A short essay on popular science in physics urgently

"Eat the Noise".

Ball lightning Why does the moon look red during a total lunar eclipse

Hallucinations caused by blood cells in front of the retina

Cutting Beer Bottles

Crispy Popcorn

Porous frozen tofu

The Mystery of Infrasound Killing

The Physics of Frozen Fish

Get Energy from Trash

Why warm water freezes faster than cold water

Too much...

Both fog and clouds are formed by the condensation of water vapor, except that the base of the cloud does not touch the ground, while the fog touches the ground. Therefore, it can be said that fog is a cloud on the ground. When you are climbing Huangshan, Lushan, and Mount Tai, you may have such an experience:

Sometimes from the bottom of the mountain, the mountain is covered with white clouds, and the mountains are hidden in it, but when we climb to the top of the mountain, the mountains are clearly visible, but the white clouds are under our feet, and people are like in the fog.

Depending on the level visibility, fog can be classified as heavy fog, dense fog, heavy fog, medium fog, and light fog. The horizontal visibility distance of heavy fog is less than 50 meters; The horizontal visibility distance of the dense fog is between 50 and 200 metres; The horizontal visibility distance of fog is between 500 and 1000 m, and the visibility distance of light fog is more than 1000 m.

According to the different causes, fog can be divided into radiation fog, advection fog, vapor fog, uphill fog, frontal fog and so on. Radiation fog is formed when the ground air is cooled by radiation at night to reach a state of supersaturation of water vapor. This fog mostly occurs at night and in the morning when it is clear, breezy and has plenty of moisture near the ground.

The appearance of radiation fog generally indicates that the weather is fine on the day, so there is a saying that "ten fogs and nine sunshines". Advection fog is caused by the horizontal flow of air. When warm and moist air flows through the cold ground or sea surface, the lower layers of the air cool down as they touch the ground or sea surface, causing the water vapor to condense into a fog.

The appearance of advection fog generally indicates that rain is going to fall within two or three days. Frontal fog occurs in frontal areas where warm and cold air masses collide. This kind of frontal fog often appears in the rainy season in China, and it is also a harbinger of rainy weather.

The place with the most fog in China is Mount Emei in Sichuan. Between 1953 and 1970, there were an average of many foggy days, almost every day.

Fog has a big impact on navigation, aviation, and crops. For example, once the sea voyage encounters dense sea fog, the ship may lose its direction, and even run aground, run aground, collide and other accidents; It will be difficult for the aircraft to take off or land in foggy weather; Crops can be affected in consistently foggy and cold weather, both yield and quality.

Cloud formation is mainly caused by condensation of water vapor.

We all know that in this layer of the atmosphere more than ten kilometers from the ground, the closer to the ground, the higher the temperature and the denser the air; The higher you go, the cooler the temperature and the thinner the air.

On the other hand, the water surface of rivers, lakes and seas, as well as the water of soil, animals and plants, evaporates into the air at any time and becomes water vapor. When water vapour enters the atmosphere, it becomes clouds that cause rain, or condenses into frost and dew, and then returns to the ground, seeping into the soil or flowing into rivers, lakes and seas. Later, it evaporates (sublimation) again, and then condenses (condensation) and declines.

The cycle goes on and on.

After the water vapor enters the lower atmosphere from the evaporation surface, the temperature here is high, and the water vapor contained is more, and if this hot and humid air is lifted, the temperature will gradually decrease, and at a certain height, the water vapor in the air will reach saturation. If the air continues to be lifted, excess water vapor will be precipitated. If the temperature there is higher than 0°C, the excess water vapor condenses into small droplets; If the temperature is below 0 °C, the excess water vapor condenses into Xiaoice crystals.

When these small water droplets and Xiaoice crystals gradually increase to the point where the human eye can recognize them, they are clouds.

It is common to see that the sky is sometimes cloudless, sometimes cloudy, and sometimes cloudy. Why are there clouds in the sky and no clouds? How exactly are clouds formed? What is it made of?

Clouds floating in the sky are made up of many tiny water droplets or ice crystals, and some are made up of small water droplets or Xiaoice crystals mixed together. Sometimes it also contains some large raindrops, ice and snow particles, and the base of the cloud does not touch the ground and has a certain thickness.

Cloud formation is mainly caused by condensation of water vapor.

We all know that in this layer of the atmosphere more than ten kilometers from the ground, the closer to the ground, the higher the temperature and the denser the air; The higher you go, the cooler the temperature and the thinner the air.

On the other hand, the water surface of rivers, lakes and seas, as well as the water of soil, animals and plants, evaporates into the air at any time and becomes water vapor. When water vapour enters the atmosphere, it becomes clouds that cause rain, or condenses into frost and dew, and then returns to the ground, seeping into the soil or flowing into rivers, lakes and seas. Later, it evaporates (sublimation) again, and then condenses (condensation) and declines.

The cycle goes on and on.

Through the above weather, some relevant physical knowledge is revealed, what are the advantages and disadvantages of the weather to people's lives, and how to prevent and pay attention to things;

Such as liquefaction, vaporization, artificial precipitation, snow can keep wheat warm, and so on.

We are now going to talk about a substance. This substance was first found on the sun and only later on Earth.

Everything grows on the sun. The sun is a huge ball of fire that gives us light and heat. Since the invention of the telescope, people have used telescopes to study the sun and see the spots and sunspots on the surface of the sun.

During a total solar eclipse, you can also see a huge flame erupting from the surface of the sun. But what the chemical composition of the sun is, you can't see it with a telescope alone.

In 1825, a French philosopher named Comte arbitrarily said in his philosophical lectures: "The chemical composition of the stars is knowledge that man can never acquire." There seemed to be some truth to his words.

The Sun is the closest star, but it is 100 million kilometers away. Who can fly to the sun so far away to take some material and analyze it in a chemical laboratory? Moreover, the temperature on the surface of the sun is 6,000 degrees Celsius.

This cannot be done in any way.

However, the philosopher's conclusions were made a little earlier. In 1859, less than three years after Comte's death, a chemist and a physicist collaborated to invent an ingenious method to determine the chemical composition of distant celestial bodies such as the sun and stars without leaving the earth.

This chemist is Bunsen, this physicist is Kirchhoff. The method they invented is called spectroscopy.