Environment is a place for human survival and activities. There are various types of environmental pollution, including air pollution, water pollution and soil pollution. According to the nature of pollutants, there are biological pollution, physical contamination and chemical pollution; According to the forms of pollutants, there are waste gas pollution, waste water pollution, solid waste pollution, noise pollution, radiation pollution, light pollution and so on. According to the causes of pollution, there are domestic pollution sources, industrial pollution sources, agricultural pollution sources and traffic pollution sources. According to the scope of influence, there are global pollution, regional pollution and local pollution.
So what is dust pollution? I'll talk about life first. I wonder if the students have noticed the things around them and the chalk in the teacher's hand. Most chalk is marked with the word "dust-free". Actually? Is there really no dust in chalk? No, when we clean the blackboard, we can see obvious chalk dust. The reason is actually very simple. "Dust-free" chalk dust can settle down in a few minutes because of its large particles, but floating dust still exists. Since dust-free chalk was widely used in schools, students and teachers bid farewell to the dusty era and entered a basically dust-free era. Dust can settle in a few minutes because of its large particles, but the harm of chalk dust to human body can not be ignored. Therefore,
Second, the topic is put forward
The particles of chalk ash have a strong ability to adsorb germs, and the composition of chalk is alkaline. At the same time, chalk dust contains a lot of heavy metal cadmium. Harmful bacteria, alkaline substances and heavy metal cadmium can easily cause inflammation, dryness, atrophy, itching, chapped, lung cancer, emphysema and kidney damage to teachers and students' respiratory system, skin, ears, nose and throat. Students are responsible for cleaning the blackboard and are in the classroom from morning till night. Chalk dust is more harmful to the health of underage students with poor resistance. Therefore, our research group decided to conduct a comprehensive understanding and investigation on the hazards of chalk dust.
Third, related information.
On February 16, Shanghai's "East View and Wide Angle"-interviewing NPC deputies on the proposal of "chalk dust that cannot be ignored" is an important form of NPC deputies' deliberation and a concentrated expression of ordinary people's voices. Therefore, every NPC meeting has many proposals, a considerable part of which involve major social and economic issues, some of which seem insignificant, but they are closely related to the lives of ordinary people and are also highly valued by people. Today, the motion group of the general assembly received such a motion, and the problem he called for was chalk dust in the classroom. Chen Xintian, deputy director of Putuo District People's Congress Standing Committee, made this suggestion. His family can be said to be a family of teachers, and Chen Xintian himself has been a teacher for decades. Therefore, I am deeply touched by the harm of chalk dust. Chen Xintian, deputy to the National People's Congress: It has been my wish for many years to eliminate chalk dust in the classroom. I was a teacher, my wife is still teaching, and my mother is an old teacher. Nowadays, the educational facilities and instruments are very advanced, but it is precisely the problem of chalk dust that has not been solved. It can be said that representative Chen Xintian's motion speaks the voices of many school teachers and students. Yesterday and today, we visited some primary and secondary schools at random, and the results were the same. As the saying goes, music never leaves the mouth, and boxing never leaves the hand. As soon as the teacher walks into the classroom, he can't live without this little chalk head. I rubbed and rubbed, and the dust raised was too much for people to eat. It is said that most teachers used to like to wear those traditional sleeves to prevent dust from entering the cuffs to stain sweaters and shirts. Chalk dust not only makes teachers feel uncomfortable, but also makes students in the same environment feel uncomfortable, especially those sitting in the first and second rows. (Interview)-(Teacher: That's all we can do when we wipe. When we wipe our hands, we are covered with dust. Teacher: Cleaning the blackboard will cause a cough. Teacher: Every time you clean the blackboard, the students have to open the window. Teacher: When the teacher cleaned the blackboard, the students sitting in the front row were disgusted. Student: If you clean the blackboard, sometimes chalk dust will fall into your mouth and eyes, which is very painful. I can only order eye drops when I go home. Cough and cover your mouth; Powder is white when it falls to the ground; The first and second grade classrooms are very small, and the first row is close to the blackboard, which will be stained with chalk dust. ) (……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………… The classroom environment should be a place to protect the health rights of teachers and students. 