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How should parents give reasonable guidance to children who use new media to become younger?

Chen Qingwen, an associate professor at Tongji University, pointed out that parents should balance the opportunities and risks of the Internet when guiding their children to surf the Internet. Photo courtesy of respondents

A chart based on interview data of Chen Qingwen’s team. Photo courtesy of respondents

  I believe many people have had this experience: in some public places, "Xiong Haizi" played games or watched videos with electronic devices such as mobile phones and tablets, and the volume was so loud that parents turned a blind eye. Relevant research reports show that in China, children’s use of new media tends to be younger and more entertaining.

  On the one hand, new media devices that can be networked, such as mobile phones and tablets, have grown up with a new generation of children and once became a "part" of their bodies; On the other hand, the powerful educational function and interpersonal communication use of new media also make it a sharp weapon for learning and communication.

  As the mother of a post-00 generation child, Chen Qingwen, an associate professor at Tongji University’s College of Art and Media, faces the same problem: How and how often do children use new media? How should parents guide their children to use new media reasonably?

  With these questions, Chen Qingwen and his team randomly interviewed 30 families of children aged 3-10 in Shanghai to learn about children’s use of new media, parents’ attitude and involvement in children’s use of new media, and children’s views on parental involvement. On this basis, suggestions are given, and the research results are published in the core journal "Journalist" in August 2019.

  From "TV Children" to "New Media Children"

  As a post-1970s generation, Chen Qingwen admitted that he "grew up watching TV". When he was a graduate student at Fudan University 15 years ago, he studied the newly-emerging children’s channel in China. She said that the transition from "TV children" to "new media children" was even faster than the growth of a generation. And this change has brought a kind of trouble to parents: it is difficult to guide children to use new media reasonably with reference to their own experience.

  Some people may ask, how can they bring up the next generation when there was no TV in the older generation?

  "Because the new media is more interactive, participatory and creative than the traditional media, but without learning and guidance, children may just regard the new media as TV or game consoles." Chen Qingwen explained that, at the same time, new media are everywhere, and the content is all-encompassing, which is very different from traditional TV and other media. You can leave TV at home, but you can’t live without the Internet and mobile phones. In modern cities, "portable" and "always online" have become the common points for people to use new media.

  Chen Qingwen felt that "new media children" were born from the moment parents provided their children with new media equipment.

  Among the 30 families interviewed, one-third of the children have their own new media equipment, and the other two-thirds share it with their parents, many of whom will leave their unused new media equipment for their children to use. In terms of use, most children play games, followed by watching videos, and the third is the homework assigned by the school.

  According to statistics, more than half of the children use it for a long time, especially on weekends, almost for more than two hours a day. In the trend, many children in the kindergarten group have used new media for a long time, and the use time tends to lengthen with age. In addition, compared with the primary school group, the kindergarten group has a higher proportion of its own new media equipment, which shows that the use of new media is younger.

  In March this year, the Research Report on the Internet Use of Minors in China in 2018 jointly issued by the Youth Rights Protection Department of the Central Committee of the Communist Youth League and China Internet Information Center showed that as of July 31, 2018, the number of underage netizens in China reached 169 million, and the Internet penetration rate of minors reached 93.7%, which was significantly higher than that of the national population (57.7%) in the same period. According to the report, this is a direct manifestation of the expansion of Internet coverage and the decline of mobile traffic charges in China in recent years, and it is also closely related to minors’ strong interest in the Internet, strong learning ability and great application demand.

  Don’t let machines take the place of parents’ company

  In the interview, the research team found that children’s use of new media is mostly due to lack of companionship, especially preschool children. Because parents are busy and have no friends to play with, children have to turn to mobile phones and tablets; With the increase of age, more and more children choose new media.

  Some parents even choose to use new media instead of themselves to accompany their children. In public places such as restaurants, children are often seen watching videos while eating, perhaps just to let their parents "have a good meal". "She is good with this and doesn’t make any noise, as long as she doesn’t make any noise." A mother said.

