Follow up Sparky Challenge

John T

Well-known Member
Okay, heat and color wavelength and temperature etc is NOT my cup o tea, that's more for Physicist, Mechanical and Thermodynamics Engineers, but heres a "belief" I have which I hope some Mechanical or Thermo Engineer or Technician or Billy Bob or heck anybody can shoot down or reinforce?

We always hear about (and I agree) how its desirable that an ignition spark be bright visible BLUE versus a thin wimpy lookin YELLOW. Ima thinkin that's because its in part HEAT (Like a fire or a spark) that ignites the fuel air mixture and the BLUE spark is physically hotter in temperature then the YELLOW spark. If you think about it when you adjust a gas appliance its done so you get the nice BLUE flame (correct mix of air and fuel) versus the YELLOW flame (incomplete combustion, fuel to air ratio isn't right or something to do with all that???)

Soooooo is the BLUE spark physically hotter in temperature then the YELLOW spark??

If you notice if youre testing an ignition wire if the gap is close the spark is blue, but as you pull the wire further away it changes to a thin yellow. As I explained below the spark is of a fixed X energy which is Volts X Amps X Time so if voltage increases (due to wider gap) current and/or arc time duration decreases and so does the spark color!!!!!!!

Does BLUE represent higher physical temperature then then YELLOW????????????????????????? When I heat metal with my torch it eventually gets red then maybe towards white......

An ever curious John T
 

Because the testing at an air gap must be constant and measurable, many techs use spark testers that create approximately a 0.250” gap for older ignitions and a 0.500” spark gap for later, high-voltage ignitions. The color of the spark often has more to do with atmospheric contamination than it does with the quality of the spark. In some cases, a really “hot” spark is nearly invisible to the eye. Last, any spark generally appears weak when seen in direct sunlight, which can confuse the diagnosis.


I have only seen spark under pressure one time best I remember it was white...

I Wonder what color it is in a vacuum...

http://www.brakeandfrontend.com/Article/119712/tech_feature_ignition_coil_diagnostics.aspx
 
i throw a wrench in the bucket.. am not a Physicist, Mechanical and Thermodynamics Engineer. :)

power disipation is another factor inthat equation where you are chnging volts ( increaseing ), and decreasing amps.. etc.. and R is your spark gap.. or more correctly it's a dielectric that becomes ionized at a certian kv level.... . the V to jump the gap does as well, with current decreasing.

energy wise i think we are looking for something like .2j
 
in a true vacume you can have electron flow with high voltage and a pointed electrode.. just won't see an arc.

you can use a switch to trigger a spark in a vacume. not surprisingly this is called a triggered vacume spark gap switch.

small brite poitns of light can be seen usually from dust ont he electrodes or boiled off metalic atoms conducting the current.
 
Hello John T,

I'm back from weed wacking so you have a sparky question? Ignition coil spark color means nothing! The hottest spark is ultra-violet, which we can not see. Blue spark is cold in comparison to ultra-violet! Orange and yellow particles are sodium in the air ionizing in the high energy of the spark. There are no two combustion events with the same amount of power generated. Waaaayyyyy to many variables. Nice sparking with you again,

Guido.
a160710.jpg
 
John, yes, a blue spark is hotter than a yellow spark, or at the very least, it requires a hotter temperature to create a blue spark than a yellow spark. I think the original quantitative explanation came from Einstein in his photoelectric effect theory, for which he was awarded his Nobel Prize. As evidence, I would encourage you to google "why is blue light more energetic than red light", and pick some of the more credible sounding search results, like physics.org being more credible than Wikipedia.
 
John T. et al,
In astronomy, we classify stars by their color which by black body radiation rules directly relates to the temperature of the star's surface. In astronomy the temperatures are measured in Kelvins which uses the same degree as Celsius but starts 0 at absolute 0.

Class Temperature Color
O 30,000 - 60,000 K Blue stars
B 10,000 - 30,000 K Blue-white stars
A 7,500 - 10,000 K White stars
F 6,000 - 7,500 K Yellow-white stars
G 5,000 - 6,000 K Yellow stars (like the Sun)
K 3,500 - 5,000K Yellow-orange stars
M < 3,500 K Red stars

Notice that a blue star is hotter than a white star. The color that is emitted is directly related to the energy of the photons that are generated.
You can also use the colors that a prism produces as a guide to temperatures. Red is low energy to blue - high energy.
 
interesting.. so.. use the microwaves to speed up the initioal ionization of the atmosphere... hmm..
 

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