Edelsa Quejada Besides the obvious being respectful stuff: You never know when it hits you. So better appreciate every day and enjoy every small thing you learn regardless of your age. One must age and get old and sometimes I ask myself: How do I want to age? I knew an old man who was well into his 90s and he said to me, roughly translated: „I am really old, all people around me are younger and I don’t know what happens tomorrow. That’s fine. But do you know the one thing that really bothers me? I am just so curious about the world.“ I guess that was the secret of him living such a long live: There’s just too much to learn and wittness. :)
I remember in one video the Professor saying that some hours in the library saves you months of lab work. And now I watch that the issue with the Xe balloon was solved 100 years ago. That was a really nice proof of what he said before -- and poor Neil, he surely deserves a raise :D
This video is great for a multitude of reasons. 1. Leather pants. 2. Demonstrations. 3. Proves that anyone can learn something. 4. Challenges assumptions. 5. Easy to understand. 6. Affirms the value of the scientific method. I wish all TY content had this much value. Liked and Subbed.
Professor did you see that video by Cody's lab where oxygen leeched into the balloon when it was completely devoid of it to start with? This caused the balloon to grow in size.
serious? You mean like positive pressure (I guess the ambient heat of the atmosphere could have been used to make a pressurized reaction. Or did it just go up to STP.
@@IIGrayfoxII Are you sure it was only oxygen? Most likely the concentration of the diffused gasses in the balloon is most likely dependent on the permeability of the rubber by said gasses. I wonder if over a long period of time you'd find a similar composition of gasses inside of the balloon like in the atmosphere outside of the balloon, minus the SF6 of course.
Tell the Professor that if he fills the balloon with SF6, it will self-inflate rather than deflating. Check out the latest video from Cody's Lab for that :)
His Xenon balloon got all greasy though if I remember correctly, and he also attributed it to dissolution IIRC (although he might have said the Xenon reacted, I don't remember).
@@SgtLion I don't know about that, IIRC Cody's experiment had plenty of balloons, and they were initially all equally filled, so the stretching shouldn't be related?
@@ZoonCrypticon He presented a bunch of balloons with different gases at the beginning of that video if I'm not mistaken? Or that might have been a separate video on his B-Lab? Not sure.
Sir, not to take a shot at your age by no means. But for you to admit that at your age, and that you have learned something is a magical thing. A very smart man once told me, "the day you know everything about something, is the day you need to find a new something to learn.". Thank you for your knowledge, and sharing of said knowledge. Much love from Nebraska USA.
The professor is the Bob Ross of chemistry. I'm pulling my hair out with the stress of teaching math courses online. Every night I'm wound tight... Until I sit down and turn on periodic videos. The professors voice and demeanor melt the stress right out of me as he calmly delights in his passions for both teaching and chemistry. ...You know, it's even better than when I was young and my grandfather would read me a textbook before bed. 😊
Maybe that "stronger interaction" between the balloon and xenon resulted from van-der-waals interactions. Xenon Atoms are much larger than neon atoms and are as such more easily polarized which strengthens the van-der-waals interactions. (one might call xenon atoms more squishy/soft than neon) Maybe the HSAB-concept can explain it aswell. (I think the HSAB-consept would be a great topic for a future Periodic Video, it really isnt covered a lot on youtube.)
Another possible factor is that the heavy Xenon is slow enaugh to establish an interaction whereas the faster small atoms of Neon have too much kinetic energy and reflect off the surface before VdW-forces can take effect.
I don't think that HSAB is a valid explanation here. In this case, there is no electrostatic interaction, therefore no Lewis acid and base and therefore no room for HSAB as an explanation. I, too, would think that the highly diffuse structure of the Xenon atoms helps dissolving into the rubber. Xenon probably behaves a lot like methane or CF4 in that regard
@@Felixkeeg Now that i think about it using HSAB here really is quite the stretch. One could call the induced dipoles from the van-der-waals interaction electrostatic interaction, but that is way too flimsy to use it with HSAB. I agree with you
My favorite chemistry Professor! Always learning. And I totally agree: you're never too old to learn, something Sir Martyn Poliakoff demonstrates everyday.
Had some Helium balloons in the car one time, and when I braked, the balloons went backwards rather than forwards as we would normally expect. I figured the air in the car also moved forward and had a density profile with the senses air being at the front near the windscreen. It was odd watching the reverse of a normal expectation . Likey wouldn't work with the windows down.
It's not just air resistance in non-vacuum -- it's buoyancy. This is a very nice presentation, and I really appreciate the encouragement to keep reviewing past experiments and learning by doing experiments yourself.
Hello from Mexico, I love your videos, also your great job of converting this kind of experiments into videos for TH-cam, this is making the younger generations learn in a fun way. Thank you!
Monoatomic (Nobel) gases have a much smaller effective diameter than the "common" diatomic gases (O2, N2 and H2). Then you have chemical interactions within the elastomer (latex rubber, etc). O-ring manufactures (Parker O-ring) used to produce catalogs which had permeability tables for various gases and different seal compounds. PTFE (Teflon) and soft metals were the recommended seal materials for Helium (the most difficult "pure" element to seal.