  The interview also found that with the increase of age, more and more children are more willing to choose new media than playing with friends; And the older children are, the less satisfied they seem to be with their new media use time. Most of the respondents in the primary school group felt that their use time was insufficient, and one girl felt that two hours a day was not enough.

  "When parents use new media instead of accompanying their children, the actual price paid is likely to be huge." Chen Qingwen pointed out in the research report, "As they get older, they are more likely to rely on new media. At this time, even if their parents want to accompany them, they may continue to immerse themselves in communication with machines. When machines replace humans to accompany children, even if people come back, the relationship between children and machines is unbreakable. "

  Chen Qingwen combined expert opinions and personal experience to give some suggestions to parents. "If you want to control underage children’s use of new media, try not to let them own their own equipment, just lend it to him, that is to say, give children the right to use it, while parents retain the right to control it. As for the balance between control and privacy, you need wisdom."

  She also said that although the current academic research is inconclusive about when to start controlling children’s use of new media, she feels that parents who are determined to control their children should take action as soon as possible. "It would be much better to let him know that parents should take care of it early than suddenly."

  Why can other children play computer games, but I can’t?

  In this "equipment battle", "children crying and parents yelling" is a common scene. The research team found that most children’s tricks are crying and "lai", and they can play as long as they can until their parents take away the equipment.

  Interestingly, on the question of whether parents are worried about their children’s use of new media, parents’ attitudes are polarized: 17 are worried, and 13 are not worried, either very supportive or very opposed.

  In the interview, some parents thought that "this is a trend" and "this thing will be accepted sooner or later", so they were not worried at all. A mother said: "everyone has it, but they just can’t fall behind." If she doesn’t understand, she feels like she is behind others and can’t keep up. "

  The attitude of parents who hold opposite opinions is also very clear, and their concerns are mainly reflected in three points: First, they are afraid of their children’s addiction; The second is to worry about the harm to vision; The third is to worry about the negative impact of inappropriate content such as violence.

  Chen Qingwen believes that such "two extremes" attitude makes parents’ work of disciplining their children in trouble. "Why he can I can’t, this is a child’s question. For example, children will say that classmates can use computers when they go home. Why can’t I? "

  Another reason is the change of family education style in China. “‘ Authoritative education ’ It is not easy to work. In the past, parents could answer no, but now they are likely to get a crying and keep asking. After all, children’s energy is much better than ours. "

  The research team also found that, as in the TV era, the way parents intervene in their children’s use of new media is mainly "restriction", and the time limit is more than the content limit.

  Most parents in the interview only know that their children are playing games or watching videos, but they don’t know what games or videos their children are playing. Some academic studies believe that restrictive guidance strategies can not only effectively help solve the problems that children may encounter on the Internet, but also easily lead to the decline of the quality of parent-child relationship or frequent conflicts.

  For children who are out of control, whether they cry, lose their temper or cheat, the parents interviewed said: "Let her cry", "Ignore her" or "yell at him", and some parents will be patient and reasonable, but children will still enter the cycle of yelling if they don’t listen.

  The mother of a 9-year-old boy said that she usually talks reason first and scolds him if she doesn’t listen. If she scolds him, she will have to yell at him at him at a higher volume. If she doesn’t, she will have to be punished, such as not using new media for a few days or increasing the number of homework. Most parents can insist on not using their children’s noise, but the children’s crying or losing their temper will continue.

  Academic research proves that parents’ positive intervention is more effective.

  "We just did a small-scale interview in Shanghai." Chen Qingwen said, "If you want to give scientific advice, you need to do extensive and long-term investigation and research in different cities and rural areas across the country."

  But before that, some countries encountered these problems earlier than China, and their academic research may provide reference.

  Chen Qingwen introduced that since the 1980s, the research on parents’ involvement in children’s media use has been popular in the United States. After 1990, the American government emphasized the role of parents in family policy, and related research received more attention. The research points out that the two main intervention methods adopted by parents are "making rules" and "restricting"; The actual behavior of parents can be divided into positive intervention methods such as parent-child discussion and negative intervention methods such as prohibiting or restricting use, and parents adopt the mode of sharing viewing between parents and children.

