What is Green: Definition and 306 Discussions

Green is the color between blue and yellow on the visible spectrum. It is evoked by light which has a dominant wavelength of roughly 495–570 nm. In subtractive color systems, used in painting and color printing, it is created by a combination of yellow and cyan; in the RGB color model, used on television and computer screens, it is one of the additive primary colors, along with red and blue, which are mixed in different combinations to create all other colors. By far the largest contributor to green in nature is chlorophyll, the chemical by which plants photosynthesize and convert sunlight into chemical energy. Many creatures have adapted to their green environments by taking on a green hue themselves as camouflage. Several minerals have a green color, including the emerald, which is colored green by its chromium content.
During post-classical and early modern Europe, green was the color commonly associated with wealth, merchants, bankers and the gentry, while red was reserved for the nobility. For this reason, the costume of the Mona Lisa by Leonardo da Vinci and the benches in the British House of Commons are green while those in the House of Lords are red. It also has a long historical tradition as the color of Ireland and of Gaelic culture. It is the historic color of Islam, representing the lush vegetation of Paradise. It was the color of the banner of Muhammad, and is found in the flags of nearly all Islamic countries.In surveys made in American, European, and Islamic countries, green is the color most commonly associated with nature, life, health, youth, spring, hope, and envy. In the European Union and the United States, green is also sometimes associated with toxicity and poor health, but in China and most of Asia, its associations are very positive, as the symbol of fertility and happiness. Because of its association with nature, it is the color of the environmental movement. Political groups advocating environmental protection and social justice describe themselves as part of the Green movement, some naming themselves Green parties. This has led to similar campaigns in advertising, as companies have sold green, or environmentally friendly, products. Green is also the traditional color of safety and permission; a green light means go ahead, a green card permits permanent residence in the United States.

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  1. R

    Formation of Silver Nanoparticles from Green Tea Reducing Equivalents

    Hi everyone, This is my first thread so I'll try to be as clear as possible and try to follow the rules. My job is to synthesize silver nanoparticles, characterize them (TEM, DLS, EDAX, Z-POT), and then pass then on to the toxicologists. This is my thesis work to graduate. A new thing I have...
  2. P

    Question about Green, Schwarz, Witten Appendix 4.A on N=1SYM

    It's really just a dumb question about spinors. The book says that for N=1 SYM, in 3 or 4D we use Majorana spinors. In 6D we use Weyl spinors. And in 10D we use Majorana-Weyl spinors, so that the number of fermionic states matches D-2. My questions is, in 4D, Weyl spinors (chiral spinors)...
  3. B

    Which line is stonger? orange, green or blue?

    Homework Statement hey, i just wanted to know which line is stronger: orange, green or blue(i mean light which one has a stronger line? ) how would you know it? thanks in advance BA Homework Equations N/a The Attempt at a Solution I'm not sure how to approach it do...
  4. B

    Which line is stonger? orange, green or blue?

    hey, i just wanted to know which line is stronger: orange, green or blue(i mean light which one has a stronger line? ) how would you know it?thanks in advance BA pls delete this post I am going to post in homework help. sorryi posted it the wrong section:
  5. M

    Green Function for Second Order Differential Equation with Initial Value Problem

    Homework Statement need to find the green function for d^2X / dt^2 + 2 dX/dt +(1+k^2)X= f(t) with IV X(0)=dX/dt (=0) = 0 Homework Equations eq. attached The Attempt at a Solution attached whenever I try to solve the homogonous part, I get 0 due to the IV. guessing my...
  6. KrisOhn

    TD Go Green Challenge - Save the Earth & Preserve Astronomy

    This isn't even for the campus where I go to school, but as an amateur astronomer, I feel that this message should be spread everywhere. http://www.tdgogreenchallenge.com/video/p/1/playid/149/id/149/ Light pollution is something more than a nuisance to astronomers, it is also something that is...
  7. A

    NIH fellowship eligibility on partial green card approval

    Hi, This may be very specific - NIH fellowships generally require US citizenship or permanent residency. I am wondering if an approved I-140 is good enough to get through the door. Does anyone here know about this? Thanks.
  8. K

    Identifying Green Mold on Cheese: A Microscopic Approach

    What is the dark green mold on old white cheese called? is that penicillin?
  9. E

    Violet light produced from green He-Ne laser?