10 NPC deputies responded positively to this motion and seconded it. Most of them are teachers, and some NPC representatives from enterprises. "Chalk dust" seems to be no small matter. It is the first time that chalk dust has been put forward as a motion of the National People's Congress, but the call for eliminating chalk dust has long existed. According to a primary school general manager, this question was first raised ten years ago. So, is it because the problem is too small to solve? The director of general affairs said that six or seven years ago, a kind of "dust-free chalk" called dust-free appeared. Perhaps, people think that the problem is solved. However, although many teachers are holding this so-called "dust-free chalk" now, the problem of chalk dust has not been solved. (Interview)-(Teacher: This is not satisfactory either. There is a lot of powder. [This hand is just chalk dust] Yes. Teacher: The chalk slips and can't be wiped clean. This chalk is not smooth enough to wipe clean. Teacher: Up to now, chalk without ash has not been really used. According to the address on the chalk box, we followed the map to find a local chalk manufacturer. In its small salesroom, we saw piles of "dust-free chalk", totaling more than 50 boxes. We made a small calculation, assuming that all primary and secondary schools in the city use this pile of chalk. If each teacher consumes two pieces of chalk in a class, then in less than half a day, all 50 boxes of chalk will turn into chalk dust, fall on the heads of teachers and students, and be inhaled into the respiratory tract. The person in charge of sales in this factory said that they have been producing "dust-free chalk" for ten years. When asked if they could solve the problem of chalk dust, they explained it like this. (Interview)-("Dust-free Chalk" Sales Manager: In the dictionary, dust means flying, called dust. What our chalk says is that after being erased, it falls more and flies less, which is called dust-free. Specifically, it is dust, and there is no absolute dust-free. ) For many years, few people in society care about the technological innovation of chalk. On the contrary, manufacturers have withdrawn from the market. It is understood that this factory is the only one still producing chalk in Shanghai. According to reports, in the past ten years, they have spent a lot of effort on color and feel, and the formula of raw materials is still mainly handed down by the master. The manufacturer also said that he had enough psychological preparation. A few years later, chalk was completely replaced by modern electronic teaching AIDS, but there seems to be no better improvement between traditional chalk and modern electronic teaching AIDS. In the interview, teachers who use chalk every day disapprove of this statement. (Interview)-(Teacher: The method is always more difficult than it is. As long as we think more about the health of teachers and students, there is always a way. Teacher: High technology can be invented. I don't think solving the problem of dust-free chalk is the biggest problem. Put this work on the agenda. Don't think that this chalk can only write. This idea cannot be studied. Teacher: Can an eraser be like a vacuum cleaner? Teacher: Can the blackboard be dried as soon as it is blown, like a mobile phone dryer? Teacher: chalk is used in primary and secondary schools and universities. If there is a breakthrough in quality, the market potential is great. Shen Jianping, Education Department of Pudong Social Development Bureau: As the administrative department of education, we are very grateful to the deputies to the National People's Congress, and we are eager for the relevant manufacturers to develop a new product. Chen Xintian, deputy to the National People's Congress: This problem is not big, but it belongs to the basic problem. We now have a beautiful environment in Shanghai and attach great importance to greening, but the small environment in our classroom is not ideal. This problem should be solved. (Wu Xiaofeng) Editor's Note-What the representative Chen Xintian said is very reasonable. As we introduced in yesterday's "Wide Angle of Oriental Vision" program, in recent years, the Shanghai municipal government is constantly strengthening the transformation of the urban environment. This year, the number of new public green spaces will reach 300 hectares. However, while we are striving to build Shanghai into a "bluer sky, greener land and clearer water", we really should not ignore some small environments in the big environment. How to improve our classroom environment is a problem worthy of attention and needs to be solved as soon as possible. In addition, the motion submitted by Chen Xintian to the General Assembly also made us feel the role of people's representatives. They come from the people and care about the masses. Their opinions and suggestions are really the voices and demands of the masses. Giving full play to the role of NPC deputies can make our government work more perfect.
Fourth, study the investigation process.
Basic idea:
People pay more and more attention to knowing that dust pollution is becoming more and more serious. The diffusion of chalk dust and dust pollution were studied, and the harm and treatment of dust pollution were discussed.
② Dust pollution; Chalk ash expansion
③ The source of loose dust; environmental protection
④ Analyze how to prevent the harm of chalk dust.
At present, there are many related products, but they are expensive and have some defects. We want to make a breakthrough in this respect.
step
Stage main task stage goal
In the first stage, the information of chalk dust is obtained by searching information on the Internet.
Design survey scheme in the second stage
Visiting experts and teachers all know the harm of chalk dust to human body.
The third stage summarizes the problem
Make a report, make an invention
Fruits and reaction measures
Research achievements of verbs (abbreviation of verb)
Hazards of chalk dust: chalk is nontoxic, but chalk dust is harmful! The particles of chalk ash have a strong ability to adsorb germs, and the composition of chalk is alkaline. Harmful bacteria and alkaline substances can easily cause inflammation, dryness, atrophy, itching, chapped, lung cancer, emphysema and kidney damage to the respiratory system, skin, ears, nose and throat of teachers and students. Students are responsible for cleaning the blackboard and are in the classroom from morning till night. Chalk dust is more harmful to the health of underage students with poor resistance.