  In another paper on the use of new media by minors by British scholars in 2007, the author divided the intervention strategies of parents for their children to use new media into four categories. In addition to joint use and restricted use, parents will also adopt "technology restrictions", that is, use technology software or set restrictions on their children to prevent them from using unauthorized digital media content; And monitor children’s use of websites, letters and games in different ways. Their conclusion is that when parents take active measures to intervene their children’s use of new media, such as sharing or discussion, the negative influence of their children’s use of new media can be effectively reduced.

  Domestic research on the media also believes that parents’ intervention can bring positive results.

  For example, in the psychological aspect, the correct intervention of parents and families can reduce teenagers’ psychological anxiety, help build self-confidence and self-esteem and affect teenagers’ mental health; In terms of learning and risk reduction, parents’ active intervention in media use can improve teenagers’ learning effect, reduce the possible negative impact of violent content in the media, affect the formation of children’s gender role attitude, reduce children’s fear response to media content, and reduce some network risks that children may encounter.

  At the same time, parents’ ideas and the motivation and methods of intervention are extremely important.

  Foreign studies have found that the more parents want the Internet to have a positive effect on their children and think that the Internet will have a negative impact on their children, the more they will get involved in their children’s use of new media. Domestic research also points out that the more time online is strictly restricted by parents, the more recreational motivation teenagers tend to use the Internet.

  "The key point may not be whether children should use new media or how to use new media at all, but where the parents are and where the children’s minds are. Studies in different fields have pointed out that modern society is busier than before, and how parents create a happy parent-child environment will become an increasingly important issue. Quality companionship between parents and children is one of the necessary conditions for shaping parents. " Chen Qingwen’s interview report wrote.

  Communicate with your child with your heart

  What do children think of their parents’ control? The interview results show that on the whole, half of the children think that their parents are reasonable; At the same time, with the growth of children’s age, the proportion of recognition of parents’ intervention control has increased. And "making rules together" and "keeping your word" have become the common standards for children to measure the rationality of parental discipline.

  Taking nine children in the kindergarten group in the interview report as an example, Min Min, a 4-year-old (all minors below are pseudonyms), feels that his parents are much more in charge; Tingting, 5, feels that her parents don’t care much because they are reasonable. Zhu Zhu, a 5-year-old, said that she was afraid of her father because he was very fierce when he was angry and would say, "I’m telling you! I’m telling you! No matter how, I will kick you downstairs "; Kiki, Doll and Lingling, both 6 years old, are afraid of their mother and think her mother is too fierce.

  Among the 21 children in the primary school group, 13 children feel that parental control is reasonable, 5 children feel unreasonable, and 3 children are uncertain. Xiao Han, a third-grade student, told the interviewer that she felt that the parental control was sometimes reasonable and sometimes unreasonable. The unreasonable reason was that the mobile phone was forcibly taken away before the agreed time. "My mother said several times that she would play for me for 10 minutes. I didn’t expect that when it was almost two minutes, she said that it was 10 minutes. I didn’t want to, so my mother dragged me away. She said that it was evening and I couldn’t play any more."

  The interview report suggests that from the perspective of social environment, there are two urgent matters: first, timely education courses related to new media literacy should be provided at different stages of children’s growth; The second is to improve parents’ ability to master new media and new technologies.

  "Not all parents have the time and energy to participate or study independently. I think we can start with school education and issue some principles and suggestions for children to take back to their parents." Chen Qingwen explained.

  In addition to improving their understanding of new media and technologies, parents should also attach importance to communication between parents and children and accompany their children to use new media by guiding participation. Especially in the method of making rules, parents need to talk to their children often. "In fact, kindergarten children have a very clear concept, this is good, how long should it take. If the rules are made by the children themselves, or if the parents discuss with him, the children will be more willing to abide by them. "

  When attending international academic conferences, Chen Qingwen often discusses these issues with foreign scholars: when to give children new media equipment, how long the screen time should be in a day, and when to let children have their own social media accounts. "Although some organizations will give suggestions, for example, the screen time is no more than one hour or two hours a day, and general social software suggests that people are over 14 years old, but parents have different ideas, different social situations, different family situations, and different children, so you can refer to some research-based suggestions, but in the end you have to find a way that suits you. I don’t think there is an absolute standard."

