On foggy days why are we able to see a short distance in front of us but decreasingly so the farther ahead you look?

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On foggy days why are we able to see a short distance in front of us but decreasingly so the farther ahead you look?

In: Earth Science
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Fog makes it harder to see things because it gets in the way, blocks out part of the image so it’s a little fuzzy. The further away you look the more fog there is between you and what you’re looking at. Because there’s more fog there’s more stuff in the way that makes it hard to see. So the further out you look, the more fog you’re looking through, and the harder it is to see.

Imagine a screen window. You can see through it, because the screen only blocks a little bit of light. Most of the light still gets through.

Now, imagine a hundred screens all on top of each other. Now, you probably can’t see through that, because each screen blocks a little bit more and all of the screens put together block most of the light.

It’s the same with fog. The water particles are small and spread apart, so light can still pass through, but a little bit gets blocked. The more space there is between you and what you’re looking at, the more fog there is and the more light gets blocked.

Fog is *mostly* transparent.

In front of you, you’re looking through a little bit of fog. It’s still mostly transparent.

Far away from you, you’re looking through a *lot* of fog. It might still be mostly transparent, but all the bits that aren’t begin to add up.

It’s the same as how a *sheet* of plastic wrap is clear, but a *roll* of plastic wrap isn’t.

The simple answer is diffusion. The more water droplets there are for light to pass through, the more opportunity for light to be scattered, the more light is scattered the more opaque something looks. So less droplets close to your face means less light scattering, so slightly blurry, further away object have more room to scatter light and therefore are obscured.