Yeah, need to try mylar and also just plastic. My hypothesis would be that the mylar balloon would retain the Xe for the longest. I think plastic would work better than rubber but it would still leak via diffusion. I don't think Xe or other gasses dissolve into plastic?
This was an interesting experiment and demonstration. I have had a similar experience of large molecules dissolving while small molecules did not while using a specialized GCMS. The GCMS was portable. The MS portion worked with a "getter pump" rather than a vacuum pump. To keep the system free of carrier gas, a silicone septa separated the carrier gas from the MS at the outlet of the GC column. The organic compounds that we were looking for readily dissolved in the silicone and then on to the MS while the carrier-gas was vented. It was an incredibly clever system that worked exceptionally well. This demonstration really drove the point home. Thank you.
Perhaps the key point is the polarisability of the gas? The more polarisible, the stronger the electrostatic interactions with the rubber surface and the gas molecule leading to better diffusion through the rubber. In the paper Martyn mentions (1920) Edwards & Pickering, they give the permeability of gases through rubber as: Nitrogen < Argon < Oxygen < Helium < Hydrogen. Here, you find that Nitrogen < Neon < Krypton < Xenon. Surely, these are arranged by polarisability??
It would light up a little, but to get the discharge visible at the atmospheric pressure your discharge current would need to be in the tens of amperes per square millimeter of gas, which is really high. This however is done with Xenon and Argon in short discharge lamps, where the gas pressure in in the hundreds of bar range in operation, and the current through the arc is in the order of 5-50A depending on size, and you get a lot of white light, plus an incredible amount of heat as well at the anode, which is in most larger units water cooled, as it has to dissipate kilowatts of power. They also need shielding all round, as they are also quite strong X-ray emitters, though at the levels they emit all you need is 2mm of aluminium sheet anyway, which acts as a light shield as well, because the gas discharge is brighter than the sun. They also have a limited life, and if you run them too far past this they tend to explode spectacularly as the internal pressure rises too high for the thick quartz glass to contain. The bigger ones are also rebuildable, so you do not throw them out, you send them back to be rebuilt, as there is a big core charge paid on them. Most common place to find them is in a cinema, providing the light source for the projector, whether the image comes from 35mm film, 70mm Imax film or from a DLP array.
@@mernokimuvek They do generate them, though admittedly in small amounts, and most are absorbed and scattered down to nothing before leaving the plasma around the anode.
Very interesting. I have a question though: Does the dissolved Xe escape the balloon, or it just accumulates in the rubber of the balloon wall until it reaches some saturation point? Because my instinct would tell me that, since diffusion rate is very low for Xe and the dominant and energetically favourable process is dissolving, the balloon would loose some volume (until the saturation concentration of Xe in the rubber is reached) and then maintain the rest of the gas for a longer period. So has the balloon stopped shrinking after some point? Also, has the weight of the balloon changed significantly after its shrinking? Because, if the Xe indeed accumulated in the rubber wall, I believe it shouldn't have...
I just love to way the professor starts every video. It keeps reminding me of my school lab. Thumbs up to the professor for presenting us with amazing content. Stay safe professor.
One should note that carbon dioxide ("complex" molecule), hydrogen (diatomic molecule) and the noble gasses (near-ideal monatomic gases) have quite different mean kinetic energy at any given temperature. This is because of the equipartition theorem and the fact that the two former have more degrees of freedom. Diatomic molecules already have rotational and vibrational energy in addition to kinetic energy of monatomic gas atoms. So the mean velocity of particles does not depend solely on their mass because these additional degrees of freedom reduce kinetic energy.
It is nice to see Sam again and I'm glad she's apparently doing well at Nottingham! Are most of the folks who've been in your PToV videos still there in the department?
2:33 Just keeping the facts streight: no, the baloon with heavier gas falls to the ground faster not because of air resistance, but because of Archimede's force. If baloon is filled with gas heavier than air, it will float due to positive Archimede's force, the heavier the gas the faster it falls because of same force. If balloons were in vacuum, they would fall down at same speed, because they would not be able to float in vacuum.
Indeed, air resistance mostly affects terminal velocity, and is obviously 0 at the start of the fall. On the slowmo we would see the balloons start falling identically at the start, that is very clearly not the case.
Its both. The 'weight' is not mass. If two objects have the same weight but different cross section then air resistance changes things. Also in this definition of weight a helium ballon has negative weight.
The reason that xenon dissolves better in rubber than neon is simply that an atom of xenon has more electrons (54) that an atom of neon (10). Rubber is a hydrocarbon with a very small dipole moment; we say that is (mostly) nonpolar. Monoatomic molecules are always nonpolar. Therefore, the intermolecular forces between the rubber and noble gas cannot be hydrogen bonding or dipole-dipole. This leaves the so-called London (also called "dispersion") force. The strength of this force depends (mostly) on the number of electrons in each (and slightly on the shape). Since xenon has many more electrons than neon, it will have a stronger London force between it and rubber than neon does (between neon and rubber). This means that xenon dissolves in rubber more easily than does neon.