    I was setting up a 2.0 mW, unpolarized 543 nm (green) He-Ne laser today when I discovered something odd. I was using an iris diaphragm (like these: http://www.thorlabs.com/NewGroupPage9.cfm?ObjectGroup_ID=206) to align the beam parallel to the laser table. I found that if I placed a white...
  10. mrspeedybob

    Understanding the Science Behind Blue + Yellow = Green Perception

    We perceive blue light mixed with yellow light to be equivalent to green light. Does this have more to due with the way the wavelengths interact or some other physical phenomena or is it a biological phenomena
  11. Simfish

    Making bacteria express green fluorescent protein - could it decrease fitness?

    Since it obviously takes energy and extra amino acids to express the green fluorescent protein, so it's possible that bacteria expressing GFP might have slightly lower fitness (on average) than bacteria that aren't expressing GFP. I'm sure the effect is negligible in most cases. But maybe...
  12. K

    About the n-point Green functions in position-space

    When we want to calculate the n-point function in the position space, it's always very difficult. For example, when we're calculate the 3-point function of \phi^3 theory in position space, we would get an integral \int d^4 z \frac{1}{|z-x_1|^2|z-x_2|^2|z-x_3|^2} It seems hard to integrate it...
  13. K

    Where Does the Green Go at Twilight?

    Why is no green color on the sky at twilight??
  14. D

    Medical Opponent process theory: why do I see green after looking at white?

    This morning, I was lying on my bed, looking at the bright morning light coming in through the window. The blinds (which are white) were at least half shut, so much of the light was filtered through them. I then stared up at the ceiling, and saw a nebulous patch of green. I shut my eyes, and...
  15. G

    Calculating how far a golf ball will travel on a green before it comes to rest?

    I have been trying to calculate how far a golf ball will travel on a level green given the following variables: The initial velocity of the ball is 1.49 m/s The coefficient of friction between the ball and the green is .0409 The mass of the ball is 0.046kg The diameter of the ball is 42.6mm...
  16. D

    Are Green Lasers Illegal in Canada?

    Hi, I have this pretty cool 5mW green laser and I'm wondering if it is legal as long as I don't try to blind drivers and pilots.
  17. P

    How Sustainable is Our Consumer Culture?

    On a recent reality show a young couple wanted to purchase a second home in the pacific northwest as a getaway. They claimed to be strong environmentalists and wanted a 'green' home. So what is wrong with this picture? I mean they can afford it so why not? Well there's nothing wrong with...
  18. W

    Two dimensional green function

    In studying the scattering problem, one should know green function in free space. while in two dimension, green function is the hankel function, seen in the attached file. bu i got confused in the second equation in the attached file. could anyone give me some details about this relationship? it...
  19. L

    Television etc and green, red, blue

    The antenna cable tranfers only the 3 frequencies of green, red and blue, yes or no?
  20. S

    Exploring the Resolving Power of Green Bank's 300-ft Telescope

    Question: Before it collapsed in 1989, Green Bank's 300-foot diameter telescope mapped the sky in H I. What was its resolving power? I believe the formula you would use is resolving power = (wavelength in microns) / (diameter in meters) So the diameter in meters would be about 91.44 m, but...
  21. F

    Tracing the Light Path of a Green Laser Pointer

    How is it possible to see the light path of a green laser pointer?
  22. S

    Are There Green Stars? Exploring Unusual Astronomic Colors

    I was out in my backyard performing some astronomic observations for azimuth and latitude and was treated to a few of the recent meteors. I have seen a few different colored ones and it got me to wondering. I have heard of red, blue, white and other colored stars, but don't ever remember...
  23. Pythagorean

    Can Green Peas Really Grow Inside the Human Body?

