Hello Ben, I can not believe it. My channel is booming !!! Thank you very much ... The MOT Magnet is a great idea! Many thanks also to the many new subscribers of my channel - I am thrilled!!! :-)
The only reason you don't have a couple of million subscribers is because your topics are too complicated for the mainstream. But those who understand your topics (your videos) appreciate every single one. Thanks a lot for all your work.
Very nice!. You take a lab curiosity and make it an undeniable, macroscopic demonstration. I will be very interested in your video on magnetic materials. We are building a large, permanent magnetic yoke to demonstrate magneto-hydrodynamic principles and applications. The magnets are easy, the steel and engineering are not. Cheers.
Can't wait for the next video Ben, and glad you gave Funk's channel a shout-out, they've had consistently awesome practical physics demonstrations for ages, highly recommended
Btw. Here's a tip on getting. Microwave oven transformers. If you go to one of the electronic recycling days ( usually in supermarket parking lots on a specified weekend) the items that are usually dropped off are printers, monitors, and Microwaves. Almost all microwave ovens stop working b/c the magnatron burns out. Meaning the transformer is more than likely good. Slip the guy $10 or $20 and ask the guy for a couple transformers. Bring the necessary tools, dont make a mess, try to be inconspicuous, and try to reassemble it after you take it out. I asked the guy what they do with all that stuff. He said they all go in a big shredder, so it doesnt matter whats left in them. I managed to get 4 MOTs for $10. I could have got more, but I didnt wanna get him in trouble with his boss. A friendly reminder. The capacitors in microwave ovens can be hazardous even when not plugged in. Make sure the first thing you do when you get it opened is arc the cap with a screwdriver with one hand and other hand in your pocket. And maybe you want the magnets out of the magnetron. Be carful not to bust or scratch that ceramic thing. Sometimes they contain beryllium or barium (I dont remember which, but its highly carcenogic).
Oh man, I'm going to learn so much from a Ben Krasnow 'applicable magnetism' video, I've always hoped for a topic along those lines. Astounding content as always, you're one of the minority of youtubers that is still embracing quality over quantity.
Can't wait for the video on core materials! This has always been a fascination of mine. With all of the different properties of permeability, saturation, and hysteresis; there are nearly unlimited core types, each suited for specific applications.
I believe the one spectral line initially is actually two very very close to each other, as electrons with different spin already have very slightly different energy levels. The magnetic field will massively exacerbate this difference. What an awesome experiment. Thanks for spending so much effort and time to build all that.
I can’t wait until your video on magnetism. My high school physics class briefly touched on it but it left me with more questions than answers. And I’m sure that even if my specific questions aren’t answered in the video I will still learn some thing.
Your experiment made me wonder if the flame from the candle was an ionized gas, and that’s what was causing the flame deflection in the magnetic field. To test my idea, I put a candle flame between two aluminum plates about 1/4” apart and applied about 200 volts dc (power supply max.) across the plates. As I switched the voltage on/off, movement of the flame was quite noticeable. I bow to better minds than my own, but this and your magnetic deflection makes me believe we are working with an ionized gas.
Thank you for explaining your setup and how you built the ballast for the LPS lamp. That is exactly what I needed to make one to view interference patterns with optical flat!!!
i love how you learned stuff too. stops it all from being so intimidating. good on ya dude you're one of my heroes. dont stop doing what ya doing. -pepe
Great video! Just one thing, the Zeeman effect is about spectral lines (so electrons), mri is about nuclear resonance. You probably already know that and just used the comparison for the sake of the explanation but, as a chemist, I couldn't stay quiet :)
batcathatsatchat actually it's a different transition. Spectral lines come from the transition between orbitals, nmr exploits nuclear spin. There's an equivalent electron spin spectroscopy to nmr, but it has nothing to do with spectral lines. In a sense they are all a response to em radiation, but in different ways.
I was just thinking about how you haven't uploaded in a while, and then you upload this. I truly love your content. It's always bound to be interesting.
hang on a minute.... are you sure the mag field isn't deflecting the flame ? ... the ions of the flame will be moved by a mag field so surely the flame will be deflected.
Magnetic fields won't affect the position of a flame. We can explain this phenomenon with Quantum Mechanics, and can be seen to much higher precision with better instruments.
I've seen a flame split with electrostatic fields... that implies that you could split it the other way with a large magnetic field. Flame contains positive and negative ions travelling upwards, so wouldn't the flame split or widen in the presence of a strong magnetic field? Lorentz force and all.
@Evil Deeds well you guys are obviously idiots. When you factor in Lyman-alpha transition in hydrogen and if the spin-orbit interaction dominates over the effect of the external magnetic field, well a anomalous magnetic dipole moment will occur during Muon decay. Clearly, I mean this is common sense here
I am so glad I have chosen to follow your experiments. I am learning stuff and you make it so easy and clear. Thanks. I'm staying right with you. Please continue.