I love the professor he makes learning fun I think it’s his excitement about whatever he’s talking about in the video plus his hair how can you not love the hair
Myself, and I'm sure many others, really appreciate these video documenting fascinating chemistry phenomena and behaviour. It allows people like us access to knowledge that would otherwise be nigh impossible to experiment with on our own.
Great video! Btw, @2:30, I think (although I may be wrong) that even more significant than the air resistance is the difference in the densities of the various gasses, and thus in the corresponding buoyancy force on each balloon as it is immersed in the atmospheric air.
8:07 is probably the most important takeaway from this video. Even though it's Nov of 2020 there's TONS of knowledge from the past needing to be rediscovered. Great video. Thank you!
I saw the effects of xenon in rubber when working in a radiochemistry lab, and xenon-133 really absorbed into surgical tubing, and required a lot of purging with air to get the radioxenon back to undetectable levels. I even experienced this with radioxenon adsorbing in stainless steel and PTFE tubing. Noble gases are cool (and instructive)!
Imagine having a party where all the balloons are full of something heavy like Xenon and freak everyone out with how they drop like they're rocks but still have a gas inside.
i like that obvious questions get asked both for the purpose of teaching and because it can also be insightful to be reminded of something you may well have forgotten having learned it years ago
I see your point, but it's not quite that way. It would be tautological if he said: It dissolves more because it has a higher rate of dissolution. Instead, it's said that it dissolves more, which is a _macroscopical observation_, because the atoms interact. He alludes to a microscopic explanation. Of course, you still have a point in that the nature of this microscopic interaction is not explained. I would guess that Xenon is easier to polarize, so the nature of the interaction should be Van-der-Waals Forces, but I have no way of knowing.
Fascinating. By the way, 2:34 he mentions air resistance, but really the most important factor is buoyancy, which depends on the relative densities of the inside and the outside.
The argon cylinders are never in danger of needing disposal in a chemistry lab, argon is used so much in chemistry that the cylinders empty and are sent to be refilled on a regular basis. Some universities dont even use argon cylinders, but have a large tank of liquid argon, and get regular liquid argon deliveries. (ICP-OES machines are notorious for using very large amounts of argon and beyond a certain point it is cheaper to buy liquid argon)
@@TheBackyardChemist where i worked for many years had a huge tank of what i believed was argon and a smaller but still large one of oxygen? Im not very educated on this but it was used for a huge laser cutter used to cut sheets of steel from the plans that the guys in the offices drawn. When the truck would fill the tanks huge clouds of steam or something with pillow everywhere. Again im not 100% sure of the gases uses. I know the welders used argon cylinders and other stuff for something. I was a painter there for many years and didn't worry too much about other departments. Although i was curious about it all.
@@the_original_Bilb_Ono The gas being delivered was likely to have been either liquid nitrogen or liquid argon. The clouds were actually fog, when liquid gases like that evaporate, the gas is still very cold and instantly freezes out the humidity from the air. Hence the fog/clouds.
Fascinating. I must revise my understanding of the word 'dissolve'. If I put sugar in my tea, it dissolves. I have always taken that to imply a degree of 'breaking down'. Molecules of sugar break out of a crystal lattice and go swimming about in the tea. I assumed that single atom molecules like Xenon could not 'break down' into smaller units, so could not dissolve. They can be absorbed - no problem. So what is happening in the rubber is not just gas molecules knocking through gaps between rubber molecules - they are interacting with the rubber? Temporary bonds formed and broken? Just thought of an expression - "he dissolved into the crowd". I am sure I have heard that used...
The tires in my Prius came filled with N². I let it out and filled them with Argon. Thinking that Argon was a larger molecule and would make the tires last longer. But, I spent the next 8 years adding more Argon every 3 or 4 weeks. I got 80k miles on the tires. The tires did "sound" different. With N² they sounded like basketballs, ringing on every bump. Filled with Ar they were noticeably more quiet. BTW owing your own tanks, driving them down to the industrial gasses place and paying for refills is WAY cheaper. I just have to have them hydro tested ($5 usd) every 5 years or so.
The solubility is also linked to the anesthetic properties of xenon. An old rule of thumb links the strength of anesthetics to their solubility in olive oil, and N2O is used to pressurize whipped cream because it dissolves well in the lipids of cream.
Xe has a property that CO2 also has, which is polarizability. The clouds of electrons in the Xe are very large, and the electron density is able to be moved and polarized, there is a higher chance for there to be more electrons on one side of the molecule, creating a dipole. This dipole moment can interact with dipoles in the rubber itself (or induced dipoles either by chance like Xe or another dipole from the Xe itself). This electrostatic interaction creates an attractive force which then allows the molecules of Xe to get closer and get trapped in the rubber and then diffuse out afterwards. Interesting science!
I read an article about different gases being used in windows for insulation. Xenon was actually not that great because it was "slippery" they said. It had to have a much thinner gap between pains of glass because it created convection currents more easily. Wonder if the Xenon "slipped" between the rubber molecules more easily?
