eli5: What is the difference between a mirror and a white object?

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I mean, what does a white object do? Absorbs nothing, reflects all light back.

What does a mirror do? Absorbs nothing, reflects all light back.

Having the same characteristics, how does a mirror reflect an image and a white object, a white texture?

In: Physics

18 Answers

Anonymous 0 Comments

The terms you can look up for this exact thing are [diffuse vs specular reflection.](https://www.physics.louisville.edu/cldavis/phys299/notes/lo_speculardiffuse.jpg)

**Mirrors are specular reflection** – they bounce all visible light and their surface is smooth enough that the bumps are smaller than the wavelength of light. That means each light wave “bounces true” and the outgoing angle is the same as the incoming angle.

**White objects are diffuse reflection** – they bounce all visible light, but in random directions. The surface has bumps that are bigger than the wavelength of light. There’s no image because the directions are scattered. So like white paper or a white sweater. They’re bouncing all the visible light but the fiber surface is too rough to produce a specular reflection.

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