The reason your magnet core is getting so hot is because the core is made of conductive iron, and you have welded the two halves directly together. This completes the electrical circuit in your iron core. Essentially, your iron core is acting like a secondary coil that you've shorted out. It's only one turn, so it has a low voltage but high current. When using iron cores, you must break the electrical circuit, while doing to the least violence to the magnetic circuit. This is usually done with a piece of hardboard between the E and I parts of the outer ring of the core, usually just the center and one side but sometimes on all three connections. This isn't necessary on non-conductive cores like ferrite or air, but it is on iron. Note that while this is the reason for the break in conductive cores, it's not the reason for breaks in ferrite cores. Those breaks are to change the shape of the B-H curve, usually to increase the energy stored in the magnetic field, usually in flyback transformers. Breaks to change B-H curves are usually sized very precisely and require calibration. Breaks in iron cores usually aren't so careful.
Seeing your lab setup tells me you think faster than you can build the different apparatuses your using. Some out there should design a lab That is much faster something that each part is reconfigurable but fits together solid. However your doing a great job at combining speed efficiency and functionality. Keep up the good work!
Ben, Nice demo -- Exactly how my Rubidium frequency standard works. It uses a ~6Ghz signal to excite the Rubidium gas to absorb one of the spectral lines from a Rubidium lamp. Also there is a magnetic coil around the absorption cell to allow some amount of tweaking of center frequency or for temp compensation via the Zeeman Effect.It's cool to have a piece of equipment that contains a "Physics Package" at its heart. Craig in Sunnyvale. Would love to eyeball some time.
The phenomenon of ions absorbing the light from a gas discharge lamp that uses the same ions is also an important part of the rubidium gas cell, which is at the heart of pretty much the cheapest kind of atomic clock you can build. In that case, hitting the gas cell with microwaves of exactly the right frequency changes the amount of absorption, due to hyperfine splitting, and looking for that absorption peak allows calibrating the microwave frequency very precisely.
You don't need large magnetic field to get Zeeman effect. In HeNe lasers, the Zeeman effect is exploited to allow the red line to operate. Normally, in longer lasers, the 4 micron line dominates, because its gain is on the order of millions versus the 1.05 gain in the red. This is because of another wavelength-shifting effect, doppler shift. Doppler shift is proportional to frequency, so the red line is shifted 7 times more, leading to the lower gain. By putting small, weak, permanent magnets next to the laser tube, the 4 micron line is broadened because of the "random" nature of the field. So a complicated problem is solved by "simple, sloppily-placed, weak, magnets". You don't polarize the light. Zeeman effect is function of relative orientation of polarization and axis of the magnetic field. You probably get stronger visual effect adding polarizing filter. Have you tried putting sodium in glass tube, sealing it, and heating one end?
Nice. But I'm not convinced Zeeman is responsible. The problem is the subtle line shift, even with very strong magnetic fields, of the Zeeman effect. For your 1T, the split might be some 0.05nm wavelength. The line width of the low pressure sodium light source is some 100x this value at 5nm or so. Not saying the absorption modulation isn't real; it clearly is. Perhaps the velocity of the ionized flame traversing the magnetic field has set up an electric field strong enough to induce the Stark effect, which is more easily realized. The demonstration is dramatic, but there are a number of confounding factors in play.
Agreed. Stark is a stretch too. My point is there is no shortage of alternative hypotheses to explain the winking light. Clearly the flame absorption is broad enough to be visible using an inexpensive diffraction grating. A sanity check would be to set up a similar demonstration using white light, but with the flame in a magnetic field. If it is just Zeeman in play, we expect the line to spawn a broader family of lines (although there will not be sufficient dispersion to resolve). Alternatively, the magnetic field might simply quench the Fraunhofer line wholesale. That would indicate a different phenomena is responsible.
Are you sure linewidth of low pressure lamp must be around 5 nm? I can't find any evidence doing quick google search. However this article ("The width of the D absorption lines in sodium vapor") suggests that linewidth is about 0.4 nm at 400 C (and about 0.05 at 290 C) . I am not sure how to compare pressures, however if it's just equilibrium vapor pressure, we need to compare only temperatures. What's the temperature of sodium vapour inside these lamps?
It just occurred to me that your demonstration of sodium ions blocking a line of light in the spectrum is the way elements were discovered in the sun including a never before seen element Helium.
I think it would be good to clarify that your demo involves electron transitions but NMR or MRI involves nuclear transitions. I didn't realize that this effect extended to those but the Wikipedia article agrees with you.
Great video as always, but to be clear, the magnetic field does not affect the light directly, it changes the light and its polarization by affecting the material the emits light. Let me know if got this wrong, and thanks again for sharing all your awesome work with us.
You got that right. One could, theoretically, polarize the vacuum and see similar effects, but the required strong fields are, if at all, only available near neutron stars. I would have to look up if anybody has observed an astrophysical signal that is the result of such a vacuum polarization.
The trick with adding salt to oil lamps in order to get a brighter stable and sot free flame was used in antiquity e.g. when decorating vaults where you didn't want sot on ceilings.