Well, the density of the gas is almost directly proportional to the atomic/molecular weight. For ideal gases, the molar volume is equal for all those gases at a certain temperature. So, helium (4 g/mol) and neon (20 g/mol) are lighter than nitrogen (28 g/mol), argon (40 g/mol), krypton (84 g/mol) and xenon (131 g/mol) are heavier. In case of the xenon, it's more than four times as heavy as nitrogen.
Never stop learning; never stop teaching, Professor.
I think the value of this experiment was somewhat inflated. ;-)
I always said: Learn something new every day (and/or variants of the phase.)
I agree with you Edelsa. He’s going to die one day. Much like your grammar the moment you started typing.
@@edelsaquejada4401 wouldn't it be ironic if you got flattened by COVID-19 while the professor goes on for many more decades?
Edelsa Quejada
Besides the obvious being respectful stuff:
You never know when it hits you. So better appreciate every day and enjoy every small thing you learn regardless of your age. One must age and get old and sometimes I ask myself: How do I want to age?
I knew an old man who was well into his 90s and he said to me, roughly translated: „I am really old, all people around me are younger and I don’t know what happens tomorrow. That’s fine. But do you know the one thing that really bothers me? I am just so curious about the world.“
I guess that was the secret of him living such a long live: There’s just too much to learn and wittness. :)
Ah yes the 4 famous noble gases:
Neon
Xenon
Krypton
Martyn
Martyon
I thought 'noble' gas would not want to react or even diffuse into 'common' substances.
helium
I appreciate your profile picture
Neil
I remember in one video the Professor saying that some hours in the library saves you months of lab work. And now I watch that the issue with the Xe balloon was solved 100 years ago. That was a really nice proof of what he said before -- and poor Neil, he surely deserves a raise :D
Português?
He’ll only spend it on leather.
Programmers say this too...
10 minutes of reading the instructions could save you hours of debugging the errors in your code xD
2 minutes on google .....
This video is great for a multitude of reasons.
1. Leather pants.
2. Demonstrations.
3. Proves that anyone can learn something.
4. Challenges assumptions.
5. Easy to understand.
6. Affirms the value of the scientific method.
I wish all TY content had this much value. Liked and Subbed.
"... So, I persuaded Neil..."
We know that, after these words, something interesting ALWAYS come. Keep hungry, Professor!
i was looking for this comment haha
"persuaded Neil"
"Keep hungry"
You make it sound like he seduced him.
Professor did you see that video by Cody's lab where oxygen leeched into the balloon when it was completely devoid of it to start with?
This caused the balloon to grow in size.
Coincidence? I think not.
It is bit more complex, he also tried with Argon and it did not inflate.
serious? You mean like positive pressure (I guess the ambient heat of the atmosphere could have been used to make a pressurized reaction. Or did it just go up to STP.
@@vangildermichael1767 Cody inflated a balloon with Sulfur hexafluoride and the balloon grew in size as it absorbed the O2 from the air.
@@IIGrayfoxII Are you sure it was only oxygen? Most likely the concentration of the diffused gasses in the balloon is most likely dependent on the permeability of the rubber by said gasses. I wonder if over a long period of time you'd find a similar composition of gasses inside of the balloon like in the atmosphere outside of the balloon, minus the SF6 of course.
Xenon walked into a bar.
The barman said "We don't serve your type in here."
Xenon didn't react.
@Cole Clapperton touché
? What Did One Eye Say To The Other Eye ,
" Between You And Me Something Smells . "
Cole Clapperton well, all noblemen have their secrets ;)
I can't believe no one has pointed out the barman is *xenophobic*.
@@NoxUmbrae I was leaving it there for you to point it out. 😀
Tell the Professor that if he fills the balloon with SF6, it will self-inflate rather than deflating. Check out the latest video from Cody's Lab for that :)
Always nice to see the edu community watches the same stuff I do;)
I instantly thought of Cody when I saw this video as well. Glad I'm not the only one.
Ich Auch
That nitrogen balloon seemed to do the same. I don’t know if it just looked bigger than before or it was bigger.
Top 10 Science cross-overs we want to see
1:20 ah yes, my favorite noble gas, Martyn.
The most important attribute that a scientist can have is “i realised my hypothesis was wrong.”
“Hmm, that’s odd....”
That happens a lot
Cody did a similar experiment but his showcases the osmosis process.
His Xenon balloon got all greasy though if I remember correctly, and he also attributed it to dissolution IIRC (although he might have said the Xenon reacted, I don't remember).
@@cheaterman49 It got greasy most likely because of the plastic decomposition. It decomposed much faster due to it being more thinly stretched.
@@SgtLion I don't know about that, IIRC Cody's experiment had plenty of balloons, and they were initially all equally filled, so the stretching shouldn't be related?
@@cheaterman49 It was SF6 if you are relating to his video "Self Inflating Balloons?!"
@@ZoonCrypticon He presented a bunch of balloons with different gases at the beginning of that video if I'm not mistaken? Or that might have been a separate video on his B-Lab? Not sure.
Sir, not to take a shot at your age by no means. But for you to admit that at your age, and that you have learned something is a magical thing. A very smart man once told me, "the day you know everything about something, is the day you need to find a new something to learn.". Thank you for your knowledge, and sharing of said knowledge. Much love from Nebraska USA.