    Well, at least this one is: http://www.myfoxphoenix.com/dpps/news/offbeat/pea-of-life-grows-in-ny-man's-lung-dpgonc-km-20100810_9112207
  24. M

    Speed inorder to shift green light to blue light?

    Hypothetically if your in a jet or spaceship & are shining a green laser pen out the window how fast must you travel to cause the green light (570 nm) to change into low energy blue light (475 nm)
  25. S

    News Saudi Arabia giving green light to Israel?

    Apparently this is a possibility: http://www.timesonline.co.uk/tol/news/world/middle_east/article7148555.ece The "stone age" monarchy terrified of the "stone age" theocracy! The real unknown is whether Obama would shoot down an IAF mission over Iraq en route to Iran. George Washington was...
  26. P

    Green function for KG equation

    There exists very simple formula for Green function for wave equation: G(t,x,t',x') = \delta (t-t'\pm \frac{|x-x'|}{c})/|x-x'| . I wonder whether there exist similar formula for Green function for Klein-Gordon equation (with mass >0) for any boundary condition.
  27. K

    What is the Greenhouse Effect and How Does it Impact Our Planet?

    I don't understand the green house effect. According to wikipedia, the green house effect is the result of non-directional re-emission of thermal radiation after being reflected from the ground from water vapor, methane, carbon dioxide etc., but shouldn't it cancel itself out? Shouldn't just as...
  28. K

    Proof of Green Theorem in Apostol's Analysis

    Hello guys, I got a question about one point in the Green's theorem proof that appears in Apostol's Mathematical Analysis, first edition, Ed. Addison Wesley. More exactly, in the theorem 10-42, immediately previous (and essential) to Green's (p. 287-289). Please, if this is too involved or...
  29. R

    =Which Color is Brightest: Red, Green, or Blue Light?

    which colour is brightest (red monochromatic light, green monochromatic light and blue monochromatic light )? and which light will give highest radiant flux? why? Thank you
  30. I

    Special Relativity Problem -- Speeding through a red light to make it look green

    By now i must be driving you guys crazy with my relativity questions , but this is my last one! i swear! =] Homework Statement A noted physicist was stopped by police for traveling through a red traffic light. The physicist argued that to because he was traveling fast, the colour of the...
  31. Ivan Seeking

    Fungus Discovered in Rainforest May Offer New Source of Green Energy

    Competition for algae? http://www.physorg.com/news144958975.html
  32. S

    GEM*STAR: Future of Green Energy Reactors?

    So the latest thing I've seen being talked about is GEM*STAR (Green Energy Multiplier*Subcritical Technology for Alternative Reactors) http://nextbigfuture.com/2010/04/molten-salt-based-accelerator-driven.html They claim they are leveraging the ever improving efficiencies in producing...
  33. L

    Question about Brian green book THE FABRIC OF THE COSMOS

    On page 56 last paragraph Brian give example of a train paradox where two person have clock and there is two observer on on the train the other outside. They agree to set there clock at 12:00 when they see the light open witch is placed between them. From there perspective each clock will be...
  34. W

    Why the green function is useful?

    as a student in physics, i cannot see the usefulness of green function to me, the definition of a green function is ugly and singular we have to deal with functions that are not smooth, e.g., the derivative is not continuous at some point. How these functions can be useful in math and...
  35. J

    How can a MechE look good for green engineering?

    im currently a freshman majoring in ME, and in the future want to work with (dont know specifically what yet) renewable energy, designing more efficient energy-harvesting systems, etc. but, i know there are tons of kids in my generation aspiring to do the same. is there a specific...
  36. W

    What is the Green function solution for a damped harmonic oscillator?

    I was reading up on Classical Mechanics and the general method for solving for an undamped harmonic oscillator was given as \frac{d^{2}q}{dt^{2}} + \omega^{2}q = F(t) was solved using the Green function, G, to the equation \frac{d^{2}G}{dt^{2}} + \omega^{2}q = \delta(t-t') and then...
  37. I

    Help How to get green function of Bessel's differential equation?