The magnetic effect here is the motion of charged particles in a magnetic field, that's why the flame intensity is changing. The charged particles will start moving in circles when the magnetic field is introduced. The flame is very hot, the emission spectrum of atoms and black body radiation is adding up and making a white light at the hot bottom side, orange in the middle, and reddish on the outer side, that's why the colors do not match. This is the reason you have broad RGB colors on your grating 3:40. To observe the Zeeman effect, you need to observe spectral lines, in this case with the only 1T you are going to need a very high-resolution spectrometer with picometer resolution or a very high efficient grating with enough distance to observe the angle difference between the adjacent emission lines that are split. Your splitting will be at the order of the +-0.0x nm level.
5:05 sodium always has 2 lines, even without a magnetic field. Try passing a collimated sodium beam through a grating, then detecting it with a CMOS camera in second order. You should be able to see 2 lines. The lines are about 0.6nm apart.
I think that this effect works on the basis of phase rotation! A magnetic field aligns the light in one plane, makes the light polarized! There is a way to check my hunch))) remove the polarizing plastic film from the passive stereo glasses for a 3D movie and look through it, most likely, twisting it, you can completely turn off the light coming from the lamp through the magnetic flux! I’m also sure that more powerful magnets can rotate the phase of the waves of emitted light, so strongly by 180 degrees, from this the light can absorb itself
Trillions like and best comment for you because you are best on Earth and follower respect you,we need videos in Real 120fps or 240fps 4K,8K and Sound in FullHD Surrounded
If you had the permanent magnets on a wide horseshoe, with (tapered to increase time before heat conducts to the magnets?) iron pole pieces that go right next to the flame and reach equilibrium temperature, and then a switchable break in the crook of the horseshoe, you'd have a pretty elegant apparatus.
Super excited for the next video! I've been designing a permanet magnet(PM) coilgun, and have been struggling with the choice of all kinds of material.
Your explanation implies that the flame should be less opaque with the magnet ON but it looks to me like the light overall is getting darker when the magnet is ON (I am assuming that the downward movement of the object at the top of the coil corresponds to magnet ON)
I really enjoyed your demonstration of the Zeeman effect on Sodium lighting. Your use of a diffraction grating clearly showed the spreading out of the spectral lines in the gas. Clever construction of the electromagnet caught my eye, I have used those microwave transformers as well but never knew you could get a 10600 gauss field from them in that way without overheating the magnetic circuit core by eddy currents and the fact that the core material is driven hard into saturation. That would explain the current draw and its impedance. What I'd like to see is the ferromagnetic resonances (such as with isotopes of iron, perhaps fe^59?? not sure of my bandgap and isotope number there!!) using Larmor precessional values of the iron itself. Perhaps an rf amplifier would show those effects and if tuned with a low frequency pulsed direct current at low frequency (adiabatic invariance over the fundamental resonance of an infinite long slab) the double resonant Overhauser effect may show. Lots of integrals flying around there, but an amazing show of the torque of a compose compressed and twisted field line (at saturation!!) decoupling protons from the nucleus. Amazing video. I hope you do more.
One idea: do this with an RF excited Rb lamp and try to find the CPT point with another Rb lamp, heated, but not excited with high RF power, but excited with a low microwave source matching the CPT point. Essentially DIY a Rb atomic clock.
also neodymium is not fond of being heated by an oxi torch :) you would end up with a really weak magnet in no time :) neos's are the worsed in that regard. Oh i forgot to add, still great video as always ! im enjoying your content to the max, some way above my pay grade but hell :) fun either way :)
DarkIzo You can mostly demagnetize a standard N52 using only boiling water. 80°C is the point where permanent demagnetization begins, although it varies with the form factor of the magnet. Kind of hard to remagnetize too, you need about 5 Teslas.
That's why I use SmCo magnets in places where they may get warm (e.g. in a magnetron sputtering source, ion sources etc). Weaker and more expensive but can withstand temperatures up to 250C.
stamasd The newer SmCo (2-17) can be made about as strong as an N30 grade NdFeB magnet at room temperature, and has a max temperature of 300 - 350°C depending on the formulation.
I guess you could use a second flame with sodium for the demonstration instead of the sodium lamp. Normally each flame will obscure the other, but if you apply the magnetic field on one of the flames, _both_ should obscure each other less. You could also use hydrogen flames which are essentially invisible to the eye to diminish the contribution of other wavelengths.
I think you can combine the permanent and electromagnets so that current in one direction cancels the permanent magnet field and reversing the current doubles the field. Should be able to get 0-1.6T if the magnet doesn't saturate.
Awesome, Ben! The sodium emission lines are fascinating to me. I've read somewhere that San Diego county previously required all street lights to be LP or HP sodium arc so that their emissions wouldn't obstruct Palomar Observatory. IIRC Keck (and many other observatories) use sodium guide star lasers for the sharp emission lines.
The street light thing is related to light pollution. Requiring the nearby cities to use sodium lights (particularly low pressure) is because it is easier to filter out specific colors ( with very fine spectral lines) than a broad spectrum of light. And we need to filter out that light pollution because it's spreading over a large portion of the local sky and preventing telescopes to see the dimest details of the celestial objects they are looking at. It's an issue for scientific observatories but it is also a big issue for every amateur astronomer.