Doctor is getting so old, I wish that I was as active when I become old. Keep educating, love from the world!
The professor is the Bob Ross of chemistry. I'm pulling my hair out with the stress of teaching math courses online. Every night I'm wound tight... Until I sit down and turn on periodic videos. The professors voice and demeanor melt the stress right out of me as he calmly delights in his passions for both teaching and chemistry.
...You know, it's even better than when I was young and my grandfather would read me a textbook before bed. 😊
Maybe that "stronger interaction" between the balloon and xenon resulted from van-der-waals interactions. Xenon Atoms are much larger than neon atoms and are as such more easily polarized which strengthens the van-der-waals interactions. (one might call xenon atoms more squishy/soft than neon)
Maybe the HSAB-concept can explain it aswell.
(I think the HSAB-consept would be a great topic for a future Periodic Video, it really isnt covered a lot on youtube.)
That is what I also thought and was expecting professor to say.
That was my guess too.
Another possible factor is that the heavy Xenon is slow enaugh to establish an interaction whereas the faster small atoms of Neon have too much kinetic energy and reflect off the surface before VdW-forces can take effect.
I don't think that HSAB is a valid explanation here. In this case, there is no electrostatic interaction, therefore no Lewis acid and base and therefore no room for HSAB as an explanation.
I, too, would think that the highly diffuse structure of the Xenon atoms helps dissolving into the rubber. Xenon probably behaves a lot like methane or CF4 in that regard
@@Felixkeeg Now that i think about it using HSAB here really is quite the stretch. One could call the induced dipoles from the van-der-waals interaction electrostatic interaction, but that is way too flimsy to use it with HSAB. I agree with you
Professor I just found you today and I must say you are awesome. I have always loved my teachers and you make the complex understandable. Thank You
Im glad to see that the professor is alright and well during these chaotic and worrying times. thanks for keeping the videos up!
My favorite chemistry Professor! Always learning. And I totally agree: you're never too old to learn, something Sir Martyn Poliakoff demonstrates everyday.
Cody's Lab did a similar experiment recently with a surprising result.
Had some Helium balloons in the car one time, and when I braked, the balloons went backwards rather than forwards as we would normally expect. I figured the air in the car also moved forward and had a density profile with the senses air being at the front near the windscreen. It was odd watching the reverse of a normal expectation . Likey wouldn't work with the windows down.
1:23 one balloon was filled with Martyn.
The Martyn Noble Gas
It's not just air resistance in non-vacuum -- it's buoyancy. This is a very nice presentation, and I really appreciate the encouragement to keep reviewing past experiments and learning by doing experiments yourself.
The proff really needs to see cody's videon on the subject
Hello from Mexico, I love your videos, also your great job of converting this kind of experiments into videos for TH-cam, this is making the younger generations learn in a fun way.
Thank you!
1:20 missed excellent opportunity to label bottom right square "Martyon" :)
Monoatomic (Nobel) gases have a much smaller effective diameter than the "common" diatomic gases (O2, N2 and H2). Then you have chemical interactions within the elastomer (latex rubber, etc). O-ring manufactures (Parker O-ring) used to produce catalogs which had permeability tables for various gases and different seal compounds.
PTFE (Teflon) and soft metals were the recommended seal materials for Helium (the most difficult "pure" element to seal.
I wonder how the Xe would behave in a (metalized) mylar balloon, which has a layer of Al sandwiched therein?
🎈You want a balloon? THEY ALL...well, actually, some of them float, and some of them sink at different rates...DOWN HERE! BWAHAHAHAHA!
Yeah, need to try mylar and also just plastic. My hypothesis would be that the mylar balloon would retain the Xe for the longest. I think plastic would work better than rubber but it would still leak via diffusion. I don't think Xe or other gasses dissolve into plastic?
This was an interesting experiment and demonstration. I have had a similar experience of large molecules dissolving while small molecules did not while using a specialized GCMS. The GCMS was portable. The MS portion worked with a "getter pump" rather than a vacuum pump. To keep the system free of carrier gas, a silicone septa separated the carrier gas from the MS at the outlet of the GC column. The organic compounds that we were looking for readily dissolved in the silicone and then on to the MS while the carrier-gas was vented. It was an incredibly clever system that worked exceptionally well. This demonstration really drove the point home. Thank you.
You know that guy who knows a guy that gets the thing done? Neil is the guy that gets it done.
Videos like this are a reason for youtube to provide a heart reaction.
Thanks for another great video! Always interesting.
Perhaps the key point is the polarisability of the gas? The more polarisible, the stronger the electrostatic interactions with the rubber surface and the gas molecule leading to better diffusion through the rubber.
In the paper Martyn mentions (1920) Edwards & Pickering, they give the permeability of gases through rubber as: Nitrogen < Argon < Oxygen < Helium < Hydrogen. Here, you find that Nitrogen < Neon < Krypton < Xenon. Surely, these are arranged by polarisability??
