its a weak acid and you can't wash it off very easily if you get it on your skin, but the acid that all the chemists feared the most, and the one I treated very carefully was perchloric acid. It can go BOOM!
Used to work in a wafer fab clean room. HF was poured into big long baths (about 50 gallons) and we would carefully slide quartz glass tubes into the acid (they had handles on their sides) after a while they were removed having being cleaned because of etching effect. Once me and my workmate forgot about one and when we went back to the bath the tube had completely dissolved!! Very powerful stuff and not to be mishandled.
Why did the beaker have to be cloudy instead of clear?
+David Crawford The plastic used to contain it is produced in a different manner than other materials, even though they would have the same polymer formula. The thicker the folding, the more opaque and less pliable any given plastic will be.
Neurotransmission So you don't need to actually have a clouded one it is just a more durable plastic?
David Crawford The plastic is opaque because it is durable. If it was more transparent, there would be too many imperfections in the container; it wouldn't, well contain the hydrofluoric acid.
David Crawford Watch some educational videos about the production of plastics, and you'll understand why materials like the container used for HF here, and plastic wrap can be composed of the same polymer, but have different properties due to how the plastic is manufactured.
Neurotransmission I will, thanks for the information.
Wow, that just made breaking bad kinda boring.
in the show they don't mix it with water.
I can tell you now, I just breathed in hydrogen fluoride (by accident(byproduct of experiment)) and it hurts the lungs and bronchus
Did you die?
Deosn't matter, HF isn't strong enough to do what they showed in the show, no matter how concentrated.
You can't not mix it with water, pure HF is a gas. What we call hydrofluoric acid is a water solution of it.
simply amazing.
absolutely loved it
Wow. That was worth the wait. What an explosion! seriously though...love periodic videos.
I had no idea that there was a chemical out there that could dissolve glass.
Hey look, its my fave acid!
NaOH can dissolve glassO_o
Guess one of us wasn't watching breaking bad :D
***** I don't have TV.
Stephen Fonnesbeck you have internet
HF is probably the most feared chemical compound there is , how about dimethyl cadmium I ask
:D
Dimethylcadmium and Dimethylmercury are *both* nasty!
So is dimethyl zinc
+Nikola Genchev azidoazide azide
nitrogen trifluoride
Someone has been watching Hank Green :D
Nah, Dioxygen Diflouride
We need a proper episode about Neil soon. He puts his fingers/lungs/face/self on the line every time we get to see a video of a cool reaction. What's more, he's the one stuck cleaning up after all of them, and I feel that the chemistry of neutralizing/cleaning up after an awesome reaction is just as interesting as the reaction itself. I can imagine many other Periodic Videos viewers feel the same way. Love the vids Brady, thanks for doing what you do and please take this comment into consideration! after all, Neil is kinda your stig :P
Wow! Keep doing these cool experiments!
How does it cause a heart attack?
The fluorine ions (F-) are quite toxic, but I do not know why exactly. I only know that they can dissolve your bones, forming fluorite crystals (CaF2)
+derkateramabend Thanks
+DavidTheTech It reacts with calcium ions in your body, forming CaF2, which is insoluble and precipitates out of your blood. Calcium ions are essential to the contraction of muscles, including cardiac muscle.
+Yindog1 wow
Those fluorite crystals precipitate and act as cholesterol, blocking the arteries, possibly leading to pectoral anginas, aneurysms, strokes or heart attacks.
How many chemists do you need to change a lightbulb?
None, they'll just drop all the light bulbs in acid.
Definitively interesting!! Thanks professor!
Great video, and hip-hip-hooray for Neal!
Put more stuff in HF (i sound like a five year old, but i'm actually a nano-chemistry scientist). I'm really interested in its effect on different material. Or better so put stuff in PIRANHA (strongest acid there is, i won't disclose the ingredients because it is more dangerous that HF. Ppl who can use this information non-idioticaly already knows them.)
there are acids way stronger than piranha
Wait, isn't aqua regia the strongest? Or is it only special because it can dissolve gold and platinum?
I mean strongest acid that normal people can get (or in this case make). Yeah some organic acids are extremely difficult to even contain.
Aqua regia is very strong, but piranha is stronger.
Sulfiuric acid... hydrogen peroxide.... you get piranha. eager people are now satisfied
Algimantas Janarauskas How do you tell which acid is stronger/strongest?
Lol i remember when I went threw puberty 4:20
+Nick C THROUGH puberty. Ugh.
I absolutely love your videos.
I still like this video all these years later
why don't use some fluoroantimonic acid ?
اللي جاي من قضيه خاشقجي يضغط لايك
Nice video! I work at a HF alkylation unit. No room for errors. Every pipe in the acid part is made from Monel 400.