Dust pollution directly threatens people's lives, especially exposure to dust pollution will cause many cardiovascular and respiratory diseases. The increase in the incidence of asthma and bronchitis this year is a typical manifestation of the aggravation of dust pollution. Dust pollution has the greatest impact on the elderly and children. The chemical composition of dust can directly determine the harm of dust to human body. For example, dust containing free silica, also called silica dust, can cause silicosis, and the higher the silicon content. Toxic substance dust containing lead and manganese can cause corresponding kinds of poisoning; Organic dust such as cotton, hemp and grain can cause pharyngitis, tracheitis and allergic reaction. The smaller the dust particles are, the longer they float in the air, and the more chances they will be inhaled. Generally, dust particles below 5 microns can reach the depths of the lungs, causing lung diseases, namely pneumoconiosis. Because the mass of chalk dust is too small, the effect of airflow can not be ignored. Through the study of chalk dust diffusion, we get the following four phenomena:
1. When the initial velocity and height of chalk dust are fixed, the airflow resistance makes the diffusion distance of chalk dust decrease inversely proportional to the mass of chalk dust, that is, the greater the mass, the farther the falling point. However, if its mass is too small and it is lifted by updraft, it does not apply to the above conclusion.
2. From the falling time, it can be found that the theoretical value is quite different from the actual value. After many experiments, it is ruled out that the data difference is caused by error, and the difference changes with the change of height, and there is a trend of increasing with the increase of height.
3. From the three rows of displacements, we can find that although the same chalk dust is used in the experiment, the diffusion distance of chalk dust is different, and the displacement difference between adjacent displacements is also different. The chalk dust with the largest displacement basically gathers together to form a dense chalk dust landing point, but most of the chalk dust is concentrated and scattered in the middle displacement part.
4. The image of chalk dust landing formed by this test method is oval-like, that is, the widest part of chalk dust diffusion is mostly in the middle displacement, and the nearest part is slightly more than the farthest part. Although the detention range of chalk dust in the nearest place is slightly larger than that in the farthest place, the amount of chalk dust is basically the same.
At present, the contents of metal elements, lead, manganese and barium in chalk on the market are low, but the contents of cadmium are high. After being inhaled by human body, cadmium is mainly stored in liver, kidney and bone tissues, which has obvious damage to these tissues. The main pathological changes caused by long-term exposure to cadmium compounds are emphysema and kidney damage, and the condition can develop progressively. The early symptoms are weakness, emaciation, dizziness, insomnia, dreaminess, anorexia and neurasthenia. Emphysema progresses slowly, and the patient has progressive dyspnea. At present, the content of lead, manganese and barium in chalk on the market is low, but the content of cadmium is high. After being inhaled by human body, cadmium is mainly stored in liver, kidney and bone tissues, which has obvious damage to these tissues. The main pathological changes caused by long-term exposure to cadmium compounds are emphysema and kidney damage, and the disease can develop progressively, with early manifestations of weakness, emaciation and dizziness. Emphysema progresses slowly, and patients have progressive dyspnea, increased activity and palpitation. Cadmium is also the most likely to aggravate activity, accompanied by palpitations. Cadmium is also the most conductive.
Seven, survey feeling:
Through the research project, I learned a lot of knowledge and cultivated my ability. Our project is "the harm of chalk dust to human body", which was put forward by our team leader. We are ambitious to make a chalk eraser model, then apply for a patent and so on. Now I think it is wishful thinking. However, we have not given up, and we are still moving towards our goal step by step, although our ability is limited. This is my first feeling when I joined the project. Let me learn to stick to it here.
-Pan Jun
I learned a lot from this project. For example, the harm of chalk dust to human body, how to prevent the harm of chalk dust to human body, and the collective spirit of the team. Persistent efforts can get things done well, and so on. Halfway through, there were only three pawns in our group, but because the ideas of the three people could not be connected, various contradictions occurred. Finally, we United, and now no one can destroy our feelings. Also, our original project instructor abandoned us, but we stuck to our own project, making it even more difficult to create three worlds independently. But when we met with difficulties, many teachers enthusiastically helped us and supported us, so we didn't finish the project successfully. Wu Zhixiang
Research study is my first contact and my first independent action, but I have gained a lot. It makes me learn a lot, and makes me feel that the unity among my classmates is very important. In this research topic, we often encounter some troublesome things. These questions make me wonder where to start. We have never heard of photo shoots. I wanted to give up in the face of difficulties, but with the encouragement of my classmates and teachers, I persisted. I want to express my sincere thanks to them for successfully completing this project. -Zheng.
Mentor's feelings
The members of this research group are conscientious and proactive. All the research steps are orderly and the activities are colorful. In the process of investigation and study, a lot of valuable information has been obtained, which is very helpful for them to understand the people and things around them. As a tutor, I deeply realize that they have great potential to tap. As long as they keep this research spirit, they will certainly do well in many aspects. I believe I can do many things in the future.
-Tan Anhua