  "According to the needs" is Chen Qingwen’s main basis. Her son rarely contacted new media when he was in kindergarten, but when he saw that other children had their own mobile phones, he said that he also wanted to have their own mobile phones. But this wish has not been realized until now that his son is going to middle school, because his son has no need to carry a mobile phone. When she entered middle school, her son needed a computer for some of his homework. The school asked for a laptop for her child, so she bought the laptop she wanted, but only if it was used for study and could not be loaded with games. "At present, the school has just started, and there are still any problems in the future. I am also walking and watching."

  "In our research, we found that intentional is better than unintentional. As long as you are intentional, children can feel it. My suggestions are: teach students in accordance with their aptitude, learn from each other, and communicate with your heart. From the perspective of communication, intentional communication can enhance feelings and reduce misunderstandings, which is actually the most effective method. " Chen Qingwen said. (China Youth Daily China Youth Network Trainee reporter Wei Qimeng)

Customers buy more than 10,000 yuan graphics cards online but receive bricks and mineral water? Merchant response

  Jimu journalist Liu Xiaobin

  Mr. Du from Shenyang, Liaoning spent 15,288 yuan to buy a video card through the idle fish platform, but received a brick and a bottle of water. On April 10th, the staff of the graphics card seller responded to a journalist who had a dispute with Mr. Du in a previous online transaction. The money has been returned but has not yet been returned. Mr. Du’s second card purchase is still on the platform. Because of fear of loss, he gave a brick and a bottle of water this time.

QQ screenshot 20220410183726.png

  Video screenshot

  The video circulating on the Internet shows that at a railing with barbed wire, a woman handed a paper box from under the barbed wire, and a man opened it on the spot. There was a packaged object and a bottle of water in the box. In the video, the man said that the packaged object was a brick.

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  Video screenshot

  On the afternoon of April 10th, Jimu journalist contacted Mr. Du, the publisher of the video. He introduced that he lives in Huanggu District, Shenyang City, Liaoning Province. On April 2, he paid 15,288 yuan on the idle fish platform and bought a graphics card at an online store with an address in Xuanwu District, Nanjing City, Jiangsu Province, ready to install it on the computer to play games. At 4 o’clock on the afternoon of April 9, he went downstairs to get the parcel, opened it in front of the courier, and found that it was not a graphics card, but a brick and a bottle of water.

QQ screenshot 20220410183839.png

  Video screenshot

  Mr. Du told Jimu journalist that at the end of March, he saw an advertisement on the Internet saying that a new graphics card was to be listed. It happened that he needed it. On March 29th, he placed an order on the idle fish platform and paid 15,490 yuan for it. Later, after receiving the goods, he felt that he didn’t meet his requirements, so he proposed to replace a product. He had many conversations with the seller in the middle. On the afternoon of April 9, before receiving the new express, he received the last payment of 15,300 yuan returned by the platform. For this matter, Mr. Wei, a staff member of the seller of the video card, told the Jimu journalist that the courier containing bricks and water was indeed sent through them, but there was a dispute with the buyer in the last online transaction.

  Mr. Wei introduced that at the end of March, Mr. Du paid more than 15,000 yuan to buy a graphics card. At that time, he had clearly told Mr. Du that the graphics card "will not be returned once it is sold, unless there are quality problems", but after Mr. Du received the graphics card, he asked for a return. After the return, he also asked for more than 100 yuan less, so the two sides had a dispute. Mr. Wei said that in repeated communication, Mr. Du spent another 15,288 yuan to buy a graphics card.