    In my project, we enconter such kind of bessel's differential equation with stochastic source, like \Phi''+\frac{1+2\nu}{\tau}\Phi'+k^2\Phi=\lambda\psi(\tau) where we use prime to denote the derivative with \tau, \nu and \lambda are real constant parameter. how to get the green...
  38. M

    Why Do Computer Chips Come in Different Colors?

    Why do almost all computer chips have green color? Like the RAM, microprocessor, motherboard are mostly of green color. Does this green color have any relation with the fact that chips are made of silicon i.e. are they green due to the presence of silicon? I've also seen brownish color...
  39. P

    Fourier Transform of a productof Green functions

    Guys, how do u get the Fourier transform of a product of Greens Functions?I have to get Fourier transform of: G_{el}(k+q,\tau-\tau1)*G_{el}(k,\tau1) where \tau and \tau1 are two different times (\tau>\tau1) and q is phonon momentum and k is electron momentum... Thanks
  40. G

    Unlocking Limitless Green Energy: Harnessing Earth's Rotational Kinetic Energy

    The Earth rotates in inertial space. The amount of rotational kinetic energy is enormous ... millions of mankind's annual consumption. Is there any kind of apparatus, perhaps one based on gyros, that could tap into this energy?
  41. M

    Thermal green function and complex integration

    green function and complex integration Homework Statement By reading this paper http://arxiv.org/pdf/hep-ph/0610391v4 I cannot proof the following relation on page 9 equation (23) , by a suitable choice of a contour in the complex omega plane: \int\frac{d^3 p}{(2\pi)^2}...
  42. B

    Finding Green Light Wavelengths for Dissertation

    Hi sorry if this is very basic, I am an animal final year student and have come across a problem for my dissertation. I am looking at wavelength of light. Now the question, is a green bulb purely giving off green light, ie if it more blue green is it giving of predonimantly light of around 500...
  43. S

    Expansion of free space Green function in Bessel function

    Homework Statement In Jackson 3.16 we have to prove the expansion \frac{1}{\left{|}\vec{x}-\vec{x'}\right{|}}=\sum_{m=-\infty}^{\infty}\int_{0}^{\infty}dke^{im(\phi-\phi')}J_m(k\rho)J_m(k\rho')e^{-k(z_{>}-z_{<})} Homework Equations The Attempt at a Solution I tried to use the...
  44. R

    Are there green, purple and pink stars?

    They don't look that way in the sky, but are there stars that look that way up close?
  45. F

    Time variant Green function

    Hello forum, in the case we are in the time domain t, the Green function is a function of time. In the translation variant case, how do we express and separate the regular time variability of the Green function from the the time variability of its functional form? 1) What is the best...
  46. matthyaouw

    VOTE PF PHOTO CONTEST - Green Living

    1.Andre 2.ZapperZ 3.Borek 4.Marzena 5.Edward http://img529.imageshack.us/img529/5134/a0099bw8.jpg Contest Thread
  47. matthyaouw

    PF PHOTO CONTEST - Green living (sept 19-26)

    Green living Interpret as you will. Contest Rules: 1. Any digital photo or digitally-scanned photo relevant to the theme will be accepted within the contest period. In case there's a gray area, or you're not sure if the picture is suitable, check with me first. 2. Please resize your...
  48. P

    Where Can I Find Problems with Tiablikov Green Functions?

    Where can I find problems with Tiablikov Green functions: G(x,x';t,t')=\theta(t-t')<[\hat{\mathal{A}}(x,t),\hat{\mathal{B}}(x',t')]> Thanks!
  49. Q

    Sitting my lcd on top of a green mat

    One of those green one inch thick garden knee pads is what i am talking about. If I sit my lcd monitor on one of these mats do you think it would be more stable? If you put a hard lcd base on a hardwood table I imagine it will not sit perfectly because of imperfections in the perfect...
  50. V

    Exploring the Preference for Green over Red: A Scientific Inquiry

    is green better than red? Over the past couple of days, i seem to have noticed that sometimes, people like green better than red. I have been thinking about it and felt that it should be brought to discussion as to why green seems to be better. I know it sounds rather strange, but when you...
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