Does static electricity jumping from balloon to balloon lighting up the xenon or neon gas ? That'd be cool
It would light up a little, but to get the discharge visible at the atmospheric pressure your discharge current would need to be in the tens of amperes per square millimeter of gas, which is really high. This however is done with Xenon and Argon in short discharge lamps, where the gas pressure in in the hundreds of bar range in operation, and the current through the arc is in the order of 5-50A depending on size, and you get a lot of white light, plus an incredible amount of heat as well at the anode, which is in most larger units water cooled, as it has to dissipate kilowatts of power. They also need shielding all round, as they are also quite strong X-ray emitters, though at the levels they emit all you need is 2mm of aluminium sheet anyway, which acts as a light shield as well, because the gas discharge is brighter than the sun.
They also have a limited life, and if you run them too far past this they tend to explode spectacularly as the internal pressure rises too high for the thick quartz glass to contain. The bigger ones are also rebuildable, so you do not throw them out, you send them back to be rebuilt, as there is a big core charge paid on them. Most common place to find them is in a cinema, providing the light source for the projector, whether the image comes from 35mm film, 70mm Imax film or from a DLP array.
@@SeanBZA High pressure lamps are UV emitters, not X-ray emitters. You need a very low pressure for X-rays.
@@mernokimuvek They do generate them, though admittedly in small amounts, and most are absorbed and scattered down to nothing before leaving the plasma around the anode.
@@SeanBZA You also need more than 20 kV to generate hard X-rays which can pass through the glass. Several hobbyists tried this with vacuum tubes.
YOU ARE JUST AWESOME SIR.
I have no words for you
YOU ARE AWESOME👏🏻👏🏻
I would love to have a teacher like you, dear sir😊
You should do something on the self-filling balloons of sulfur hexafloride. Instead of leaking out they expand.
Agree!!!
Possibly try a Mylar balloon?
Keep them coming Sir. your awesome- Thanks
Very interesting. I have a question though: Does the dissolved Xe escape the balloon, or it just accumulates in the rubber of the balloon wall until it reaches some saturation point? Because my instinct would tell me that, since diffusion rate is very low for Xe and the dominant and energetically favourable process is dissolving, the balloon would loose some volume (until the saturation concentration of Xe in the rubber is reached) and then maintain the rest of the gas for a longer period. So has the balloon stopped shrinking after some point? Also, has the weight of the balloon changed significantly after its shrinking? Because, if the Xe indeed accumulated in the rubber wall, I believe it shouldn't have...
6:20
There is a dynamic equilibrium between all phases and the vapor pressure of Xe is very high. Xe escapes easily into the atmosphere.
I just love to way the professor starts every video. It keeps reminding me of my school lab. Thumbs up to the professor for presenting us with amazing content. Stay safe professor.
4:13 "... and I could show it to visitors and say WOW look a balloon of Xenon!" I love it
One should note that carbon dioxide ("complex" molecule), hydrogen (diatomic molecule) and the noble gasses (near-ideal monatomic gases) have quite different mean kinetic energy at any given temperature. This is because of the equipartition theorem and the fact that the two former have more degrees of freedom. Diatomic molecules already have rotational and vibrational energy in addition to kinetic energy of monatomic gas atoms. So the mean velocity of particles does not depend solely on their mass because these additional degrees of freedom reduce kinetic energy.
It is nice to see Sam again and I'm glad she's apparently doing well at Nottingham! Are most of the folks who've been in your PToV videos still there in the department?
Agreed. I like Sam and it would be nice to have a new Sam episode of periodic videos!
2:33 Just keeping the facts streight: no, the baloon with heavier gas falls to the ground faster not because of air resistance, but because of Archimede's force. If baloon is filled with gas heavier than air, it will float due to positive Archimede's force, the heavier the gas the faster it falls because of same force. If balloons were in vacuum, they would fall down at same speed, because they would not be able to float in vacuum.
Indeed, air resistance mostly affects terminal velocity, and is obviously 0 at the start of the fall. On the slowmo we would see the balloons start falling identically at the start, that is very clearly not the case.
Its both. The 'weight' is not mass. If two objects have the same weight but different cross section then air resistance changes things.
Also in this definition of weight a helium ballon has negative weight.
*inhales xenon*
*IN A WORLD...*
I laughed too much at this lol
**suffocates**
You would actually get high from doing so :^)
@@Zumash it would have a similar effect to nitrous oxide if I'm remembering correctly
@@blindsniper35 did you try inhaling Xenon?
The reason that xenon dissolves better in rubber than neon is simply that an atom of xenon has more electrons (54) that an atom of neon (10). Rubber is a hydrocarbon with a very small dipole moment; we say that is (mostly) nonpolar. Monoatomic molecules are always nonpolar.
Therefore, the intermolecular forces between the rubber and noble gas cannot be hydrogen bonding or dipole-dipole. This leaves the so-called London (also called "dispersion") force. The strength of this force depends (mostly) on the number of electrons in each (and slightly on the shape).
Since xenon has many more electrons than neon, it will have a stronger London force between it and rubber than neon does (between neon and rubber). This means that xenon dissolves in rubber more easily than does neon.
Anyone else completely not surprised that Neil is wearing what appear to be leather pants to work?
Hes 100% got a bdsm group meet every Saturday in some discrete location. Lol jk but no judgment if he did.