  "The price of graphics card is different every day, sometimes the price difference is relatively large, and the price loss and courier fee will need to be borne by the seller. For the first time, the loss of that graphics card was about 800 yuan, and I was angry. In addition, I did not receive the first graphics card returned by Mr. Du at that time. I was worried that the loss would be even greater and I had to deliver the goods as scheduled, so I delivered a brick and a bottle of water. " Mr. Wei said that this matter is more complicated and there are reasons for it.

  On the afternoon of April 9, Mr. Du didn’t sign for the express delivery, and he has asked the express delivery company to return it, and Mr. Du has complained about this to the idle fish platform.

Under the new pattern of beauty industry, Fang Yuyou’s new idea of national brand development

The rise of "Yan value economy" has promoted the rapid development of the beauty industry, and also brought this industry into a critical stage of transformation and upgrading. From basic skin care to effective skin care, the beauty industry is undergoing a profound change. In this process, the Matthew effect of "the strong will always be strong" has become increasingly apparent. Domestic head brands take large single products as the main competition track, and technology-driven has become the key to achieve rapid growth.

However, how to find a balance between single product innovation and scientific ecological construction is a challenge faced by many enterprises. In this context, the "2023 Keyan Trend Conference" hosted by Jumeili attracted the attention of the whole industry, and the industry elites gathered together to discuss the future development direction of the cosmetics industry. Among them, Fang Yuyou, co-founder and CEO of Polaiya, gave a new idea.

Fang Yuyou explained in detail the road of enterprise’s transformation from operating genotype to science and technology, and elaborated on the switching of Polaiya’s two capability systems. The first switch took place in 2017, when the enterprise changed from simple TO B thinking to to TO C’s refined operation thinking, and began to change from a single online channel to an online and offline mixed mode; The second switch took place in 2020-2023. He proposed to use products to drive brands, and stressed that the R&D and marketing capability systems must be upgraded simultaneously.

Looking back on the development of Polaiya in the past 20 years, Fang Yuyou said that in the Internet era, emerging platforms such as Tmall and Tik Tok had a profound impact on the cosmetics industry. "It is very important to maintain the mentality of startups."

He also explained in detail how these factors can help enterprises achieve high-quality growth from the perspectives of big single product strategy, refined operation, product strength and R&D capability. In his view: "R&D is a bottomless pit, with a long time period and more investment. But as long as we persevere, one day we will change from quantitative change to qualitative change. "

For the future cosmetics market, Fang Yuyou is full of expectations. "Although the environmental consumption is now downgraded, the cosmetics market still has a scale of 400 billion to 500 billion, and it can even reach a trillion scale in the future."

He said that in the future, he will continue to insist on technology-driven product innovation, constantly enhance brand strength and product strength, and promote the high-quality development of China’s beauty industry.

With the rising of domestic products, the gap between domestic brands and international brands is getting smaller and smaller, forming a new pattern of industry competition. Only by keeping up with the pace of the times, daring to challenge and innovate can brands be in an invincible position in the fierce market competition.

Reporting/feedback

Speed does not lose high-speed rail! How does badminton, the king of ball speed, fly?

Speaking of badminton, I think everyone is familiar with it. Even if you are not a badminton fan, you will often see players in various sports venues or squares, and you will be right.Lindane, Li Zongwei.When famous players hear about it.


However, even fans who often play ball may not have noticed it.Details of badminton flight.

Why is badminton designed like this? Does it always fly with its heavy ball head facing forward? How far can badminton fly? Does it spin when it flies?Presumably these questions have aroused everyone’s curiosity, so let’s walk into the text together ~

Part 1: Flip of Badminton

Anyone who has played badminton will notice a phenomenon, that is, when the ball flies towards you, it is almost always.Ball head in frontThe gesture. Put yourself in the other’s shoes, and your opponent will certainly see the same phenomenon. Then there is only one possibility, that isAfter each side hits the ball, badminton will turn over.Then turn around and fly back. The question is, is the U-turn completed at the moment of hitting the ball? Maybe we take it for granted.

