Colour Definition and 178 Threads

I noticed this when I was holding a piece of paper in front of my blue led computer light. when a object (finger) is placed in front of the paper wiht the blue led light shining on it the shadow of the object is yellow. why? I tried to explain it as yellow is the complementary colour of blue...

i have read that light is made up of photons :smile: how does similar photons can produce lights of different colours(pardon me if this appears a silly question to u:redface:

Hi, all. A weird question popped into my head this morning, after I swatted W across the snout because I dreamed that a wasp was bothering me. I know that it wasn't really a wasp because it was brilliant crimson. That reminded me of the olden days question of whether or not people dream in...

suppose there is a cube and we can colour the cube's faces with only two colours ..i.e. black and white ,,how many different patterns are possible...

I'm assuming this would be a good spot to ask this. I'm looking for a solution that is clear initially but will change a very dark colour and probably stain when exposed to either direct sunlight (at least take 5 or 10 minutes) or rainwater, or cold temperatures (about minus 5C to minus 15C)...

What is colour of the bear that has fallen from a 20 meter high mountain in 2 seconds. : :smile: Coments,suggestions and aswers are kindly welcomed :: :confused:

It may be a strange question, Is there a dominant colour in our universe? ignoring black and white. I have looked but can not find any thing.

I have been pondering about the nature of colour and its philosophical status as either an irreducible, objective property of an object or rather as a derived quality, dependent on the perceiver. Basically, to put it in Lockeian terms, the question is whether colour is a 'primary' or a...

I want a yes or no answer and a short explanation. o:)

I saw this binary with me friend's 10-inch. The secondary looked so blue I could not believe my eyes! Has anyone hear noticed the deep colour of this lovely double star? Eridanus1

Hi there, Could anybody please explain how electron-positron annihilation supports the conjecture that 3 colour states exist for quarks? Plus in the Baryon 1/2 octet and 3/2 decuplet, what would be the corresponding set of states if colour did not exist, such that quarks of the same...

Einstein field equation gravitational potential: \nabla^2 \phi = 4 \pi G \left( \rho + \frac{3P}{c^2} \right) General Relativity gravitational pressure: P_e = \frac{c^2}{3} \left( \frac{\nabla^2 \phi}{4 \pi G} - \rho \right) Classical Yukawa Pressure: P_y = f^2 \frac{e^{-...

I have read some 'popular' physics and I get the impression that Electrostatic Force is caused due to transfer of virtual photons. Do these have a particular energy for a particular charge? Then they should have a particular frequency . Then if we place the charges in mediums with...

If neutrons stay intact and get closer together than 10^-15 metres in a neutron star, would the exchange of mesons between neutrons stop and be replaced by the exchange of gluons, and would the gluons cause an attractive or repulsive force between neutrons? A repulsive force could stop the...

Is heat always the factor that determines the colour of a flame? Is there a way of approximating the variations in colour that would occur within flames from a wood fire?

What determines the colour? Frequency or wavelenght?

Individual quarks change colour as time passes. Since colour is physically tied to electric charge - colour and electric charge travel through space together - why doesn't a change in colour change the electric charge of the quark somehow? And when a muon loses mass and becomes an electron...

Think of a proton being orbited by a single electron.Gluons in the proton have energy and so must curve space-time and so affect the passage of electric force-mediating photons - traveling from the proton to the electron - through it.So the electric force and colour force interact.This means...

is it possible that everybody sees different colours but we don't realize because people are taught what colour is what according to things in the world? example, everyone is taught the sky is blue, but what if everybody sees the sky as a different colour, no matter what they see they would...

can the human mind invent a new primary colour that is only in their minds, but they can actually picture it and envisage it. the mind's concept of colour must be based purely on what we have seen. heres another question, there is a lot we don't know about the universe, imagine if we...

What are your favourite: 1.Food :-p 2.Colour :surprise: 3.Smell 4.Clothe :blush: 5.Weather :cool: 6.Program :smile: 7.Book :bugeye: 8.Forum :wink: 9.Misc [Add your own] :rolleyes: :zzz: :redface: :shy: :-p :confused...

I am required to ask questions as part of my physics assignment at school. I am in Yr 11 physics btw. If some people can please answer these that would be great. Before anyone says i should know some of these or that i could find out by surfing the internet, i know that i canm but none the less...

if there's two identical object of the same mass and same composition but is of two different colours, would one weigh heavier than the other?? assuming that the coating of paint that gives the object its colour is of the same density for each colour and that same volume of each colour is used...

Colour and heat! Hello, I am having a physics investigation about thermophysics stuff. I investigate how the rate of temperature increase inside a box alters by the colour of the box.. There are a few questions i want to ask: -a) Black box will abviously gets the hottest. But among red, blue...

Humans have colour vision - we have rods (which are quite sensitive to light) and cones (which come in three types, and whose different responses to light of different wavelengths our brains interpret as 'blue', 'green', and 'red'). Do any other mammals have colour vision? If there are any...

where is pink in the visible spectrum? it can't be between blue and red cos they're on the opersit ends... after red is infer red, and after blue is ultra violet?

why does the waters of the unpolluted oceans and seas have their own different natural colour? is it jus a mere reflection of the sky??

Well... this is part of a theory I have linking personality to colour.. sort of. DON'T post unless you have something special to say - ie. not my favourite colour is x...