Is it possible that he is a biker ?
@@gerhardhermann1571 I remember it being said in one of the videos that he rides a motorcycle, but I can't begin to tell you which one it was.
@@FurrBeard Thank you for the info.
Neil's pants makes me think Neil "persuaded " the professor to do a experiment
I love the professor he makes learning fun I think it’s his excitement about whatever he’s talking about in the video plus his hair how can you not love the hair
1:14 I’ve always thought Martyn was a gas, but I didn’t realize he was noble!
Myself, and I'm sure many others, really appreciate these video documenting fascinating chemistry phenomena and behaviour. It allows people like us access to knowledge that would otherwise be nigh impossible to experiment with on our own.
1:21 Noble gases: Xenon, Neon, Krytpon, Martyn.
His Highness
I already did that joke.
I did a page refresh and now I see comments that were several minutes before mine. TH-cam is strange the way it displays comments.
@@sbalogh53 i don't care, at least you noticeed it.
That was some genius editing.
Great video! Btw, @2:30, I think (although I may be wrong) that even more significant than the air resistance is the difference in the densities of the various gasses, and thus in the corresponding buoyancy force on each balloon as it is immersed in the atmospheric air.
"One is never too young, or too old, to learn things."
pretty sure an one month baby isn't ready for quantum physics
This video is so beautiful. Just pure and science.
I love how you had to put ‘Martyn’ on the 2x2 frames just to make sure we know he isn’t a balloon 😂😂
8:07 is probably the most important takeaway from this video. Even though it's Nov of 2020 there's TONS of knowledge from the past needing to be rediscovered. Great video. Thank you!
1:42 now that's some serious hurry
Love your lectures! Please never stop teaching!!!
He should try putting sulfur hexaflouride in a balloon, CodysLab showed that the balloon gets bigger instead of smaller....crazy!
The professor is a character. Love you guys and your videos.
4:37 Professor's persuasion skills comes into play again.
I saw the effects of xenon in rubber when working in a radiochemistry lab, and xenon-133 really absorbed into surgical tubing, and required a lot of purging with air to get the radioxenon back to undetectable levels. I even experienced this with radioxenon adsorbing in stainless steel and PTFE tubing. Noble gases are cool (and instructive)!
Imagine having a party where all the balloons are full of something heavy like Xenon and freak everyone out with how they drop like they're rocks but still have a gas inside.
Freak everyone out? Is this a party for 5 year olds? Lol
I think you can just think of it as a water balloon, except for the sloshing around thing, so not so exciting.
Even if you fill normal air in balloons, they are gonna fall, because the air is 78% nitrogen, 21% oxygen and 1% other air 😊
Very interesting! I’ve always found gases very challenging in chemistry and it’s neat that even a professor can be surprised by it
Codyslab done a very similar experiment on his channel with gases and balloons
Yes. We know. The 50 other comments already told us
@@michaelesposito2629 there wasnt 50 other comments when I said it though was there ...
Mortiis-Aaron you sure about that?
the real learned guys in the world, such as the Professor relish surprises for the chance to know more. great vid
"There was another reason i wanted the balloons filled"
Thought he was going to say after ... "cuz i wanted to have a party" xD
i like that obvious questions get asked both for the purpose of teaching and because it can also be insightful to be reminded of something you may well have forgotten having learned it years ago
1:17 Xenon, Neon, Krypton, Martyn
Martyn being the noblest and rarest of all elements ;-)
I love seeing experiments I'll never be able to perform. Thanks, guys. Cheers, and stay safe!
Codyslab had a video on this lately
Yes. We know. The 50 other comments already informed us
So well said professor. I taught at university myself and it is true, you never stop learning.
I like Neil's trousers and boots, does he ride a motorcycle?
He rides on the theoretical physics motorcycle, the METAcycle!
@@flappy7373 He runs the Carnot cycle.
@@gabor6259 HA HA HA
They did mentioned that he owns a motorcycle, it's in a video about lithium battery iirc.
Imagine wearing leathers and protective boots but turning up on a push hine
I LOVE this guy! I watch him for more then 10 years now. He is still as funny as back then!
"It dissolves more because it interacts more"
Ah yes, the floor is indeed floor
I see your point, but it's not quite that way.
It would be tautological if he said: It dissolves more because it has a higher rate of dissolution.
Instead, it's said that it dissolves more, which is a _macroscopical observation_, because the atoms interact.
He alludes to a microscopic explanation.
Of course, you still have a point in that the nature of this microscopic interaction is not explained.
I would guess that Xenon is easier to polarize, so the nature of the interaction should be Van-der-Waals Forces, but I have no way of knowing.
Fascinating. By the way, 2:34 he mentions air resistance, but really the most important factor is buoyancy, which depends on the relative densities of the inside and the outside.
It just occurred to me that Neil probably rides a motorcycle and is probably not a member of a goth rock band.
Why not both?
I was wondering if I was the only one impressed by those pants rofl
@@kulganspipe They did seem a bold choice for a science video, but the motorcycle theory seems likely.
Professor Poliakoff always makes my day better!
cyclists are well aware of co2 and rubber
@@ILostYourSoul Aren't you a little young to do that?
