Tagged Questions
2
votes
1answer
132 views
What is the cause of orange sky glow?
I live in the Netherlands and recently I have been seeing an orange glow in the sky at night, in the northwestern direction. What is the cause of this? And why is it in the northwestern direction (I ...
1
vote
1answer
132 views
Physics of Fireworks
This evening I saw the 4th July classic Fireworks in San Diego, and I was wondering about the most physical picture of what was happening. Does anyone have a good way to explain the detailed physical ...
19
votes
3answers
550 views
Why wet is dark?
When something gets wet, it usually appears darker. This can be observed with soil, sand, cloth, paper, concrete, bricks ...
What is the reason for this? How does water soaking into the material ...
9
votes
1answer
776 views
Why does paper become transparent when smeared with oil but not (so much) with water?
When I smear oil onto a scrap of paper and rub it in, the paper becomes quite transparent; but when I attempt the same with water it doesn't as much. Why?
5
votes
1answer
490 views
Why do mirages only appear on hot days?
A previous question asked why the road sometimes appears wet on hot days.
The reason is that when there's a temperature gradient in the air, it causes a gradient in the index of refraction, causing ...
