What causes colours?

[Michael F. D.]

Originally posted by Radical Edward

I am not talking about more and more accurate theories. and besides, none of them contradict current theories, they are just a better version which can be approximated e.g. Newton is a good approximation of Einstein. throwing into the fray things like SuperString theory (the only one of those theories you name that I recognise) does not at all alter the fact that you are still entirely wrong, and colour is caused by the electrons, and not nuclear forces. All the examples you have given so far can be explained with current theories.

This is just your faith in the might of existing theory. I am asking you to show how this does works, third time already . Give the reference (link) where there is a description of these phenomenas, please. Prior to this a moment, I'll consider your statements as not motivated.

[JaKiri]

Well, I'm pretty sure that any future theory on the origin of colour will be based around electron transitions; just because general relativity produces slightly different results to newtonian mechanics doesn't mean that gravity is caused by, say, flavour instead of mass.

 

And http://www.google.com for maxwell colour, or just get a sodding physics textbook.

[Radical Edward]

I already have. I told you to read Born and Wolf: Principles of Optics. It's a pretty monumental tome that will tell you everything you need to know about this sort of thing. It doesn't go into atomistic theories, but it does give references to these if you really want them. You might also consider learning a bit of maths too. I suggest partial differentiation and vector analysis.

[JaKiri]

Join me in my quest to make PDE's harder. The process is far too simple as things stand.

[fafalone]

The root of pseudoscience is ignorance. The reason we strongly accept current theories is because their derivation is extensive. Some guy didn't just think up our theories, a bunch of people spent a whole lot of time exhaustively working through mathematics and experimental data to arrive at a conclusion. Anyone who has had formal education in physics appreciates this process, hence why the only theories come from people with no education who blame our education for not accepting their models that lack the entire lengthy process of an accepted theory.

[Michael F. D.]

Originally posted by fafalone

The root of pseudoscience is ignorance. The reason we strongly accept current theories is because their derivation is extensive. Some guy didn't just think up our theories, a bunch of people spent a whole lot of time exhaustively working through mathematics and experimental data to arrive at a conclusion. Anyone who has had formal education in physics appreciates this process, hence why the only theories come from people with no education who blame our education for not accepting their models that lack the entire lengthy process of an accepted theory.

Are you sure, that it is given to see the reality for people ?

Can be so all "objective observations" are an illusion of our perception. I do not derogate the role of science and its achievements. I want to pay attention to some questions which much logical to consider in inversion. This is situation, about which people speaks:

- do not faith your eyes.

[Radical Edward]

but you are criticising something that you barely show any evidence of even understanding in the first place.

[fafalone]

Things like spectrometers are NOT subjective.

[NSX]

What about colour on paper?

The e-'s are relatively stable, as its a solid...so they don't jump orbits & produce colour, or do they?

[greg1917]

no, light from a source will hit the paper and depending on what it hits, certain parts of the spectrum will be absorbed. for exampe purple ink appears purple because green light is absorbed, meaning the resulting red and blue parts of the spectrum combine to give purple.

 

the same thing happens when you shine light through a sample, you'll get an absorption spectra. in this case the colour absorbed corresponds to the energy difference between the electron energy levels, as before E = hf

[NSX]

Originally posted by greg1917

no, light from a source will hit the paper and depending on what it hits, certain parts of the spectrum will be absorbed. for exampe purple ink appears purple because green light is absorbed, meaning the resulting red and blue parts of the spectrum combine to give purple.

 

So...when we print red ink onto a piece of paper w/ a printer, it shoots out atoms that absorb only the green & blue part of the spectrum? SO that we see red?

[greg1917]

Yes, the red ink the printer jets onto the page will absorb light in the blue and green range.

 

Most colour we use in dyes are to do with transition metal complexes. A transition metal is, by definition, an element which has an incomplete D subshell in at least one of its ions. a complex ion is a central metal ion surrounded by ligands (negative ions or polar molecules).

 

In an isolated transition metal, all 5 D orbitals are degenerate. however, when ligands approach this ion the orbitals are split. the difference in energy between these orbitals is known as the crystal field strength. this means if radiation of the correct energy is absorbed there will be a d > d transition. in some cases the crystal field strength will correspond to light in the visible region (as E = hf) so this particular transition metal complex will appear coloured.

 

If that went over your head dont worry, ignore the last two paragraphs.

[NSX]

Originally posted by greg1917

Yes, the red ink the printer jets onto the page will absorb light in the blue and green range.

 

Most colour we use in dyes are to do with transition metal complexes. A transition metal is, by definition, an element which has an incomplete D subshell in at least one of its ions. a complex ion is a central metal ion surrounded by ligands (negative ions or polar molecules).

 

In an isolated transition metal, all 5 D orbitals are degenerate. however, when ligands approach this ion the orbitals are split. the difference in energy between these orbitals is known as the crystal field strength. this means if radiation of the correct energy is absorbed there will be a d > d transition. in some cases the crystal field strength will correspond to light in the visible region (as E = hf) so this particular transition metal complex will appear coloured.