@@nadaso8819 there are pocket size tire inflators (for road bikes I think) using co2 to fill it up quickly but not lasting very long...
@@ILostYourSoul People who switch 0 and O were usually taught to type on a typewriter. :)
After 22 years in education, I agree that you should always be learning new things. Thank you, Sir Martin!
So, anyone else annoyed at the lack of Argon? A pity this one wasn't included... I guess no Argon was in need of being disposed of. Oh well...
The argon cylinders are never in danger of needing disposal in a chemistry lab, argon is used so much in chemistry that the cylinders empty and are sent to be refilled on a regular basis. Some universities dont even use argon cylinders, but have a large tank of liquid argon, and get regular liquid argon deliveries. (ICP-OES machines are notorious for using very large amounts of argon and beyond a certain point it is cheaper to buy liquid argon)
@@TheBackyardChemist where i worked for many years had a huge tank of what i believed was argon and a smaller but still large one of oxygen? Im not very educated on this but it was used for a huge laser cutter used to cut sheets of steel from the plans that the guys in the offices drawn. When the truck would fill the tanks huge clouds of steam or something with pillow everywhere. Again im not 100% sure of the gases uses. I know the welders used argon cylinders and other stuff for something. I was a painter there for many years and didn't worry too much about other departments. Although i was curious about it all.
@@the_original_Bilb_Ono The gas being delivered was likely to have been either liquid nitrogen or liquid argon. The clouds were actually fog, when liquid gases like that evaporate, the gas is still very cold and instantly freezes out the humidity from the air. Hence the fog/clouds.
I love this old man lol I come to watch the videos just to brighten my mood.
I'm a simple person. I see the professor, I click.
Ditto
Fascinating. I must revise my understanding of the word 'dissolve'. If I put sugar in my tea, it dissolves. I have always taken that to imply a degree of 'breaking down'. Molecules of sugar break out of a crystal lattice and go swimming about in the tea. I assumed that single atom molecules like Xenon could not 'break down' into smaller units, so could not dissolve. They can be absorbed - no problem. So what is happening in the rubber is not just gas molecules knocking through gaps between rubber molecules - they are interacting with the rubber? Temporary bonds formed and broken? Just thought of an expression - "he dissolved into the crowd". I am sure I have heard that used...
1:14 Some are Old Farts, some are Noble Gases. The Professor is a Noble Gas.
The tires in my Prius came filled with N². I let it out and filled them with Argon. Thinking that Argon was a larger molecule and would make the tires last longer. But, I spent the next 8 years adding more Argon every 3 or 4 weeks. I got 80k miles on the tires. The tires did "sound" different. With N² they sounded like basketballs, ringing on every bump. Filled with Ar they were noticeably more quiet. BTW owing your own tanks, driving them down to the industrial gasses place and paying for refills is WAY cheaper. I just have to have them hydro tested ($5 usd) every 5 years or so.
I love how Neil is always just wearing black leather pants and almost never talks
The solubility is also linked to the anesthetic properties of xenon. An old rule of thumb links the strength of anesthetics to their solubility in olive oil, and N2O is used to pressurize whipped cream because it dissolves well in the lipids of cream.
WHOA, Xenon the Mysterious Element!!!
Xenon gets even weirder. It interfaces with NMDA receptors and AMPA receptors. Meaning it can be used like nitrous oxide is in medical applications.
Humility is a rare virtue seen especially among scientists. I respect you even more now! Lead the way!
The largest book in the office of a world-reknowned chemist? "Russian".
Dr. Poliakoff has Russian ancestors.
Xe has a property that CO2 also has, which is polarizability. The clouds of electrons in the Xe are very large, and the electron density is able to be moved and polarized, there is a higher chance for there to be more electrons on one side of the molecule, creating a dipole. This dipole moment can interact with dipoles in the rubber itself (or induced dipoles either by chance like Xe or another dipole from the Xe itself). This electrostatic interaction creates an attractive force which then allows the molecules of Xe to get closer and get trapped in the rubber and then diffuse out afterwards. Interesting science!
Reaffirming a 100 year old “proof”
These videos are a global treasure.
Another great video! Thank you, Professor, for your demonstration!
Even though I finished my chemistry class I still love to see more of your videos
I just love that periodic table tie! And that quintessentially crowded office!
So much science in such simple experiment.amazing
I read an article about different gases being used in windows for insulation. Xenon was actually not that great because it was "slippery" they said. It had to have a much thinner gap between pains of glass because it created convection currents more easily. Wonder if the Xenon "slipped" between the rubber molecules more easily?
Thank You Professor Sir Martyn Poliakoff .
Well, the density of the gas is almost directly proportional to the atomic/molecular weight. For ideal gases, the molar volume is equal for all those gases at a certain temperature. So, helium (4 g/mol) and neon (20 g/mol) are lighter than nitrogen (28 g/mol), argon (40 g/mol), krypton (84 g/mol) and xenon (131 g/mol) are heavier. In case of the xenon, it's more than four times as heavy as nitrogen.
So balloons or this kind of membranes could be used for separating gases ?