For giggles and to show a friend what the sodium light looks like, I made this photograph about 6 years ago. It's facing north from one of the hills near the apartment where I lived at the time (which was a little off of the right side of the image.) randomer.net/stuff/sodium-sm.jpg It's mostly LP sodium lights, but there are some mercury vapor lights on the right side. :)
Light pollution is definitely a huge problem for astronomy (researchers and hobbyists alike!) Filtering the 2 sharp spectral lines of sodium is fairly easy. For street lighting (the regulations in SD seem to have been relaxed, progressively, several times) LEDs are now the norm.
offtopic, please read. use those 2 electromagnets, connect them to 2 plates and drive them in high voltage resonant frequency so you make an AC MHD propulsion drive. Try it in salty water and you should get amazing results, since mitsubishi wanted to use this AC system but i suspect were stopped by military industrial compley and went the DC route which yeeld electrolosys (DC 8 knots instead of 100 knots AC system)
Great video! If you were to talk about hysteresis on next video I would love it. I'm currently learning about induction motors and it amazes me how many approximations are needed to be done. Up until the point of disregarding hysteresis all together; I guess if you are designing one you need to take it into account, but the textbook I'm following has no room for motor design.
If he wanted to check if the flames was moved by he field and not the actually changing he orbitals he could use a high speed camera as the time scale for the zeeman effect would be instant on the camera while the you could see the flame move up or down
I am suspicious that the magnetic field is affecting the gas flow from the acetylene flame. This would be much more impressive with a couple of frequency stabilised lasers to demonstrate that this was not simply a deflection of charged ions.
If it does affect it, the ions should be shifted forward / backward in the optical path, not side to side. I doubt there would be any detectable change in the amount of sodium in the optical path. It would be interesting to see if you can actually produce a visible effect on a flame using just a magnetic field. I've seen it done using a strong electric field. (Edit) Did a bit of searching, apparently Faraday did some experiments on this in 1847 after he heard about it from the Italians. A magnetic field definitely does affect the flame, and more than I thought. If you scan through this link: www.researchgate.net/publication/224728281_Effects_of_magnetic_fields_on_flames_and_gas_flow you can find several papers relating to the subject.
timbargen - I am thinking of an experiment that involves splitting a laser beam and recombining it to produce a constructive and destructive interference pattern. A strong magnetic field is applied to one leg of the beam and a change should be observed in the pattern. In theory it should be possible to turn laser light arriving at a target on or off by applying a magnetic field, even though light is travelling in both legs of the path to the target.
I think my head just exploded from how interesting that is.
Agreed, also love your videos
This
The last 2 minutes alone contained more information than most people absorb in a lifetime.
I am so, so glad you two people know of each other
Oh you didn't know all that stuff already?
Hello Ben, I can not believe it. My channel is booming !!! Thank you very much ... The MOT Magnet is a great idea!
Many thanks also to the many new subscribers of my channel - I am thrilled!!! :-)
xofunkox-scientific experiments hahah wow i read ur comment exactly as he dropped your name.
@@decrodedart2688 wow same happened with me
Each and every video of yours is so thoroughly prepared and thought through, it's amazing! And I love how you make everything very hands-on
Adding light to light to make shadows...
optical interference
Fighting light with fire!
"Thin Film Interference" Harvard Natural Sciences Lecture Demonstrations
@sirati97 light is not ions...ions cast shadows, because they are particles, photons are not particles.
Just learned about this last semester in my electric, magnetic, & optic properties of materials class. Great demo!
Know what do you know lol
The only reason you don't have a couple of million subscribers is because your topics are too complicated for the mainstream.
But those who understand your topics (your videos) appreciate every single one.
Thanks a lot for all your work.
Very nice!. You take a lab curiosity and make it an undeniable, macroscopic demonstration. I will be very interested in your video on magnetic materials. We are building a large, permanent magnetic yoke to demonstrate magneto-hydrodynamic principles and applications. The magnets are easy, the steel and engineering are not. Cheers.
Such a great straight-forward demonstration! They should have used this for my undergraduate intermediate physics lab.
Can't wait for the next video Ben, and glad you gave Funk's channel a shout-out, they've had consistently awesome practical physics demonstrations for ages, highly recommended
Btw. Here's a tip on getting. Microwave oven transformers.
If you go to one of the electronic recycling days ( usually in supermarket parking lots on a specified weekend) the items that are usually dropped off are printers, monitors, and Microwaves. Almost all microwave ovens stop working b/c the magnatron burns out. Meaning the transformer is more than likely good. Slip the guy $10 or $20 and ask the guy for a couple transformers. Bring the necessary tools, dont make a mess, try to be inconspicuous, and try to reassemble it after you take it out. I asked the guy what they do with all that stuff. He said they all go in a big shredder, so it doesnt matter whats left in them.
I managed to get 4 MOTs for $10. I could have got more, but I didnt wanna get him in trouble with his boss. A friendly reminder. The capacitors in microwave ovens can be hazardous even when not plugged in. Make sure the first thing you do when you get it opened is arc the cap with a screwdriver with one hand and other hand in your pocket. And maybe you want the magnets out of the magnetron. Be carful not to bust or scratch that ceramic thing. Sometimes they contain beryllium or barium (I dont remember which, but its highly carcenogic).
