Plasma colors and structures of various Gases in a vacuum discharge tube

[@UDITKUMAR-gh1xc]

this video is uploaded 7 years ago but this is one of this best experimental illustration I ever seen .. ib this experiment we can easily watch the crookes dark space ( near catode ) , positive column fringes at very low pressure for different gases

[@jonni2734]

Incredibly beautiful!!

[@UDITKUMAR-gh1xc]

yes it is brother

[@Bobsry16]

The water, argon and helium tubes looks quite bright. Especially the water plasma!

[@zenphysician]

The water plasma is interesting, it flares out at the end closest to the cathode and seems to show some signs of amplification as it does so

[@thomasrussell4674]

My god I've been wondering so long what water vapour lamp would look like. I'd be interested to see if water spectra could be compared between DC and high frequency AC, I wonder if you could ever get a resonant frequency that maximises a cycle of water ionization.

[@nwsteg2610]

What type of glass tube is that? Does it have a special name? Great video, thanks!

[@rajdeep7124]

quartz

[@justinjoseph2685]

In the water vapor test, did water droplets accumulate in the glass tube? How long could that run without constant adjustment?

[@random3250]

How does the water one not explode? There should be electrolysis and then the plasma will ignite it the O and H2 gasses formed, right?

[@leonardpearlman4017]

Naaaah. There's almost nothing in there! It might be getting pretty warm in there, but there's nothing to detonate I think, this is like 1/100th of the atmospheric pressure.

[@CUBETechie]

What brightness does water have and what wavelength?

[@matthewhait4336]

are you changing the applied voltage level with respect to time, or is the alternating intensity of the light an artifact of the camera you are using?

[@acrakatau4365]

At the beginning the voltage isn't changed over time, but the pressure. The little red number in the corner is the pressure gauge (in mbar). At the end I tried to get the nicest plasma by adjusting the voltage a bit, therefore the plasma fluctuates in shape and light intensity.

[@ahlb4371]

What pressure gauge are you using ? thank you

[@bebrownbear8354]

Can i make sure that gas can glows when it conduct electricity right?

[@briangwills6188]

what are the applied voltages?

[@prometheus8567]

@julesdownunder KV

[@leonardpearlman4017]

@julesdownunder Just KILO VOLTS. Thousands of Volts. Thousands of VOLT-AMPS would be a lot of POWER, and enough to melt the tube and wires and everything. He's probably using like FIVE Volt-Amps (Watts).

[@ahlb4371]

What pressure gauge are you using ? thank you

[@MegaBanne]

Aren't those layers on the positive side just double layers. I think the reason why you have such strange behavior when it comes to the water is the mass difference between oxygen and hydrogen. This is in contrast with the mass difference between oxygen and carbon. The higher the mass of the ions more double layering you will find. That is why argon has the longest double layer and helium the shortest amongst the more stable plasmas. Due to the strange mixture of hydrogen and much heavier oxygen explains the unstable behavior. The column in the middle could be a column of oxygen, concentrated due Marklund Convection, while weak and unstable hydrogen double layers forms on the outside of the colum. Even the CO2 one tends to have rounder double layer disks than the ones with only one type of element in them. These columns of double layers probably don't end, they just goes from glow mode to dark mode.

[@danielprieto3563]

What are double layers

[@mariomills6175]

Is there any effect on Co2 that changes its chemical elements?

[@goldendragon776]

Thank you very much 😊

[@ajnavortex6641]

how you put water in the vacuum tube? is not a gas

[@acrakatau4365]

The water was inserted with a syringe through a needle in the silicone tubing. Due to the low pressure in the tube the water will evaporate even at room temperature and fill the whole discharge tube with water vapour/gas.

[@antoineblanchard]

water are condensate state in 1atm, but is a gas (h2o)

[@Khepramancer]

Acrakatau Any idea what the spectral output is with the water tube? Is it a heavy UV emitter?

[@piotrkeczar9139]

@@acrakatau4365 Can mixed gases such as helium and argon glow simultaneously? What density of the gas will give it the ability to glow? Will it glow when we mix it with gases such as oxygen or nitrogen?

[@leozendo3500]

First youve got to have a good pump.

[@john-allenduskglass3193]

thank you

[@scoutingkitalass]

Good

[@vmishev]

What about hydrogen?

[@acrakatau4365]

Hydrogen should look very similar to water, but not as white more bluish pink depending on the current density, but I haven't tested it in this setup yet.

[@MegaBanne]

It should behave very much differently. More stable.

[@antoineblanchard]

nice

[@mamelmulm]

How much German accent do you want? Yes

[@annaoaulinovna]

CO2 is the best