Surface type and emission/absorption

In summary, the conversation discusses the difference between matt black and shiny surfaces in terms of their ability to emit heat, particularly in the infrared spectrum. Shiny surfaces, due to their free electrons, reflect incoming electromagnetic waves and thus are poor emitters. Matt black surfaces, on the other hand, have no free electrons and therefore absorb infrared energy, making them good emitters. The question of whether matt black surfaces absorb more infrared than other colored surfaces is also raised, with the conclusion that matt black is a good absorber and emitter across all colors, including visible light. The mechanism for this ability to emit heat is not fully understood.
  • #1
Jimmy87
686
17
Hi,

I am trying to get some information about why Matt black surfaces are such good emitters and shiny surfaces are not. When you try and look this up there really isn't much so I have tried to string what I have found together.

Shiny metal surfaces have free electrons which cancel the incoming electromagnetic wave by reflecting it hence they are poor emitters. This much I have found. Are Matt black surfaces good absorbers simply because they have no free electrons so they just absorb the infrared?

The other question I have is do Matt black surfaces absorb more infrared than say a coloured surface such as red? I can't see why Matt black is such a good absorber/emitter unless you are dealing with the visible spectrum as it will absorb all colours if it is black?

Thanks for any help offered.
 
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  • #2
Jimmy87 said:
I am trying to get some information about why Matt black surfaces are such good emitters and shiny surfaces are not.

emitters of what ?
define what you are referring to
 
  • #3
davenn said:
emitters of what ?
define what you are referring to
Sorry - I suppose infrared mainly. What is the mechanism to explain why black surfaces emit heat so well?
 

1. What is the difference between emission and absorption?

Emission and absorption refer to two different processes that occur when light interacts with a surface. Emission is the process of a surface releasing photons (light particles) while absorption is the process of a surface absorbing photons.

2. How does the type of surface affect emission and absorption?

The type of surface can greatly affect the emission and absorption of light. Different surfaces have different properties and structures that can alter how they interact with light.

3. What factors influence emission and absorption?

The factors that influence emission and absorption include the type of material, the surface texture, the temperature, and the wavelength of light.

4. How do scientists study surface emission and absorption?

Scientists study surface emission and absorption using various techniques such as spectroscopy, which involves analyzing the wavelengths of light that are emitted or absorbed by a surface.

5. Why is understanding surface emission and absorption important?

Understanding surface emission and absorption is important because it helps us understand how light interacts with different materials and surfaces. This knowledge can be applied in various fields such as solar energy, materials science, and environmental studies.

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