Oh man, I'm going to learn so much from a Ben Krasnow 'applicable magnetism' video, I've always hoped for a topic along those lines.
Astounding content as always, you're one of the minority of youtubers that is still embracing quality over quantity.
Can't wait for the video on core materials! This has always been a fascination of mine. With all of the different properties of permeability, saturation, and hysteresis; there are nearly unlimited core types, each suited for specific applications.
The narrow band of light missing was so cool. That was a great way to show this off.
Thank you for this videos! Next generations of scientists are very lucky to have you!
I believe the one spectral line initially is actually two very very close to each other, as electrons with different spin already have very slightly different energy levels. The magnetic field will massively exacerbate this difference.
What an awesome experiment. Thanks for spending so much effort and time to build all that.
That's so interesting and an interesting way to encode more information into light signals
Love the use of the microwave transformers. 1.2 Tesla. That's pretty good.
my favorite channel over the course of years
I can’t wait until your video on magnetism. My high school physics class briefly touched on it but it left me with more questions than answers. And I’m sure that even if my specific questions aren’t answered in the video I will still learn some thing.
Your experiment made me wonder if the flame from the candle was an ionized gas, and that’s what was causing the flame deflection in the magnetic field.
To test my idea, I put a candle flame between two aluminum plates about 1/4” apart and applied about 200 volts dc (power supply max.) across the plates. As I switched the voltage on/off, movement of the flame was quite noticeable.
I bow to better minds than my own, but this and your magnetic deflection makes me believe we are working with an ionized gas.
Thank you for explaining your setup and how you built the ballast for the LPS lamp. That is exactly what I needed to make one to view interference patterns with optical flat!!!
i love how you learned stuff too. stops it all from being so intimidating. good on ya dude you're one of my heroes. dont stop doing what ya doing. -pepe
Zeeman effect is a fundamental quantum mechanical effect. This demo is beautiful.
Great video! Just one thing, the Zeeman effect is about spectral lines (so electrons), mri is about nuclear resonance. You probably already know that and just used the comparison for the sake of the explanation but, as a chemist, I couldn't stay quiet :)
It's the same thing, just at different frequencies. An electron splits at 28GHz per Tesla, a proton splits at 42MHz per Tesla.
batcathatsatchat actually it's a different transition. Spectral lines come from the transition between orbitals, nmr exploits nuclear spin. There's an equivalent electron spin spectroscopy to nmr, but it has nothing to do with spectral lines. In a sense they are all a response to em radiation, but in different ways.
I was just thinking about how you haven't uploaded in a while, and then you upload this. I truly love your content. It's always bound to be interesting.
hang on a minute....
are you sure the mag field isn't deflecting the flame ? ... the ions of the flame will be moved by a mag field so surely the flame will be deflected.
Magnetic fields won't affect the position of a flame. We can explain this phenomenon with Quantum Mechanics, and can be seen to much higher precision with better instruments.
Also kids do not do this at homr because omg the mercury in that broken flourescent please tell me you did that cleanly in a lab?
@@Billy-mj9jf ions are deflected by a magnetic field - it's the fundamental principle behind a generator
I've seen a flame split with electrostatic fields... that implies that you could split it the other way with a large magnetic field. Flame contains positive and negative ions travelling upwards, so wouldn't the flame split or widen in the presence of a strong magnetic field? Lorentz force and all.
@Evil Deeds well you guys are obviously idiots. When you factor in Lyman-alpha transition in hydrogen and if the spin-orbit interaction dominates over the effect of the external magnetic field, well a anomalous magnetic dipole moment will occur during Muon decay. Clearly, I mean this is common sense here
I am so glad I have chosen to follow your experiments. I am learning stuff and you make it so easy and clear. Thanks. I'm staying right with you. Please continue.
The reason your magnet core is getting so hot is because the core is made of conductive iron, and you have welded the two halves directly together. This completes the electrical circuit in your iron core. Essentially, your iron core is acting like a secondary coil that you've shorted out. It's only one turn, so it has a low voltage but high current. When using iron cores, you must break the electrical circuit, while doing to the least violence to the magnetic circuit. This is usually done with a piece of hardboard between the E and I parts of the outer ring of the core, usually just the center and one side but sometimes on all three connections. This isn't necessary on non-conductive cores like ferrite or air, but it is on iron.
Note that while this is the reason for the break in conductive cores, it's not the reason for breaks in ferrite cores. Those breaks are to change the shape of the B-H curve, usually to increase the energy stored in the magnetic field, usually in flyback transformers. Breaks to change B-H curves are usually sized very precisely and require calibration. Breaks in iron cores usually aren't so careful.
Its an incredibly simple but ingenious way to see the Zeeman effect.
Seeing your lab setup tells me you think faster than you can build the different apparatuses your using. Some out there should design a lab
That is much faster something that each part is reconfigurable but fits together solid. However your doing a great job at combining speed efficiency and functionality. Keep up the good work!