Fig. 1 (a) a snapshot with an initial velocity of about 18.6 m/s and an initial angular velocity of about 206 rad/s (with an interval of 5 ms); (b) Snapshots with an initial velocity of about 10.4 m/s and an initial angular velocity of about 28 rad/s (interval of 6.5ms). | The picture is from the literature [1]

Unfortunately, the answer is not like this. As shown in the above picture, the moment of hitting the ball is basically atAbout 1msIt’s done, but it’s usuallyAbout 20msThe ball can be turned over. And then go through itDamping oscillationIn order to make its ball head point in the direction of speed. In order to show this process more intuitively, we draw the relationship between the ball head pointing and the speed direction in Figure 2.Angle φEvolution over time. amongτ, τ and τThey respectively represent the time from the first turning to the ball head facing forward, the damping oscillation time and the characteristic time to reach stability.

Fig. 2 Evolution of included angle in two cases. | The picture is from the literature [1]

It can be seen that after 0.1-0.15s, badminton seems to have a forward posture, so except for some special hitting situations, weIt is difficult to capture with the naked eye.The process of rapid turnover adjustment of badminton after hitting the ball. So … Does this flip behavior of badminton have anything to do with its own structure?

Fig. 3 Force analysis of badminton when traveling | The picture is from the literature [1]

The answer is yes. Badminton byCork ball head and skirt structure made of goose feather/duck feather or plastic.Composition, in which the ball head is heavier and the skirt structure has a larger cross-sectional area. We might as well abstract this feature as identified by B and C in the figure.Large mass and large cross-sectional areaSkirt area andSmall mass and small cross-sectional areaThe ball head area of.

When flying, assuming that the direction of the ball head is not consistent with the direction of the speed, and there is an included angle φ, the air resistance acting on B and C will generate a moment with the center of mass G as the reference point respectively. On the one hand, the skirt structure has a large cross-sectional area and air resistance.FBigger, on the other hand, BG is longer than GC, so the ball will inevitablyRotate counterclockwise around the center of mass until the ball head points in the direction of speed..

Figure 4 Badminton shape schematic. | The picture is from the literature [1]

If the above weight distribution is easy to think of, then aboutWhy did badminton choose an opening angle close to 45?Perhaps few people have thought about it. In fact, this is closely related to whether badminton can experience flipping and achieve stability faster. Some scholars have recreated the shape and mass distribution characteristics of badminton with small iron balls and skirt structures made of plastic, and released it freely in the way of skirt structure facing down in water, so that it can turn over during sinking, as shown in the following figure.How does its opening angle affect the turnover and stabilization time?.

Fig. 5 How the opening angle affects the turnover and stabilization time. | The picture is from the literature [1]

Visible, opening angle is too small and too big is not conducive to the stability of the flip, and fromThe range of 30 to 90.Will experience a stable and fast platform area. Obviously, the opening angle of badminton falls in this area.

Part 2: the flight path of badminton

Different from tennis, badminton’s flight trajectory is greatly influenced by air resistance because of its light weight.Seriously deviate from the shape of parabola. Generally speaking, the equation of motion followed by badminton flight can be written.

Among them, and are the mass, density and cross-sectional area of badminton, respectively, and the speed,UandgIs the vector of velocity and acceleration of gravity, and is a constant related to the test conditions. It is not difficult to understand that in addition to the gravity term that makes it do oblique throwing, the ball will also receiveResistance whose magnitude is proportional to the square of velocity and whose direction is opposite to velocity.. And the specific trajectory is made up ofSize and direction of initial velocityDecide. For badminton, we can define a quantity related to its flight characteristics, which is called pneumatic length.

For the badminton we use, this distance is about 4.6m, which determines that the final stable speed of the badminton is U=6.7m/s when it falls freely and vertically. In the picture below, we can see the flight trajectory of badminton at different initial speeds.Comparison between calculated value (solid line) and actual value (scattered point)It can be seen that the motion equation can predict its trajectory well.

