Plasmas and Rainbows!

[@trygveplaustrum4634]

Even when covering topics that I thought I understood, you effortlessly explain it from a perspective I never saw before! You folks are a blessing. I wish you success and subscribers, and I hope you continue to entertain us for many more years to come!

[@JeffersonLab]

Thanks! We hope you keep watching!

[@eltonronjovi2238]

When you make science accessible and fun, you have inspired a young mind to do incredible things. I thank you for this big time along with the hard work you all do that's beyond a lay persons understanding. Please continue to take us forward. 🙂

[@JeffersonLab]

We'll do our best!

[@michaelschwartz9485]

I can't believe how much I'm learning from you, and I'm 54!

[@Muonium1]

There is nothing quite like the immediacy of actually SEEING the individual quantum transitions of atoms in a plasma with a prism or grating. For the brighter kids who 'get it', it leaves a lasting impression. These look like early high school kids to me so it may be a bit early to introduce it, but if you use a Plucker tube of hydrogen, a subtle but fascinating secondary phenomenon also becomes visible. In the hydrogen tube, the current density within the bright capillary region of the tube is high enough that it's producing the typical and expected Balmer lines of hydrogen atoms, but if one observes the diffuse and dimmer regions of plasma at the wider ends of the tube where the current density is much lower, one can plainly see -in addition to the Balmer series a multitude of other lines, particularly in the yellow-orange region. What's happening? The current density is too low at the ends of the tube to dissociate the hydrogen MOLECULES there into their two constituent H atoms; so you're seeing energy transitions of the H2 *molecules*, not just the H atoms, which are vastly more complicated and produce an enormously larger number of transitions than the atom alone.

[@tk12exploresengineering]

this channel is just wonderful. i wish the presenter (Mr steve wagnon, if I'm not wrong) delivered physics lectures too

[@trygveplaustrum4634]

8:06 Was... was that a Spongebob reference? In a Jefferson Lab video? My brain needs a moment to process. Come back tomorrow.

[@JeffersonLab]

A few days later...

[@Muzamil_bhat]

In India we are still studying failed ancient theories 🥺

[@srivatsanraghunathan4359]

Which part of India yor are in? Fourty five years ago, we have done many fun experiments in small town school. I suggest you change your place inside indis

[@mohamedyaseen3061]

Hi vro

[@Caded82]

How often do you have those "lessons" and who is the audience? I wish I could join you one day (maybe as a visitor?). Greetings from Switzerland

[@JeffersonLab]

When there isn't a pandemic? Usually 3 or 4 times a month during the school year. The audience is intended to be students in 5th-8th grade, but that's not a strict requirement. If you're going to travel from Switzerland, then you'd want to time your visit to coincide with one of the Lab's Open Houses. Then, you'd be able to go into the accelerator and experimental areas. The Lab usually holds an Open House every two years (again, when there isn't a pandemic going on). You can keep an eye on this page [ www.jlab.org/openhouse ] for Open House information.

[@Caded82]

@@JeffersonLab thank you, it would be amazing!

[@hseverins]

Your lectures are very rare! Just like Walter Lewin! But with more humor

[@thetechrealms7824]

Great to see you guys back

[@trinity9365]

Thank you so much for the lesson.

[@JeffersonLab]

Not a problem!

[@shaguftaafroz2343]

Amaazzinggg!! Really Informative❤️!

[@burhanuddinsiamwala1022]

man this thing should be on netflix as a series

[@Darnash306]

Great video! This helps me a lot in Physics!

[@IMMORTALHYDRA]

Thanks sir for the knowledge 🙌

[@robertbackhaus8911]

Do you ever touch on the fluorescent tube being a mercury tube with a coating of many phosphors of all different colours?

[@JeffersonLab]

Not normally. Our colleagues at the Princeton Plasma Physics Lab convinced some flourescent bulb manufacturer to produce some bulbs that were only half coated with phosphors, so you could see the action of the mercury in one half and the 'normal' emissions in the other.

[@wendikl7179]

I've always wondered why RGB is used...shouldn't it be red, yellow and blue? (since green is already yellow and blue?)

