85
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Why aren't rainbows blurred-out into nothing after they are produced?
This isn't quite how rainbows work. The standard explanation is that light bounces around inside each droplet, and getting reflected once, and exiting at an angle:
Image source
However, the real ...
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84
votes
Why are rain clouds darker?
Rain clouds are dark because the part of the cloud you see is in the shade.
Clouds are white because they contain tiny water droplets that scatter light of all colors equally in all directions. "...
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62
votes
Accepted
Why is the air inside an igloo warmer than its outside?
An igloo is not made from ice, but made from compressed snow. Snow is basically semi-frozen water or frozen crystalline water.
Contrary to intuition, snow has actually got very good insulating ...
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53
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Why does snow stay after a snowfall?
Just as a complement to Ziggurat's answer: you can try to estimate the time required for the sun to melt a certain quantity of snow by yourself.
The energy required to melt a mass $m$ of snow is $$Q=...
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47
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Accepted
Why does wind direction significantly affect sound propagation?
Since the mechanism is so well written on Reddit in here, I won't even try to rephrase it. Here it is:
Yes, wind has an effect on the speed of sound, and this effect has
interesting ramifications ...
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46
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Why do small patches of snow remain on the ground many days or weeks after all the other snow has melted?
A hidden assumption is that all of your remnant piles start with the same amount of snow. However your first photo seems to be adjacent to, and parallel to, a roadway. You mention you’re in Boston, ...
rob♦
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43
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Why aren't rainbows more common?
There are no billions of water drops in the air on any given day. Water in the air is normally in the form of vapor, not drops. For drops to form, the relative humidity should be 100% causing ...
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41
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Why aren't rainbows blurred-out into nothing after they are produced?
Your picture shows that an observer at X will see both the strongly scattered red light and the strongly scattered blue light, but he will see it coming from different directions.
That's the same way ...
38
votes
Accepted
Why is snow white when water has no color?
That's same for cloud, fog, wave splash and so on. Because of tiny size (but in large number) and irregular appearance, reflection and refraction occur in an irregular manner so the light is ...
- 1,387
36
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What did I just photograph? (rainbow way out of place)
As pointed out in the comment by @Rob, this is called a Circumzenithal Arc or colloquially, an "upside-down rainbow". Different to usual rainbows (which appear on the opposite side of the ...
- 30.1k
35
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Why aren't rainbows more common?
A number of conditions have to be just right in order to see a rainbow.
The Sun has to be visible in the sky. Rainbows don't occur on overcast days. The light hitting the raindrops needs to come from ...
- 41.7k
24
votes
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What are these strange rays in the sky?
Those are definitely anticrepuscular rays. The Sun was in the antipodes of the point of convergence of those rays in the sky, when you took that image. Here you have a similar observation:
These are ...
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21
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Why is the air inside an igloo warmer than its outside?
Although igloos are often associated with all Inuit and Eskimo peoples, they were traditionally used only by the people of Canada's Central Arctic and Greenland's Thule area. Other Inuit tended to use ...
- 235k
20
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Why do small patches of snow remain on the ground many days or weeks after all the other snow has melted?
I doubt that there is a single reason. Many particular combinations of factors may result in differences between the melting rate and the quantity left over at some time (which depends on both melting ...
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17
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Why is snow white when water has no color?
Snow is simply a random collection of snowflakes and bits of irregularly shapen bits of ice. Each of these is clear, but a small fraction of the light incident on each clear entity is reflected and ...
- 88.9k
17
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Accepted
Open or closed windows in a tornado?
Why did people open their windows before a tornado hit their home?
There is a significant pressure drop inside a tornado - It can be about 10% lower than ambient. So, when a tornado passes over and ...
15
votes
Why aren't rainbows more common?
The drop size has a direct correlation to the saturation of the colors in the rainbow. You can see examples here, notice how the rainbow is much brighter when the drops are larger, and the fades as ...
- 8,643
15
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Why aren't rainbows blurred-out into nothing after they are produced?
The picture in your question represents a halo rather than a rainbow: the rainbow is seen when the Sun is behind you, while halos appear when the Sun is in front of you.
The actual mechanisms ...
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12
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Why do small patches of snow remain on the ground many days or weeks after all the other snow has melted?
There are a number of reasons and the pictures handily show three of them
A snowplow probably left this (originally bigger of course)
A person might have shoveled this (same as above)
Shady
The ...
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11
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Why do we feel hot when temperature is relatively high even though it might be lower than our normal body temperature
We have to constantly dissipate all the heat we generate. Our body is constantly doing work, and the second law of thermodynamics tell us that we cannot do work with $\%100$ efficiency. That is some ...
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Why do small patches of snow remain on the ground many days or weeks after all the other snow has melted?
I'm not a physicist (I'm a chemical and software engineer), but I did grow up in Montreal before moving to the Rhode Island riviera in my 30s and Texas in my 40s.
There are a few reasons for this.
...
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Why is it hot before raining?
When warm humid air flows into cool air the humidity is condensed into rain as the warm air cools. The temperature rise your feeling is the warm humid air rolling into your cooler area before it rains....
- 106
8
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Why do small patches of snow remain on the ground many days or weeks after all the other snow has melted?
One way or another this phenomenon must involve the thermal mass of the ground.
About thermal mass:
When air temperature drops below freezing any snow that falls will be melted due to the ground being ...
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7
votes
Why is the air inside an igloo warmer than its outside?
Because it is heated up from the inside by people (or possibly small fires).
The snow walls work as a thermal insulator to the outside.
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7
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Is the downforce of rain on airplanes negligible?
The impact of new drops even in heavy rain has only a small effect.
From force x time = change in momentum
$$F\times 1 = 0.021 \times 10^{-3}\times 1000\times 9$$
where the 1000 is for the density of ...
- 13.7k
6
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If I shoot into a hurricane, can the bullet come back and hit me?
A 150 mph (241 kph) hurricane is still only blowing at 250 feet per second (76.2 m/s). A .270 caliber (6.8 mm) rifle has a muzzle velocity of about 3,100 feet per second (944.8 m/s) and a max range ...
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6
votes
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What causes the perceived intensity of the sun to change on a short timescale?
When you feel "heat" from the Sun, what you're actually feeling is the infrared radiation that the Sun emits. The reason infrared radiation feels hot is because your body is mostly water, and infrared ...
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6
votes
Accepted
Is it possible to find dry ice crystals lying around the base in Antarctica?
The equilibrium vapor pressure of carbon dioxide at -80 C is about 1 bar. The partial pressure of carbon dioxide in air is about 0.0004 atm. This tells you that CO2 will not sublime from air at -80 ...
- 34.3k
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