Ben, Nice demo -- Exactly how my Rubidium frequency standard works. It uses a ~6Ghz signal to excite the Rubidium gas to absorb one of the spectral lines from a Rubidium lamp. Also there is a magnetic coil around the absorption cell to allow some amount of tweaking of center frequency or for temp compensation via the Zeeman Effect.It's cool to have a piece of equipment that contains a "Physics Package" at its heart.
Craig in Sunnyvale. Would love to eyeball some time.
Not exactly right. The magnetic field is applied to the _source_ of the light (the Rb bulb), not to the light itself.
I need to watch this again .... too much information for my little brain that really wants to learn....thank you sir, your experiments are awesome.
The phenomenon of ions absorbing the light from a gas discharge lamp that uses the same ions is also an important part of the rubidium gas cell, which is at the heart of pretty much the cheapest kind of atomic clock you can build. In that case, hitting the gas cell with microwaves of exactly the right frequency changes the amount of absorption, due to hyperfine splitting, and looking for that absorption peak allows calibrating the microwave frequency very precisely.
You don't need large magnetic field to get Zeeman effect. In HeNe lasers, the Zeeman effect is exploited to allow the red line to operate. Normally, in longer lasers, the 4 micron line dominates, because its gain is on the order of millions versus the 1.05 gain in the red. This is because of another wavelength-shifting effect, doppler shift. Doppler shift is proportional to frequency, so the red line is shifted 7 times more, leading to the lower gain. By putting small, weak, permanent magnets next to the laser tube, the 4 micron line is broadened because of the "random" nature of the field. So a complicated problem is solved by "simple, sloppily-placed, weak, magnets".
You don't polarize the light. Zeeman effect is function of relative orientation of polarization and axis of the magnetic field. You probably get stronger visual effect adding polarizing filter. Have you tried putting sodium in glass tube, sealing it, and heating one end?
Nice. But I'm not convinced Zeeman is responsible. The problem is the subtle line shift, even with very strong magnetic fields, of the Zeeman effect. For your 1T, the split might be some 0.05nm wavelength. The line width of the low pressure sodium light source is some 100x this value at 5nm or so. Not saying the absorption modulation isn't real; it clearly is. Perhaps the velocity of the ionized flame traversing the magnetic field has set up an electric field strong enough to induce the Stark effect, which is more easily realized. The demonstration is dramatic, but there are a number of confounding factors in play.
I'm also not convinced that self-induced Stark effect would be the culprit.
Agreed. Stark is a stretch too. My point is there is no shortage of alternative hypotheses to explain the winking light. Clearly the flame absorption is broad enough to be visible using an inexpensive diffraction grating. A sanity check would be to set up a similar demonstration using white light, but with the flame in a magnetic field. If it is just Zeeman in play, we expect the line to spawn a broader family of lines (although there will not be sufficient dispersion to resolve). Alternatively, the magnetic field might simply quench the Fraunhofer line wholesale. That would indicate a different phenomena is responsible.
Are you sure linewidth of low pressure lamp must be around 5 nm? I can't find any evidence doing quick google search. However this article ("The width of the D absorption lines in sodium vapor") suggests that linewidth is about 0.4 nm at 400 C (and about 0.05 at 290 C) . I am not sure how to compare pressures, however if it's just equilibrium vapor pressure, we need to compare only temperatures. What's the temperature of sodium vapour inside these lamps?
I'd like to mention also that self-induced Stark effect requires very high intensities and I think usually observed with lasers.
Hyperfine broadening?
It just occurred to me that your demonstration of sodium ions blocking a line of light in the spectrum is the way elements were discovered in the sun including a never before seen element Helium.
So interesting!
you're alive lol
but most of all, samy is my hero
therealnightwriter Please don't tell me you're one of those Electric Universe nut jobs.
Great demonstration once again! Also very cool to know that application of the Zeeman effect in sunspots. :)
Yet another excellent video... a perfect demonstration and clear explanations of everything involved! Keep em coming!
Cool stuff, I always appreciate your videos on any subject, well done.
this is why red shift is not a good indicator of speed or distance of stars.
space is filled with electric and magnetic fields
I think it would be good to clarify that your demo involves electron transitions but NMR or MRI involves nuclear transitions. I didn't realize that this effect extended to those but the Wikipedia article agrees with you.
I am always so impressed by the effort you go to to make these videos. Legend :)
Great video as always,
but to be clear, the magnetic field does not affect the light directly, it changes the light and its polarization by affecting the material the emits light.
Let me know if got this wrong, and thanks again for sharing all your awesome work with us.
You got that right. One could, theoretically, polarize the vacuum and see similar effects, but the required strong fields are, if at all, only available near neutron stars. I would have to look up if anybody has observed an astrophysical signal that is the result of such a vacuum polarization.
That's a really awesome way to demonstrate that effect!
The trick with adding salt to oil lamps in order to get a brighter stable and sot free flame was used in antiquity e.g. when decorating vaults where you didn't want sot on ceilings.
+1 for having your power strip (on the front of the bench) oriented the proper way (earth pin up).
Always something fascinating happening within applied science.
It's really nice to original experiment
You're awesome as per usual. Looking forward to your next video on magnetism.
Good to hear about the next video! I'm working on a multistage coil gun.
