What happens to absorbed colors in colored substances?

In summary, when light hits a colored substance, the molecules in the substance absorb certain colors and reflect others. The absorbed colors are converted into heat energy and the remaining colors are what we see as the color of the substance. This process is known as selective absorption and is responsible for the vibrant colors we see in everyday objects. The amount of light absorbed and reflected determines the intensity and hue of the color, making each colored substance unique in its appearance.
  • #1
Karagoz
They say that substances have color because when light waves of all colors hit the substance, the atoms do absorb all the colors, except those that is its color.

Red substance is red because it absorbs all the color waves, but reflects the red waves.

But all the color waves the red substance absorbs, what happens to them? The atoms of the substance re-emit these waves right away at the same frequency? Or they emit at other frequency?
 
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  • #2
Karagoz said:
They say that substances have color because when light waves of all colors hit the substance, the atoms do absorb all the colors, except those that is its color.

Red substance is red because it absorbs all the color waves, but reflects the red waves.

But all the color waves the red substance absorbs, what happens to them? The atoms of the substance re-emit these waves right away at the same frequency? Or they emit at other frequency?

What you must first understand is that a "solid" is different than an "atom".

A solid has MORE stuff going for it than isolated atoms. There is something called "vibrational" spectrum, where the atoms that make up a solid can vibrate. There are also many other "collective" properties of a solid that are not present in isolated atoms. Most, if not all, of the common properties of a solid are due to such collective properties.

An absorbed light can do many things. One of them is that it causes greater the lattice vibration, i.e. the atoms in the solid to vibrate more vigorously. This is what we normally call heat. It is why a metal left in the sun gets heated up, because the absorbed energy has been converted into heat (vibration).

Zz.
 
  • #3
Karagoz said:
But all the color waves the red substance absorbs, what happens to them? The atoms of the substance re-emit these waves right away at the same frequency? Or they emit at other frequency?
They are immediately converted to thermal energy and depending on the conditions may then be re-radiated at a lower frequency or just lose heat via convection or conduction. For example, objects on Earth are warmed by the sun, absorbing its energy which is in large part composed of the visual spectrum. Then they get hot and re-radiate infrared and also lose heat to conduction and convection.
 
  • #4
Karagoz said:
They say that substances have color because when light waves of all colors hit the substance, the atoms do absorb all the colors, except those that is its color.

In addition to absorption, there could be wavelength-dependent scattering e.g. if pigments are present.
 

1. What is the difference between absorption and reflection of colors in colored substances?

When light hits a colored substance, some of the colors are absorbed and some are reflected. Absorption occurs when the molecules in the substance absorb certain wavelengths of light, while reflection occurs when the light bounces off the surface of the substance. The absorbed colors are not visible to our eyes, while the reflected colors are what we perceive as the color of the substance.

2. How do colored substances absorb light?

Colored substances absorb light through a process called selective absorption. This means that the molecules in the substance only absorb certain wavelengths of light, while allowing other wavelengths to pass through or be reflected. The absorbed wavelengths are determined by the chemical makeup and structure of the substance.

3. What happens to the absorbed colors in a colored substance?

The absorbed colors in a colored substance are converted into heat energy. When light is absorbed, it causes the molecules in the substance to vibrate, generating heat. This is why dark colored substances tend to feel warmer than light colored substances, as they absorb more light and therefore produce more heat.

4. Can absorbed colors be re-emitted by a colored substance?

Yes, some absorbed colors can be re-emitted by a colored substance. This is known as fluorescence or phosphorescence. When certain molecules in the substance absorb light, they become excited and emit light of a different wavelength as they return to their ground state. This is why some substances appear to glow or give off light, even in the absence of a light source.

5. How does the thickness of a colored substance affect the absorption of colors?

The thickness of a colored substance can affect the absorption of colors. Thicker substances tend to absorb more light than thinner substances, as the light has to travel through more layers of molecules. This is why some substances may appear darker or more intense in color when they are thicker. However, extremely thin substances, such as a thin film, can also exhibit unique optical properties due to interference effects.

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