The answers to these questions that were not explained in "The First Lesson of School" are here

The First Lesson of School is also a science lesson full of knowledge. Are you curious about why the snow events in the Winter Olympics are afraid of snow? What is regenerated rice? Where does the stream in Saihanba come from? See the answers.

Compiled by New Media Editor Fang Yongzhen Image source: Screenshots from the show

The 2022 "First Lesson of the School Year" was broadcast as scheduled on the evening of September 1st. Have you watched it?

There are many scientific elements in this year's class. There are Winter Olympic champions who broke through weather barriers, academicians who cultivated golden seeds, Qinghai-Tibet scientific expedition teams who explored the mysteries of the earth, and Chinese astronauts who pursued their dreams of space... While telling stories of "struggle", it also brought us a scientific class full of knowledge.

However, there are some issues that were not explained in detail in the program, which must have caused confusion for many people. Below we will select a few points to explain to you.

Why are snow events in the Winter Olympics afraid of snow?

Winter Olympic champion Xu Mengtao said in the program that competitions are often affected by various weather factors. She recalled that at the 2022 Beijing Winter Olympics, the competition was postponed as she expected due to strong winds and heavy snow. So, why are snow sports afraid of snowy days in the Winter Olympics, which features ice and snow?

First of all, considering the uncertainty of natural weather processes, especially snowfall, international snow sports events, especially the Winter Olympics, generally use artificial snow to pave the snow tracks. The reason is that, on the one hand, artificial snowmaking technology is controllable and does not need to rely on the weather; on the other hand, the threshold of this technology is relatively low - as long as the temperature is below 0℃, the snow machine can work.

In the early morning, when the outdoor temperature is low, the natural snow is usually more solidified and hard, similar to "ice chips". Although this state of snow allows skiers to reach a faster sliding speed, it also makes the snowboard's grip less effective. Especially for novices, if the soft natural snow is not compacted, the snowboard is very easy to sink into the snow, causing accidents such as rollover and sudden stop.

In comparison, the quality of artificial snow is more controllable, especially high-quality "ice-like snow", which will gradually change from granular to powdery after the sun comes out. At this time, the snow quality is the best, soft and moderate, and is most suitable for various outdoor competitions using snowboards.

How does rice achieve “miraculous” regeneration?

In the program, Xie Huaan, an 82-year-old academician of the Chinese Academy of Sciences and a plant geneticist, introduced the seeds he has cultivated for more than 20 years, Ⅱ Youhang No. 1. It has been in space and has a strong regeneration ability. After its upper end is cut off, the lower end grows nearly 1 cm in one hour, and it can produce heading in 30 days.

I believe many people are curious about regenerated rice. What kind of rice is it? Regenerated rice is an "outlier" in the rice family. It has the ability to plant one crop and harvest two crops, which is "one crop, two harvests", similar to the "leek" of rice.

The secret of its regeneration is that when the first season of rice matures, there will be some axillary buds. After the first season is harvested, these axillary buds will be retained. Based on the original root system, these axillary buds will grow again and produce headings. After about 2 months, they will mature again and can be harvested. Regenerated rice saves the steps of re-raising rice seedlings and farming, saving seeds, labor, water, pesticides and money.

In fact, my country began to plant ratoon rice more than 1,700 years ago. In the 20th century, the yield of ratoon rice per mu in my country was only 150 to 200 kilograms. With the continuous application of scientific and technological means, in the early 21st century, the total yield of two seasons stabilized at more than 1,200 kilograms per mu. Raised rice has the advantages of high yield, low cost and good quality. The development of ratoon rice is of great significance to food security, but it cannot be planted at will. Raised rice has high requirements for growth conditions and must be planted in areas with suitable temperature, sunlight and water conditions to ensure stable and high yields.

Where did the Saihanba stream, which was once a desert, come from?

The "First Lesson of the New School Year" class also took us to the world's largest artificial forest farm - Saihanba. During the period, the forest farm staff took the children to the streams in the forest. The staff introduced that the formation of streams is also a benefit brought by planting trees.

It turns out that the formation of streams in nature is closely related to the surrounding environment. Generally speaking, streams on high mountains come from the melting snow on the top of the mountain, while on mountains without snow, streams come from rainfall. The soil and rock layers on the mountain have a strong water storage capacity, and the gaps between the gravel can store water. When it rains, some rainwater is absorbed by plants and then returns to the sky through transpiration; some rainwater seeps into the ground and becomes groundwater. The soil and rock layers are like sponges that absorb water. After the rain stops, water slowly seeps out and gradually forms streams.

One of the important ecological functions of forest ecosystems is water conservation. More trees can conserve more water. According to the Chinese Academy of Forestry, the million mu of forest in Saihanba has built a solid green barrier, conserving water and purifying 284 million cubic meters of fresh water for the lower reaches of the Luanhe and Liaohe rivers every year.

What technologies are used in the ever-changing cool classroom?

This year's "First Lesson of the School Year" innovatively adopts the form of "magic classroom + real-life classroom", upgrading the "new classroom" with new digital technology to create an immersive classroom with a strong sense of technology and the times.

The program uses macro lenses to show the microscopic world of rice seeds, time-lapse photography of the dynamic growth of regenerated rice, restoration of the process of drilling ice cores and rock cores, as well as a breathtaking J-15 model on site and a space station experimental cabin restored 1:1 through AR technology... China Media Group widely uses digital technologies such as AR (augmented reality) and CG to deeply integrate the program content, which not only broadens children's eyes but also further stimulates their imagination.

It is worth mentioning that the program also "moved" the classroom to the Wentian Experimental Module of the Chinese Space Station, and restored the experimental module in the studio at a 1:1 scale through AR technology. The crew of the Shenzhou XIV, who was "on a business trip" in space, also "came" to the program site through a connection, and the three astronauts led the students to visit the Wentian Experimental Module "on the cloud". The clear and smooth "video chat" between heaven and earth is the result of my country's "Tianlian" relay satellite. Wang Yaping, China's first female astronaut to walk in space, also appeared on the program site through a connection "on the cloud" to share with the students the unique experience of returning to life on Earth from space.

In short, this "First Lesson of the School Year" is still very interesting. Friends who missed it may want to take a look at it.

(The content of this article is compiled from Beijing Science and Technology News, CCTV News, Farmers’ Daily, CCTV Agriculture, Rural Areas and Farmers, Big Technology, etc.)

Produced by: Science Central Kitchen

Produced by: Beijing Science and Technology News | Beijing Science and Technology Media

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