 

If that went over your head dont worry, ignore the last two paragraphs.

 

Ewww...Chemistry!!!!!

hahaa;

It's okay, I had to learn it from a textbook; principal quantum numbers, secondary quantum numbers, spin quantum numbers, & 1 more?

 

ugh; I hate chemistry.....probably b/c my teacher seemed like she was constantly pulling stuff out of her arse:rolleyes:

[Radical Edward]

Originally posted by NSX

ugh; I hate chemistry.....probably b/c my teacher seemed like she was constantly pulling stuff out of her arse:rolleyes:

 

this is why you should do physics rather than chemistry

 

The physics behind molecular emission and absorption is alot more complicated than sigle atoms. not only do you have the atomic spectra to consider, but then there are all the perturbations due to molecular vibrations, of which there are many types. Also large molecules tend to have a very broad IR emission.. so all the energy they absorb is reemitted in the IR, just in case you wonder where it goes.

[greg1917]

I was giving an example of one type of method by which colour is observed. Obviously there are others and molecular vibrations are indeed complicated and come in many guises (symmetric stretching, twisting deformation, scissor bend...) but a sound understanding of chemistry in this area is quite important to appreciate the underlying theory.

 

the principle quantum number, n, is the main energy level. 1,2,3, etc.

 

the second quantum number, L, determines the shape of the sub-shell and is labbeled s,p,d,f. they can have values from zero to (n-1).

 

thus if n=4 then L could equal

0 (s sub shell)

1 (p sub shell)

2 (d sub shell)

3 (f sub shell)

 

The third quantum number, m, relates to the orientation in space of the orbital. it is dependant on L because m can be any whole number between -L and +L.

 

thus if L=2 (a d orbital) then m could be -2, -1, 0, +1, +2.

 

the orientations of the s orbiatls are spherical and increase with n. the three p orbitals are dumb bell shaped, lying along each axis also increasing with n. the 5 d orbitals are a little more complex, and as for the seven f orbitals, theyre more complex still.

 

The fourth quantum number,s, is so called because it relates to spin. it is either +1/2 or -1/2.

[Radical Edward]

that all looks like physics to me, not chemistry.

[greg1917]

Whether its physics or chemistry is irrelevant, its talking about an important chemical concept which is the behaviour, notation, probability and nature of electron orbitals. Why is it necessary to label things as chemsitry, physics, physical chemistry or chemical physics? Its all science, arguing over whose type is better is like 8 year olds arguing over whose games console is better.

[NSX]

Well, to me; Physics seems alot more organised than Chemistry, maybe b/c its been around for a while. While chemistry is still a bit iffy...

 

ie. For every 10 questions I ask in Chem to my teacher, the answer to 9 of them is Well, that's just the way it is. WHile in Physics, there's a logical reply.

[JaKiri]

The trouble with chemistry is that quite a lot of it (below degree level at least) is fluffing along with 'simple' models.

 

The trouble is it's all based on the Schrodinger Wave Equation, which isn't very nice at any level.

[NSX]

Originally posted by MrL_JaKiri

The trouble is it's all based on the Schrodinger Wave Equation, which isn't very nice at any level.

 

What's the formula?

I'll try asking my chem teacher about it...hahaa

[greg1917]

First of all in what way is chemistry more 'organised' than physics? Do the text books not fit on the shelf or something? Secondly the reason your teacher gives you more questions is probably because he/she doesnt know. Ive just finished an advanced higher in both subjects and neither is more 'organised' and neither has been around for very long. Faraday discovered benzene as well as his work on electricity. You could go back to alchemy, which dates hundreds of years, but thats more a crackpot science at heart.

[JaKiri]

Originally posted by NSX

What's the formula?

I'll try asking my chem teacher about it...hahaa

 

Don't ask.

 

Just don't ask.

[NSX]

Originally posted by MrL_JaKiri

Don't ask.

 

Just don't ask.

 

lol

She'll be like:

[Michael F. D.]

Originally posted by greg1917

Yes, the red ink the printer jets onto the page will absorb light in the blue and green range.

 

Most colour we use in dyes are to do with transition metal complexes. A transition metal is, by definition, an element which has an incomplete D subshell in at least one of its ions. a complex ion is a central metal ion surrounded by ligands (negative ions or polar molecules).

 

In an isolated transition metal, all 5 D orbitals are degenerate. however, when ligands approach this ion the orbitals are split. the difference in energy between these orbitals is known as the crystal field strength. this means if radiation of the correct energy is absorbed there will be a d > d transition. in some cases the crystal field strength will correspond to light in the visible region (as E = hf) so this particular transition metal complex will appear coloured.

 

If that went over your head dont worry, ignore the last two paragraphs.

Explain the result of following experiment, please.

If take the sheet of the white paper and drip on it a water, then we'll see the gray spot. We note that a water is transparent.

[greg1917]

I dont know, what does that have to do with anything you quoted me on? Does a constituent of the paper go into solution?