[@JeffersonLab]

It's the difference between additive mixing (what you get with light) and subtractive mixing (what you get with dyes). Your computer monitor is RGB, but your printer is CYMK (cyan, yellow, magenta and black). If you want to see green on your computer screen, you just use green. If you want to print green, you mix cyan and yellow. The cyan absorbs red light and the yellow absorbs blue light, so when white light hits the mixture of cyan and yellow, only the middle portion of the spectrum, the green, is reflected. (white - cyan - yellow = green) Mixing all colors of light results in white (additive). Mixing all colors of dyes results in black (subtractive).

[@wendikl7179]

@@JeffersonLab Thank you so much for explaining subtractive mixing, I did not completely understand that! I still wonder why "they" wouldn't use RYB for additive color combinations instead since it seems more pure...🤔 would that be more of a technical question? I appreciate you!

[@JeffersonLab]

I'm just guessing here, but it might be because our eyes are most sensitive to (and the sun's spectrum peaks in) the green part of the spectrum. One place this pops up is in the design of digital cameras. The sensor in your phone's camera (and all digital cameras) is actually a black and white device. It only registers how much light falls on a particular pixel. To get color, they place color filters in front of each pixel. So, your camera effectively has red, green and blue pixels because of these filters. Since our eyes are most sensitive to green, the 'green' information is more valuable/useful than the red and the blue, so your camera actually contains as many green pixels as it does red and blue combined. You can do a search for 'Bayer Filter' for more details. And, apparently, Bayer considered using cyan, magenta and yellow, but appropriate dyes weren't available at the time. Although, apparently, there are some cameras today that use CMY Bayer Filters. Also, Sony added yellow pixels to one of their product lines (Quattron?) several ago. I can't imagine that would have been more than a marketing gimmick since, if it's receiving broadcasts just like everyone else, there wouldn't have been a 'yellow' channel encoded within it. It would be receiving RGB data, like everyone else.

[@wendikl7179]

@@JeffersonLab Very cool, thank you so much! I will look up Bayer filter and Sony Quattron 😋🍽

[@blackradbit]

Great video ! Thank you !

[@JeffersonLab]

Glad you liked it!

[@trygveplaustrum4634]

I want a copy of the Table of Elements...

[@JeffersonLab]

A link to the Table of Elements is included in the video's description. education.jlab.org/itselemental/tableofelementsc.pdf

[@willopenatclose]

Thanks for the warnings and timestamps by the way! This is really really good, more people should do it like this.

[@JeffersonLab]

Actually saw that in one of Jenny Nicholson's videos and thought it would be a good idea here, too.

[@CodesLK]

superb

[@seetavishwakarma9287]

The 5th state of matter is Bose-Einstein Condensate

[@otacilioribeiro8944]

great stuff

[@duckymomo7935]

Yay he’s alive

[@JeffersonLab]

If you want to get picky, this video only shows that he was alive when this was recorded back in early 2020. But, yes, he's still alive (at least as of the writing of this comment).

[@Aaaaraaa]

❤️👍👍❤️❤️😘

[@FellyEroma]

❤

[@EweChewBrrr01]

I would love a pair of those glasses. Can they be made at home easily or would I need a PhD in something sciency and access to highly restricted materials? I'm half expecting you to say "All you need is cling wrap." The other half is expecting to hear "You will need access to the hadron collider."

[@JeffersonLab]

Easy to make at home? No, not really. The plastic 'lenses' contain a hologram of parallel lines (actually, a few sets of parallel lines that are rotated relative to each other) that have been etched onto a glass plate and then shrunk down so that there are effectively several thousand lines per millimeter. However, they are not expensive to produce. The company we get them from is called Rainbow Symphony. You can check to see if they sell them in small lots. Or, you can Google 'diffraction glasses' or 'diffraction gratings' for other vendors.

[@TheMayank18]

So Deeply Hurting That His Hairs Are Turning White!!!

[@nightcore4345]

No comments?!

[@JeffersonLab]

You were just very early.

[@MaximusVergil]

why is this downvoted at 15k but only upvoted 430

[@JeffersonLab]

It isn't. At the time of posting this reply, it's 430 up and 3 down.