Fig. 6 Comparison between the calculated value and the actual value of badminton trajectory with different initial speeds. | The picture is from the literature [1]

So how far can badminton fly? We might as well look at the changing trend of the distance X traveled by badminton when it falls to the same height as the starting height after approximately throwing. According to the above equation of motion, we can find that this distance depends on the initial speed of badminton. willFlight distancexOn the relationship between initial velocity elevation angle θ and velocity magnitude uDrawing, you can get the following results.

Fig. 7 Variation of travel distance (m) with initial speed direction (elevation angle) and speed.

As long as you have played badminton, this picture must contain some information points that you can empathize with. For example, we find that no matter how hard we use, it seems that badminton always flies."come to an abrupt end" near a certain distance. The upper speed limit in this picture has been reached.140m/sHowever, the farthest distance that can be reached is only 13.83m. And the badminton court we use13.4m longThat’s why badminton can only hit the opponent’s backcourt from one side even if it tries its best, and it won’t play much even if it is out of bounds.

Fig. 8 Schematic diagram of badminton court

Some readers may ask, is it too exaggerated to set the upper speed limit to 140m/s? Can badminton fly so fast? In fact, it is not an exaggeration. In July 2013, Chen Wenhong, a Malaysian men’s doubles player, killed the ball under the ideal conditions in the laboratory.493km/hThe amazing speed is equivalent to136.9m/s. There are also reports that Danish player Codin has played.506km/hKill the ball record, namely140.6m/s. Even in the game, Codin played.426km/hSuper fast kill ball. thereforeBadminton is the deserved king of ball speed!

Fig. 9 The ultra-fast kill of Keding 426 km/h.

In fact, the flight trajectory of badminton is also related toType of ballRelated. We usually have two kinds of balls made of feathers and plastic. The following figure shows the difference of their flight paths.

Fig. 10 Trajectory comparison between feather ball and plastic ball. | The picture is from the literature [1]

On the one hand, with the same initial angle and speed,The reachable range of plastic ball making is larger than that of feather ball making.; On the other hand, feathering is near the highest point of flight.Greater curvature, trajectoryCloser to the "triangle".

Figure 11 Plastic balls


This is because under the condition of ensuring firmness and low cost,Plastic ball making tends to be biased.. This also means that feathering can be done without going out of bounds.Fly at a faster speed, thus reducing the opponent’s reaction time. Therefore, feather ball making is often more popular.

Part 3: the rotation of badminton

You may have noticed that badminton feathers areArranged obliquely in the same clockwise directionYes. Is this an irrelevant design? Actually, it is not. We can think of each feather as a thin plate, which will be subjected to when traveling in the fluid.The direction is perpendicular to the plane and opposite to the speed direction.The force, as shown in the figure below.

Fig. 12 Stress diagram of feather | The picture is from reference [1]


We immediately think that the resultant force of these forcesWill make the whole badminton rotate around the axis!When badminton travels at a faster speed, the greater the resistance, the greater the torque generated by the resultant force, which makes badmintonFaster rotation. If we multiply the angular velocity ω by the axial radius r of the feather to get the linear velocity at the feather, we will find that it is almost the same as the traveling speed.Linear relationship.

Fig. 13 Relationship between badminton rotational linear speed and traveling speed | The picture is from the literature [1]

Moreover, compared with plastic balls,The rotation speed of feather ball is obviously faster in flight.. The analysis shows that faster rotation will limit the precession of feather pelletizing, whichConducive to the stability of feathering in flight..

It seems that the flight details of badminton are really a university question. In this process, we can not only learn a lot.Physical knowledge, but also help to understand the ball.Flight path. After watching the push, the little friends quickly pick up the racket and see if the skills are improving ~

References:

[1] Cohen C, Texier B D, Quéré D, et al. The physics of badminton[J]. New Journal of Physics, 2015, 17(6): 063001.

[2] Badminton (Ball)-Wikipedia

[3] Kwan M W. It’sa Birdie… It’sa Shuttlecock… It’s Badminton: The Physics Behind the Badminton Shuttlecock[J].

[4] The world record of killing balls has reached a new high!


Editor: clouds open and leaves fall