Looking forward to that next video
The magnetic effect here is the motion of charged particles in a magnetic field, that's why the flame intensity is changing. The charged particles will start moving in circles when the magnetic field is introduced. The flame is very hot, the emission spectrum of atoms and black body radiation is adding up and making a white light at the hot bottom side, orange in the middle, and reddish on the outer side, that's why the colors do not match. This is the reason you have broad RGB colors on your grating 3:40. To observe the Zeeman effect, you need to observe spectral lines, in this case with the only 1T you are going to need a very high-resolution spectrometer with picometer resolution or a very high efficient grating with enough distance to observe the angle difference between the adjacent emission lines that are split. Your splitting will be at the order of the +-0.0x nm level.
you have a great setup and an excellent way of explanation
Now that's the internet has really been invented for! Great channel, keep it up!
5:05 sodium always has 2 lines, even without a magnetic field. Try passing a collimated sodium beam through a grating, then detecting it with a CMOS camera in second order. You should be able to see 2 lines. The lines are about 0.6nm apart.
Keen on an electromagnetism episode!
Great stuff... next one sounds even better.
I think that this effect works on the basis of phase rotation! A magnetic field aligns the light in one plane, makes the light polarized! There is a way to check my hunch))) remove the polarizing plastic film from the passive stereo glasses for a 3D movie and look through it, most likely, twisting it, you can completely turn off the light coming from the lamp through the magnetic flux! I’m also sure that more powerful magnets can rotate the phase of the waves of emitted light, so strongly by 180 degrees, from this the light can absorb itself
Every patreon's got his 1/10th second of glory :-)
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If you had the permanent magnets on a wide horseshoe, with (tapered to increase time before heat conducts to the magnets?) iron pole pieces that go right next to the flame and reach equilibrium temperature, and then a switchable break in the crook of the horseshoe, you'd have a pretty elegant apparatus.
Your video put my brain into MPMM (Massively Paralleled Microprocessor Mode)
Super cool your electromagnet......
Super excited for the next video! I've been designing a permanet magnet(PM) coilgun, and have been struggling with the choice of all kinds of material.
Awesome video, I'll try building an powerful magnetic source and try seeing theses changes with my spectrometer.Thanks for the great content
Just gotta say that I appreciate the 60fps recording method! And that's a seriously strong magnetic field at 1.2 Teslas! :O
This looks like a fun way to make a varying light source for a mechanically scanned television.
Looking forward to the next video. Sounds like a neat topic.
This is what made loki bite the eyebrow of the dwarf
For reference, most phones have field meters for orientation. Really handy.
I look forward for youre upcoming video. I wish to know much more about making the most out of an electromagnet
Great video & topic. I'm looking forward to the next one you mentioned, too!
Your explanation implies that the flame should be less opaque with the magnet ON but it looks to me like the light overall is getting darker when the magnet is ON (I am assuming that the downward movement of the object at the top of the coil corresponds to magnet ON)
I really enjoyed your demonstration of the Zeeman effect on Sodium lighting. Your use of a diffraction grating clearly showed the spreading out of the spectral lines in the gas.
Clever construction of the electromagnet caught my eye, I have used those microwave transformers as well but never knew you could get a 10600 gauss field from them in that way without overheating the magnetic circuit core by eddy currents and the fact that the core material is driven hard into saturation. That would explain the current draw and its impedance. What I'd like to see is the ferromagnetic resonances (such as with isotopes of iron, perhaps fe^59?? not sure of my bandgap and isotope number there!!) using Larmor precessional values of the iron itself. Perhaps an rf amplifier would show those effects and if tuned with a low frequency pulsed direct current at low frequency (adiabatic invariance over the fundamental resonance of an infinite long slab) the double resonant Overhauser effect may show. Lots of integrals flying around there, but an amazing show of the torque of a compose compressed and twisted field line (at saturation!!) decoupling protons from the nucleus.
Amazing video. I hope you do more.
What
Wow, amazing, loved it. Also can you do a video on stark effect?
I haven’t checked if you did but yea
can't wait for your magnet video. fill me with your knowledge!
Pretty cool. I hadn't heard of that effect before this video.
One idea: do this with an RF excited Rb lamp and try to find the CPT point with another Rb lamp, heated, but not excited with high RF power, but excited with a low microwave source matching the CPT point. Essentially DIY a Rb atomic clock.
This give me a idea to use in my lasers.
Shop fire in 3...2...1...
Seriously though so many flammable things on that bench.
I was just looking into this, thank you!
3:57 is EPIC...!!
Great video, thank you! It's realy interesting that there is actually a use for this lesser known effect.
Excellent work mate. A lot of effort and great explanations.
also neodymium is not fond of being heated by an oxi torch :) you would end up with a really weak magnet in no time :) neos's are the worsed in that regard.
Oh i forgot to add, still great video as always ! im enjoying your content to the max, some way above my pay grade but hell :) fun either way :)
neos are always the worst :P
DarkIzo You can mostly demagnetize a standard N52 using only boiling water. 80°C is the point where permanent demagnetization begins, although it varies with the form factor of the magnet.
Kind of hard to remagnetize too, you need about 5 Teslas.
