Exploring Black & White Materials: Absorption vs. Reflection

In summary: Just a little correction: this statement is not really accurate because the sun is not a perfect blackbody.
  • #1
theobromine
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True black materials theoretically absorbs all wavelengths of visible light. True white materials reflect all wavelengths of light.

If a material which was black at room temperature was heated up to incandescence so that it was emitting all visible wavelengths (white light), and then light was shone at the material, would it:

a) Absorb all light, as it was black when not incandescent
or
b) Reflect all light, in essence behaving as a white object

Insight would be much appreciated!
 
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  • #3
theobromine said:
Summary: True black materials theoretically absorbs all wavelengths of visible light. True white materials reflect all wavelengths of light.

What happens when a material which is ordinarily black is heated to incandescent?

If a material which was black at room temperature was heated up to incandescence so that it was emitting all visible wavelengths (white light), and then light was shone at the material, would it:

a) Absorb all light, as it was black when not incandescent
It still absorbs all light. If you shine a flashlight on the sun it does not reflect off the sun. It is brighter than your flashlight because it emits more light to the flashlight than it absorbs from the flashlight, but it does not reflect or scatter your flashlight.
 
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  • #4
Dale said:
It still absorbs all light. If you shine a flashlight on the sun it does not reflect off the sun. It is brighter than your flashlight because it emits more light to the flashlight than it absorbs from the flashlight, but it does not reflect or scatter your flashlight.
Thanks, that's helpful.
 
  • #5
Dale said:
If you shine a flashlight on the sun it does not reflect off the sun. It is brighter than your flashlight because it emits more light to the flashlight than it absorbs from the flashlight, but it does not reflect or scatter your flashlight.

Just a little correction: this statement is not really accurate because the sun is not a perfect blackbody. It is true if we replace the word sun with perfect blackbody at several thousand Kelvin.
 

Related to Exploring Black & White Materials: Absorption vs. Reflection

1. How do black and white materials differ in terms of absorption and reflection?

Black materials absorb most of the light that hits them, while white materials reflect most of the light. This is because black materials contain pigments that absorb all wavelengths of light, while white materials contain pigments that reflect all wavelengths.

2. Why do black materials appear darker than white materials?

Black materials appear darker because they absorb more light, while white materials appear brighter because they reflect more light. This is due to the difference in the amount of light that is absorbed and reflected by the pigments in each material.

3. How does the color of an object affect its absorption and reflection properties?

The color of an object is determined by the wavelengths of light that are absorbed and reflected by its pigments. Objects that appear black absorb all wavelengths of light, while objects that appear white reflect all wavelengths. Other colors reflect only certain wavelengths, resulting in a unique color appearance.

4. How can we use black and white materials in scientific experiments?

Black and white materials can be used in experiments to study the properties of light and color. By comparing the absorption and reflection properties of these materials, we can better understand how light interacts with different surfaces and how colors are perceived by the human eye.

5. Can black and white materials be used for practical purposes?

Yes, black and white materials have many practical applications. For example, black materials are often used for solar panels because they absorb more light and convert it into energy. White materials are used for reflective surfaces, such as road signs, to increase visibility and safety. Both black and white materials are also commonly used in photography and printing processes.

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