Fascinating, I love seeing this stuff. 👍
I was so naive that in 1974, I bought a gallon of HF so that I could etch stuff in glass. In my apt I poured some HF into a plastic dish tub and dipped a piece of window glass that I had coated in wax and drew a design on. I let it sit for a while - I do not remember anything about the project or the results. I do remember that the kitchen window in that apt was not as clear as it used to be. I knew enough to wear gloves, not to pour the stuff down the drain (I think that I took it out into the alley and dumped it there), and have no idea what happened to the rest of the acid. I remember that a couple years later some friends and I set up a bronze kiln/foundry in a shed in back of the 3D household on Aloha street. That is the last place I remember seeing it - I think that place was torn down in 1979. But a little knowledge is a dangerous thing (later I learned about Velvet Etching Cream - much safer).
I had taken part into an experiement where we dissolved beakerglass (broken pieces) in heated oleum (conc. sulfuric acid). The glass were "dissolved" only from the rough broken edges and the "flat surfaces" stayed mostly intact.
You professor are a nutter & I mean that in the most affectionate and complementry manner. Love your videos.
The professor's endless flailing with his hands is driving me nuts hehe. I still listen to all the interesting stuff he says but I have to scroll down when he's in frame. =P
Amusing experiment professor.
Watching these videos I don't even notice 5 minutes have passed.... I was going to play stellaris at 10pm and its now 12:32am and the launcher for the game is still sitting there lol
This is the beat channel on youtube
so if HF disolves glass and our stomaches are filled with a form of HF can people "eat" glass?
I work with borosilicate glass and this brings up so many questions
Finally a HF reaction video on youtube :D
wow, new glasses on Prof. Poliakoff!!! Pretty cool
Fascinating stuff.
What the experiment showed is that the corrosion of the glass is strongest right at the surface of the acid. Do the gasses in the air act like catalysts or does it have something to do with surface tension?
Thanks, I need this video.
Is it more reactive on the surface because of contact to the air? Does the oxygen help to corrode it faster? No chemist but it is very interesting watching your videos.
Have you tried putting. the broken shards of that lightbulb into the HCl and then experimenting from there
Many years ago I use to use Hydrofluoric Acid to etch on glass. Made wonderful art with it. You can purchase Hydrofluoric Acid in very diluted form for glass etching :)
Once found a lead bottle in an old house we were refurbishing. It had two concentric discoid protuberances at the neck. The top was unusual in that instead of a cork or lead stopper it had a small gilded perfume vial suspended by three or four tiny nails and embedded in the stopper. I could tell a liquid was inside. I was hesitant to try and open it. I left it in the back of an old Toyota pick up parked in front of my parents orchard while in college. I was unaware it had been ticketed for being immobile for too long and it was finally towed. I only paid $150 for it originally and didnt bother seeking it back. It was only later while perusing an old chemistry book I recognised the container for HF. I imagine the vial improvised into the stopper had a note inside warning of the danger of its contents. Then again, for all I know, the vial had nitroglycerin in it . . . iows, an improvised explosive device. I loath to think someone attempting to open it. More likely the kit and caboodle went into a compactor and recycled. Hope so.
What would concentrated HF do, or would the glass passivate like copper does in concentrated/fuming nitric acid in a manner that slows/stops the reaction, for example?
Just wondering the approximate final strength of HF(aq) in beaker (say, 1:1 by volume, or what?). Wondering what would happen if the feat is repeated in neat HF!
This stuff is awesome.
this makes perfect sense, heat and acid create fractal points in hard surfaces. it's how hannibal crossed the alps. with heating the rock and adding vinegar it created micro fissions all through the rocky terrain, he paved a path through the mountains cleverly.
I use to work on Watkins Johnson atmospheric glass deposition system for semi conductor manufacture. About every six months the glass would build up in the nitrogen injection muffle. We would install teflon covers and inject 50% HF into the N2 muffles and wait 2 hours to clean out the build up of glass. We always put on face shield, acid aprons, acid glove and had calcium glucomate nearby. It wasn't to scary when you take care and wear the proper PPE. I did hate that machine though.
You guys should definitely make a video about Aerogel!
Noticed the PFA beaker you poured that HF into. I have some myself. :)
@Periodic Videos The edge near the surface becomes hotter than the glass that's deeper in the liquid more heat is faster reaction hence the neat cut.
Isn't it rather the temperature differece between the submerged part of the bulb and the part that isn't cooled by the liquid that causes the bulb to break exactly at the point where it is touching the surface? I'm not sure about what kind of glass is used for simple light bulbs like this one, but I can only assume that, since these bulbs are made from some sort of glass that can handle temperature changes quite well, since this kind of bulb heats up quite a bit when the light is turned on. For the time the bulb was submerged, the HF didn't seem to have much effect on the glass, although it was apparently clouded a bit and therefore thinned, to some degree in the area where it was submerged. I've seen some cases where a slow change in temperature in glass can cause very clean breaking points, even if no acid whatsoever is involved. Would be interesting to check the temperatures of the liquid and the part of the bulb that is in air, or repeat the experiment just using water or some other heat absorbing liquid, I predict that the result would be about the same.
the bulb broke just like i hoped it would ... clean satisfying cut
What would happen if you put exposed wires in HF when whatever electronic you're using is plugged in and running? Would it just not work? Would it spark?