Why are some clouds black?

 Clouds are visible droplets or ice crystal aggregates composed mainly of water in the atmosphere and also contain a variety of other relatively small amounts of chemical substances. We can see clouds because water molecules gather around the dust (condensation nuclei) in the air. They scatter sunlight in all directions, allowing us to see the appearance of clouds clearly.

The size of small water droplets and small ice crystals in the cloud is larger than the wavelength of the incident light, so light of various wavelengths in the sun is scattered by these water droplets and ice crystals to make the cloud appear white. Of course, this is all when the clouds are thinner.

If the cloud is thicker, the sunlight will not show through the cloud, and most of it will be absorbed. At this time, the cloud will look gray and black.

Why does it take longer to urinate when drinking?

Because when you are drunk, it takes longer to urinate. Many people think that alcohol has a diuretic effect, but this view is wrong. Due to the effect of alcohol, our ability to feel the bladder becomes dull. Generally speaking, when the bladder reaches 200cc, we will want to go to the toilet. But when you are drunk, your bladder reaches its maximum limit and you still can’t feel the urge to pee. The capacity of an adult’s bladder is about 400-500cc. Therefore, when you are drunk and want to go to the toilet, your urine volume must be twice as much as usual. It also becomes longer.

Why is the sea so "blue" so charming?

Sunlight is composed of seven colors of red, orange, yellow, green, cyan, blue, and purple. The absorption of light by sea water is related to the wavelength of light. Long-wave light (red) absorbs faster, and short-wave light (blue) absorbs slowly. When sunlight hits the deep ocean below a hundred feet, only a piece of blue light remains, and other colors of light are absorbed. Therefore, The sea reflected in the eyes is so blue that it is so charming. Moreover, the deeper the sea, the stronger the blue.

Why do animals’ knees bend backwards?

Human knees are undoubtedly bent forward, but for some animals, such as cats, dogs, cows, horses, and birds, their "knees" seem to be bent backward.

In fact, those animal "knees" that you think are bent backwards are not knees at all.

The bones in the human thigh and calf are called "femur" and "tibia" respectively. For animals such as cows, what you think of as the "thigh" is actually the "tibia", so it should correspond to our calf. And their real thighs, the "femurs" are located above the tibia, closer to the hip area, so the real knees are hidden very close to the body. The same goes for chickens and ducks. The "thighs" you usually eat are just their calves.

Those structures that we mistake for "knees" are actually equivalent to our ankles, and the so-called "calves" below are part of the soles of the feet.

In addition to humans, what other animals shed tears?

Speaking of animals that shed tears, they have been more or less found in all terrestrial species of the vertebrate subphylum. This is actually a very normal phenomenon. Animals "tear", sometimes to moisten the eyes and provide nutrition to the cornea; sometimes because of eye inflammation or infection; sometimes to remove foreign bodies, etc.

But in our human worldview, tears always carry some emotional color, so when you see other animals "tear", there will always be comments like "all things are alive". But in fact, some scholars believe that only humans shed tears because of emotions, especially human sobbing or weeping, which basically does not happen subjectively in animals.


Although some scholars believe that many animals have sad emotions, in the natural environment, if animals cannot hide their emotions, letting tears blur their vision or sobbing will increase the risk of predation.

Why are there no square celestial bodies?

Whether it is planets, stars, or other celestial bodies, they are often spherical or nearly spherical. Why hasn't a square celestial body been discovered? This starts with the formation process of celestial bodies.

Celestial bodies will capture surrounding dust, gas and other materials during their formation. This process is called "accretion." In the early stage of formation of a celestial body, collisions and fusions with various substances will make it form a crooked irregular shape, but as the mass of the celestial body increases, the effect of gravity begins to become stronger, and some prominent edges and corners will collapse due to their own gravity. Melt into the celestial body, and finally form a stable sphere or sphere-like shape.

The only natural square objects in the universe are crystals, such as pyrite. But their volume is much smaller than that of celestial bodies.

How does the plane land in Antarctica?

We know that even a car is difficult to drive on a road that is frozen by ice and snow, let alone a large aircraft that requires precise control? But mankind has indeed overcome this difficulty and built the airport to Antarctica in the icy and snowy land.

There are two main types of airport runways in Antarctica: land-based rock runways and ice-snow runways. The former is no different from an ordinary airport runway, which is a pavement constructed of rock and cement; while the latter is compacted by ice and snow. Such a runway requires special machinery and equipment to ensure that the road is flat and solid and can generate sufficient friction.


The Antarctic continent has a very limited area suitable for building an airport, and the wheeled aircraft we usually take have very strict requirements on the runway. Therefore, most of the aircraft types are small and medium-sized aircraft equipped with skid landing gear. In order to flexibly respond to the transition between land and snow runways, aircraft on the Antarctic route are generally equipped with convertible take-off and landing wheels and sled board landing gear. However, it is very difficult to take off with the skid-board landing gear, and booster rockets are used to increase speed when necessary.



Zeigarnik effect

  As a freelancer, you have to fight procrastination every day. "I've made up my mind many times, but I just can't change it. Is it because I'm slow or slow?". In fact, many procrastinations are irrational. Many obstructions are imagined by myself. So distract, postpone, avoid confrontation. It's cool to procrastinate, and it's cool to procrastinate all the time, so I can't do it. Concentration is also related to physical strength. When the physical strength is exhausted, it is even more difficult to concentrate. You’ll tell yourself: I’m too tired to do this—okay, another perfect procrastination.   In 1927, Bruma Zeigarnik's senior research found that people are more likely to care about unfinished and interrupted work than completed work. This is the Zeigarnik effect. For example, we often don't care much about what we have got, but we will especially cherish what we have worked hard but haven't got. Therefore, the TV series will tell you

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Hebei Xingang Pharmaceutical Co., Ltd is located in the industrial park of Zhao County, Shijiazhuang, Hebei, near the world-famous ZhaoZhou Bridge. Our facility neighbors the Qinyin Expressway and 308 National Highway on the east, and it neighbors the Jingzhu Expressway and 107 National Highway on the west. It is located 30 km from Shijiazhuang High-speed Train Station and 50 km from Shijiazhuang International Airport. Our company mainly focuses on the research, production and retail of rifamycin and its derivatives, and pharmaceutical raw materials and intermediates. Our products mainly include, Rifamycin S Sodium, Rifamycin S, 3-Formyl Rifamycin SV, Rifamycin SV Sodium, Rifampicin, Rifandine, Rifaximin, Rifapentine, Rifabutin, Rilmenidine, and so on. We are currently the world’s main manufacturer of anti-tuberculosis drugs and rifamycin and its derivatives. Hebei Xingang Pharmaceutical Co., Ltd was established in 1996. Upon establishment, the company had a clear developmental goal o

Moroccan football team: "The most familiar stranger"

   When I was still in college ten years ago, I led a sightseeing group of more than 30 Moroccan students. Before meeting them, my general impression of the Moroccans was that they are from North Africa but closer to the Arab world. They have religious beliefs, are used to worship, and are inextricably linked with France.   When I saw the real person, I realized that the North Africans in front of me were actually a group of children playing with each other and having fun in time. They were about the same age as me at the time. I have all kinds of nicknames and nicknames. During the process of taking them to Badaling, the Summer Palace and Houhai, two classmates and I, together with more than 30 Moroccan students, realized "cultural integration" and "world unity" in the small group to some extent.   During the World Cup in Qatar, I was surprised to find that the little-known Morocco team, which was eliminated in the group stage of the last World Cup, after miraculou