Dave's ESL Cafe's Student Discussion Forums

[admiral]

Just wait until I fully understand him and wait for the explanation.
And try to talk to the point.
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If I say "I love you" to someone, then I also have to say "I love inside you everyone else. I love the whole world because of you. I also love myself inside you"

[stellara]

hmm.. I think, too, that you argumentation itself is right, but the condition is not correct. but I have to think about your and my argumentation again to give a real statement.. wait until next week, maybe then I'll have more time. ok?
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Don't cry because it's over - smile because it happened!

MOKEY ROCKS!!!

[asterix]

Admiral, there none so deaf as he who does not want to hear.

[admiral]

hey, asterix
If you can't contribute to this topic, you can also be quiet.
If you know everything, then say everything.
If you don't know anything, then don't say anything.
_________________
If I say "I love you" to someone, then I also have to say "I love inside you everyone else. I love the whole world because of you. I also love myself inside you"

[stellara]

hello again
so, after we had this issue in ohysics today, i want to add a few things and i hope these misunderstandings will get fixed now

in coloured water there are very tiny colour pigments. these are so-called dye molecules. They are the cause why the water is coloured (understandable if you take water colours as an example).
all molecules are made up of atoms, which contain the atom nucleus (protons and neutrons) and the atom sheath with the electrons. the electrons surround the nucleus in an electron configuration or else said in discrete orbits or shells (this is only a model, we don't know for sure yet if this is right or not).

these orbits have different energies. in the lowest which is also the nearest to the nucleus (called K-orbit) the electrons has the least energy. in the next (L-) orbit it gains more energy, and namely the energy difference between the K- and the L-shell, and so on. if the electron gets more energy (from outside) it's induced (right word?!) to the next higher shell. this is called a quantum leap, by the way

so, in this higher energy level the atom is in a labile state, so it leaps back to it's original state, the K-shell. in this process a so-called photon is emitted, because if the K-shell is a lower energy level, energy is emitted (--> a photon is energy). a photon is also light (the visibility depends on its wave length).

soo, now we understood the electron configuration, i hope
ok, what does this have to do with coloured water's characteristics?!

these dye particles which are in coloured water are made up of atoms. if white light (which is energy and contains all colours) comes on the coloured water, it also hits the dye molecules and induces the electron. Because of the discrete energy levels it can absorb just exactly this energy which makes the difference between the K- and the L-shell. only a certain colour of the light contains this certain amount of energy (E = h*c/lamda, lamda is wavelength/colour). let's say this colour which can be absorbed is red light. so, but the electron doesn't "like" the labile state in a higher energy level, so it leaps back to the lowest shell and thereby a photon is emitted, which has exactly the same wave length of the light which was absorbed, so to say red.

because the water is irradiated with white light from one side and the atom emits red photons in every direction, the red light line from the white light is extinguished. so we see just the colours of the white light which remain when the red light isn't there anymore, they are the complementary colour of red -> which is green. so we see the water as green.

ooh, it's so complicated but I hope it's at least a bit understandable..
greets
_________________
Don't cry because it's over - smile because it happened!

MOKEY ROCKS!!!

[admiral]

thanks
_________________
If I say "I love you" to someone, then I also have to say "I love inside you everyone else. I love the whole world because of you. I also love myself inside you"

[pugachevV]

Seems to me, Herr Admiral that asterix has contributed quite a lot to this forum.
I know it is difficult to admit you are wrong, but when you grow up it will become easier.
You may even become enlightened.
Sto Lyet.

[admiral]

But that somebody has stayed here a long time doesn't mean that his opinion is always right, you know?
_________________
If I say "I love you" to someone, then I also have to say "I love inside you everyone else. I love the whole world because of you. I also love myself inside you"

[admiral]

Ok, I try it again. But not to let you accept my idea, because I gave it up. I only say my idea, and if you don't have any hatred, you could sit down and read.
Our question is only: Does red material reflect or absorb red light?

In this case, we already know that every mix of material or watercolor follows this rule.

We also know that white light contains of all spectrum of lights. And the light shining on the material always consist of all spectrums of light.

What we know is that darker things absorb more energy. Take an example at solar panels They are made of dark color, because dark color absorb more energy.

So listen, now we have an experiment of three colors: purple, yellow, and the product if you mix purple and yellow materials with each other, that is red.

So, if you have a yellow material, and if it would absorb the yellow light of the white light, which consists of the green light and the red light, and then there would be dark blue light left. Dark blue light is colder, because it consists of a small amount of all spectrums of light.

So, if you have a red material, which is a result if you add yellow and purple things together, and if it would absorb both the yellow and the purple light (I recommend you looking at) , then it will only reflect the bright blue light. (Yellow=green+red) (Purple=red+darkblue) Bright blue light is warmer, because it consists of green light and darkblue light.

So we have: yellow material reflect dark blue light, red material reflect bright blue light.
Bright blue light have more energy than dark blue light.

Find the error in this explanation and disprove it with your argumentation. And then I will believe you.
_________________
If I say "I love you" to someone, then I also have to say "I love inside you everyone else. I love the whole world because of you. I also love myself inside you"

[pugachevV]

Admiral, tovarisch, You wrote:

[admiral]

[obelix]

I remember being confused by this at school, but I think the tovarisch parusskiy is right is right.

[stellara]

yeah, that's difficult to understand.
take a look at this website:
http://www.physik.uni-muenchen.de/leifiphysik/web_ph12/versuche/10absorblin/absorpt.htm
http://www.physik.uni-muenchen.de/leifiphysik/web_ph12/versuche/10absorblin/absorptionstunnel.htm

this experiment is with an certain material, sodium, like you have it in common salt (sodium chloride). if you put some of this common salt into a very hot flame, this flame will glow yellow/orange. this is because the heat of the flame can induce the sodium-electrons and during their leap back to their normal level they emit photons with a wavelength which appear yellow/orange to us. these photons are emitted in every direction.
so, this is without any external irradiation. you have just the flame and the salt.

now you take common white light, from a light bulb maybe. if you put it in front of the flame, the flame is irradiated with white light by front. now you'll repeat the experiment with the salt and the flame. the flame will still glow orange, and the sodium atoms will still emit the photons. but because they emit them in every direction they also emit them in direction to the white light bulb, which also has exactly this wave length (white light has every colour). so there are two electromagnetic waves with exactly the same length but directly opposed --> they extinguish each other!

ok?

and because you can't see this absorption very good, you can make another experiment.
take a sodium discharge lamp instead of an ordinary bulb. it will irradiate only these wave length which the emitted photons have, too.
if you now put some salt into the flame which is irradiated by the sodium discharge lamp by front, you'll see a dark shadow on the wall behind the flame. that's the prove.

greets

ps: I don't think this is about being right or wrong, it's just about understanding. and this is such a difficult matter that's okay not to understand it by the first time. and why shouldn't he ask for further info? it's the only way to become clever thanks for posting anyway!
_________________
Don't cry because it's over - smile because it happened!

MOKEY ROCKS!!!

[pugachevV]

Admiral, tovarisch... we may have been there two weeks ago but you still don't get it, but keep going off chasing red herrings. (Which absorb all light but red).
All I'm trying to do is help you to understand.
The Wall is already down...Relax.

[KHF]

Here's an easier experiment to try:

Go to a dark room, turn off all the lights, close the door, shine some red light on a piece of red paper and observe.

If "being red" means absorbing the red spectrum of light, you will hardly be able to see anything at all since right now the only light provided is red.

Experience however, told us that this is not what happens, thus proving that red objects indeed reflect (not absorb) red light.

You can also try shining blue light on a red object. This time you should see black as expected.