# Mass of colours

1. Feb 17, 2004

### alchemist

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 to colour the objects..
will the difference in mass due be to the amount of anergy absorbed through the different colours???

2. Feb 19, 2004

### chroot

Staff Emeritus
The objects would not have different masses due to their colors alone.

If you shine a light on the objects, and one of them gets hotter than the other due to its greater absorption of the light, then yes, the hot would would be slightly more massive, due to its larger internal energy.

If you keep both objects at the same temperature, however, there will be no difference in their masses.

- Warren

3. Feb 22, 2004

### 1100f

If they are identical, have the same mass and the same composition, how could they be of different color?

4. Feb 23, 2004

### HallsofIvy

Re: Re: mass of colours

alchemist said, in his first post: " 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 to colour the objects."

In other words, each object is identical except for a thin coat of paint.

The question does make sense but the answer is, of course, that color will have absolutely no effect on the mass.

5. Feb 23, 2004

### deltabourne

Correct me if i'm wrong, but since
$M = V \times D$,
if $V_{color1} = V_{color2}$ and $D_{color1} = D_{color2}$, won't the masses be the same?

6. Feb 25, 2004

### arivero

If seems to me that the question is about the frequency/energy/mass of photons, is it?