NationStates Jolt Archive

After a day of repeatedly blowing fuses (and getting a pretty reasonable shock into the bargain due to my own limitless stupidity) when trying to fix something, the question suddenly came to me - electricity flashes always seem to be blue, why is this?

Because it would look stupid in pink.

The color depends on the amount of energy it possesses. Red light has the least whereas blue (violet) light has the most.

It takes a relatively high level of energy to arc electricity through the air, even if only across a relatively small space. The color blue represents the higher-energy end of the visible portion of the electromagnetic spectrum (http://en.wikipedia.org/wiki/Image:Electromagnetic-Spectrum.png).

Thus an event involving high levels of energy tends to appear blue.

Note the color descriptions of lighting here. (http://en.wikipedia.org/wiki/Lightning#Properties_of_Lightning) "purplish," "blue-white," etc.

What F'n'G and TLO said. High energy=blue.

It takes a relatively high level of energy to arc electricity through the air, even if only across a relatively small space.

So where does the light come from? & why do lightning strikes not appear violet then?

Because it would look stupid in pink.

http://skydiary.com/gallery/chase2007/061107lightning2.jpg

:p

There's an even better pic in this month's BBC Focus magazine, where they fired a rocket into a cloud with a guide wire for the lightning... Several pink bolts followed it down.

http://skydiary.com/gallery/chase2007/061107lightning2.jpg

:p

See, I told you it looks stupid.

http://www.studip.uni-goettingen.de/pictures/smile/shock.gifhttp://www.studip.uni-goettingen.de/pictures/smile/sithlord.gif

Because pink lightning does look stupid.

So where does the light come from? & why do lightning strikes not appear violet then?

As evidenced by the pictures above, they do.

So where does the light come from?

In modern physics the photon is the elementary particle responsible for electromagnetic phenomena. It is the carrier of electromagnetic radiation of all wavelengths, including gamma rays, X-rays, ultraviolet light, visible light, infrared light, microwaves, and radio waves. (http://en.wikipedia.org/wiki/Photons)

In some way that I don't fully understand myself, the electrical spark event releases relatively high energy photons.

EDIT: Photons are emitted in many natural processes, e.g., when a charge is accelerated, during a molecular, atomic or nuclear transition to a lower energy level, or when a particle and its antiparticle are annihilated. Photons are absorbed in the time-reversed processes which correspond to those mentioned above: for example, in the production of particle–antiparticle pairs or in molecular, atomic or nuclear transitions to a higher energy level. (http://en.wikipedia.org/wiki/Photons#Physical_properties)

When something releases energy, some of that energy be photons.


... & why do lightning strikes not appear violet then?


Varying levels of energy in a particular lightning strike event. Or atmospheric conditions that alter the color as the light is traveling from the event to one's eyes. Or any number of other intervening conditions or events.

In some way that I don't fully understand myself, the electrical spark event releases relatively high energy photons.

From what I remember of doing this in school, a high-energy environment bumps electrons up to progressively higher energy levels. However, this is an unstable condition -- eventually, they have to fall back down. When this happens, the energy that initially pushed them up is released in the form of light.

It is NOT always blue.
It depends on the gas through which is it traveling.
A discharge though oxygen makes it blue.
A discharge though Neon makes it red-orange.
A discharge though Xenon makes it very bright white (HID headlights, strobe lights.)
A discharge though hydrogen makes it red-purple.

Freedom is right about the electrons - that's what makes the light. The molecule determines the color, though.

It is NOT always blue.
It depends on the gas through which is it traveling.
A discharge though oxygen makes it blue.
A discharge though Neon makes it red-orange.
A discharge though Xenon makes it very bright white (HID headlights, strobe lights.)
A discharge though hydrogen makes it red-purple.

Is there any reason for a fuse to have anything other than a standard air mix in it (for domestic purposes at least)?

Is there any reason for a fuse to have anything other than a standard air mix in it (for domestic purposes at least)?

Lightbulbs don't have standard air in them to stop the filament burning out so quickly... I suppose some fuses could have the same, but obviously the reason for fuses is...

Pretty sure light bulbs are a vacuum on the inside to keep the filament from burning. Any O2 gets in there and poof, no more filament.

Pretty sure light bulbs are a vacuum on the inside to keep the filament from burning.
Rather a mixture of inert gases so the pressure doesn't compress the bulb.
As to the OP, I'm never blue after the discharge but I can only sympathise with someone who has to use electricity for it.

my 'electric' discharges are usually white. And sticky.
I thought that was normal.
It is, innit?

Air has a pretty high resistance to electric current, i.e. it takes a lot of energy to move a given charge through some air. The energy is dispersed in the air thus heating it, just like a cucumber that becomes hot when you connect its ends to a high voltage source (sorry, couldn't think of a better example).

Now, when the air is rapidly heated by the energy dispersed due to the electrical resistance towards the charge running through the air (i.e. the current), electrons in the molecules are excited into higher energy levels. When you solve the Schrödinger equation* for a molecule (which you don't, since that is pretty damn hard), you'll find that they can only have certain energies in their bound state, and that the excited states are not stable. This means that the electrons will "fall back" into the original state, thus releasing the excitation energy which they got from the heat. This energy is released as a photon with that energy.

As mentioned above, only certain energies are allowed for the electron, and thus the energy differences between the ground state and the excited states are also pretty much fixed. The result is that the energy, and thus the colour of the photon, is fixed.

Air is mainly composed of dinitrogen (N2) and dioxygen (O2), and it is the energy differences between electron states in these molecules that determine the colours of electric discharges is the atmosphere.

I realize that the above is rather technical, and I'd be happy to elaborate should anyone request it.

*From quantum mechanics