That's why I use SmCo magnets in places where they may get warm (e.g. in a magnetron sputtering source, ion sources etc). Weaker and more expensive but can withstand temperatures up to 250C.
stamasd The newer SmCo (2-17) can be made about as strong as an N30 grade NdFeB magnet at room temperature, and has a max temperature of 300 - 350°C depending on the formulation.
I guess you could use a second flame with sodium for the demonstration instead of the sodium lamp. Normally each flame will obscure the other, but if you apply the magnetic field on one of the flames, _both_ should obscure each other less. You could also use hydrogen flames which are essentially invisible to the eye to diminish the contribution of other wavelengths.
Lol there are so many cool individual scientific effects on light and matter.
I could have used this in sooo many places.
I think you can combine the permanent and electromagnets so that current in one direction cancels the permanent magnet field and reversing the current doubles the field. Should be able to get 0-1.6T if the magnet doesn't saturate.
Temporal Quantum-field of e-Pi-i probability, 0-1-2-3-4-etc exponentiation-ness, is Everything from mass-energy-momentum to AdS/CFT Holographic condensation-> superposition line-of-sight modulation=> Zeeman cause-effect.
Excellent Sciencing
"Ah, I thought it was one of the prime numbers of the Zeeman series. I haven't changed!" - Dr. Hans Zarkov
Awesome, Ben! The sodium emission lines are fascinating to me. I've read somewhere that San Diego county previously required all street lights to be LP or HP sodium arc so that their emissions wouldn't obstruct Palomar Observatory. IIRC Keck (and many other observatories) use sodium guide star lasers for the sharp emission lines.
The street light thing is related to light pollution. Requiring the nearby cities to use sodium lights (particularly low pressure) is because it is easier to filter out specific colors ( with very fine spectral lines) than a broad spectrum of light. And we need to filter out that light pollution because it's spreading over a large portion of the local sky and preventing telescopes to see the dimest details of the celestial objects they are looking at. It's an issue for scientific observatories but it is also a big issue for every amateur astronomer.
For giggles and to show a friend what the sodium light looks like, I made this photograph about 6 years ago. It's facing north from one of the hills near the apartment where I lived at the time (which was a little off of the right side of the image.) randomer.net/stuff/sodium-sm.jpg It's mostly LP sodium lights, but there are some mercury vapor lights on the right side. :)
Light pollution is definitely a huge problem for astronomy (researchers and hobbyists alike!) Filtering the 2 sharp spectral lines of sodium is fairly easy. For street lighting (the regulations in SD seem to have been relaxed, progressively, several times) LEDs are now the norm.
If you have some way to chill those electromagnets with something like dry ice or liquid nitrogen, you can increase the strength of them substantially
Reminds me of mercury vapour shadows from a mercury vapour lamp.
Aaah takes me back to when I was learning physics at school and pinching wire and stuff to experiment with...
offtopic, please read.
use those 2 electromagnets, connect them to 2 plates and drive them in high voltage resonant frequency so you make an AC MHD propulsion drive. Try it in salty water and you should get amazing results, since mitsubishi wanted to use this AC system but i suspect were stopped by military industrial compley and went the DC route which yeeld electrolosys (DC 8 knots instead of 100 knots AC system)
Great video! If you were to talk about hysteresis on next video I would love it.
I'm currently learning about induction motors and it amazes me how many approximations are needed to be done. Up until the point of disregarding hysteresis all together; I guess if you are designing one you need to take it into account, but the textbook I'm following has no room for motor design.
If he wanted to check if the flames was moved by he field and not the actually changing he orbitals he could use a high speed camera as the time scale for the zeeman effect would be instant on the camera while the you could see the flame move up or down
Looking forward to your next video!
I am suspicious that the magnetic field is affecting the gas flow from the acetylene flame. This would be much more impressive with a couple of frequency stabilised lasers to demonstrate that this was not simply a deflection of charged ions.
"Paging @Tech Ingredients, We'd like you to shoot lasers thru magnetic fields please" :) ua-cam.com/video/nMonZHMTra4/v-deo.html
If it does affect it, the ions should be shifted forward / backward in the optical path, not side to side. I doubt there would be any detectable change in the amount of sodium in the optical path.
It would be interesting to see if you can actually produce a visible effect on a flame using just a magnetic field. I've seen it done using a strong electric field.
(Edit) Did a bit of searching, apparently Faraday did some experiments on this in 1847 after he heard about it from the Italians. A magnetic field definitely does affect the flame, and more than I thought.
If you scan through this link:
www.researchgate.net/publication/224728281_Effects_of_magnetic_fields_on_flames_and_gas_flow
you can find several papers relating to the subject.
timbargen - I am thinking of an experiment that involves splitting a laser beam and recombining it to produce a constructive and destructive interference pattern. A strong magnetic field is applied to one leg of the beam and a change should be observed in the pattern. In theory it should be possible to turn laser light arriving at a target on or off by applying a magnetic field, even though light is travelling in both legs of the path to the target.
Michael Kaliski It sounds to me like you want to build some sort of interferometer. How would you use this to detect the Zeeman effect?