Everyone knows that maple leaves turn red in autumn, like a burning flame, very beautiful. But you all know why maple leaves turn red in autumn.
I was puzzled, so I looked up the book and searched the Internet. I see.
It turns out that some chemical changes will take place in deciduous trees in autumn and winter, so that useful substances or some tissues contained in the original leaves can be recycled and stored in stems or roots after decomposition. Among them, there is a special pigment called anthocyanin, which is a "chameleon" and is red in acidic solution. With the change of seasons, the temperature and sunshine increase or decrease correspondingly, and the main pigment components in leaves also change. Autumn comes, the temperature drops, the light weakens, and the anthocyanin composition changes, while the leaf cell sap of red-leaf trees such as maple leaves is acidic, so the whole leaf is red.
I did another experiment according to the book: I picked some red leaves from the tree. When I got home, I chopped the red leaves. Then I boiled them in water, and the water turned red. Then I added some dilute hydrochloric acid to the water, and the water became redder. Finally, I made a small cup of soapy water and poured it into the water. The red water miraculously turned blue.
This experiment proves that red leaves turn red when exposed to acid and blue when exposed to alkali are anthocyanins. In autumn, the leaves will produce anthocyanins, which are just acidic and will turn red.
In life, there are many things worth observing. As long as you find them with your heart, you will gain something.
2. When it comes to science and technology, people may first naturally think of things that seem out of reach, such as artificial earth satellites, manned spacecraft and atomic bombs. She often gives people a feeling of being above others. In fact, with the rapid development of science and technology, science not only serves the cutting-edge science and technology, but also permeates our daily life more and more. Technology and life have long been inseparable, and technology is everywhere. During the summer vacation, I participated in the summer camp for young journalists in Beijing. During the days when we were away from our parents, the teacher asked us to inform our parents about our activities every day. When staying in a hotel in Beijing, it is extremely difficult to find a public telephone because people are different and can't walk around casually. IC phone cards prepared before leaving are often lost. At this time, I will especially envy those "group friends" who have mobile phones, and I will deeply feel the convenience that mobile phones bring to people.
In China Science and Technology Museum, we saw the old hand-cranked telephone that can only be seen in TV and old movies, and we also learned how inconvenient it is for people to contact in the primitive way in the era when there is no telephone. Every time I see the footage of party member risking his life to send messages and losing contact signals in the battle, I can't help thinking, if I had a mobile phone, wouldn't I have avoided these unnecessary sacrifices? From time to time, I will be more aware of the power of science. Science has not only changed the whole world, but also changed our lives. Science is all around us.
A few years ago, people called mobile phones "mobile phones" and pagers "BB machines". Making and owning them is something to show off. It seems that this is a symbol of money and status, and it is synonymous with "big money" and "fashion". Today, with the rapid development of science, the telephone has spread to thousands of households. From white-collar workers in companies to ordinary vegetable farmers and even people who collect waste products, their dependence on it is increasing day by day. It occupies an increasingly important position and becomes an important means of communication in people's life and work. It is obvious to all, from fixed telephone to mobile phone, from single communication tool to color screen and video mobile phone, it makes people's life colorful. Seeing this, you can't help sighing at the rapid development of science and technology.
As a new generation of middle school students, while enjoying our new life, we should set up lofty ideals and aspirations, love science, learn science well and create a new life from childhood. Every student here probably has the same dream. When they grow up, they want to be scientists, produce more scientific research results and contribute to the construction of the motherland and human civilization. This is a lofty goal. In fact, we learn scientific knowledge not only to become scientists, but also to adapt to the ever-changing new life.
Therefore, from now on, we should cultivate a strong interest in learning, study hard scientific and technological knowledge, learn all kinds of cultural classes well, read more popular science books and actively participate in various scientific and technological activities. There is no limit to human wisdom. No matter the Challenger explosion in the United States or the global computer virus upgrade, it will never stop the scientific and technological progress of mankind. "Knowledge is power", Bacon's famous saying inspired many people who are eager for knowledge. Now, let's use it to motivate ourselves, be a new generation that loves science, and write more brilliant poems for the future of our motherland!
Science and technology, as the name implies, is science and technology. Everyone should be familiar with science and technology, because it is used and served by us and it is closely related to our lives. It not only brings us spiritual pleasure, but also physical comfort. In this rapidly developing society, science and technology represent a kind of spirit as well as a kind of strength. It represents an innovation and a civilization. It is an important symbol to measure a country's comprehensive national strength, and science and technology occupy an important position in any field.
Science and technology are widely used, including military, biological and aerospace. Technology has been integrated into life and enriched it. In the street, at home, in the classroom and in the shop, technology has brought convenience to people. It can be said that human beings created science and technology, and science and technology also created human beings. Human beings and technology are interdependent. Our food, clothing, housing and transportation are inseparable from technology. Let me take you into the wonderful life of science and technology.
Clothes make the man, and everyone needs clothes to dress himself. Take a closer look at the clothes we wear. Acrylic, silk and pure cotton … are slim, warm and healthy … countless, which bring us warmth, comfort, health and happiness. These clothes can't be made without technology. Let's say warm clothes can make you feel warm. In the cold winter, we don't have to wear thick down jackets and sweaters, but only a light and soft warm clothes can make us feel warm. You see, isn't this the convenience brought by technology?
Let's see what we eat. Now, we should pay attention to everything we eat, that is health! With the progress of society and the development of human beings, people's concept of food has also changed, not only pursuing delicious food, but also demanding healthy and nutritious food. Nowadays, many people eat high-tech foods, such as protein powder, calcium tablets and dietary fiber. , are studied by scientific and technological personnel. Today, we talk about a high-tech food: vegetable juice drink. Vegetables are an important source of vitamins and minerals and the guarantee of life and health. In terms of nutrition and health care, vegetables can provide comprehensive nutrition and prevent or even treat nutritional deficiency. However, because the taste of vegetables is not accepted by most people, scientists and technicians have improved vegetables and made a delicious vegetable juice drink, which has become an ideal future drink.
Let's take a look at the most common material for building houses-cement. Cement is a brownish gray powder made of limestone and clay. When it is used, it becomes hard and abnormal when mixed with water. In recent years, with the development of new technology, functional cement has been continuously developed. There are many kinds of high-tech cement, such as glass cement, light cement, rubber cement, sugar water cement and color-changing cement. They all have their own characteristics and are the crystallization of science and technology. Today I'm going to introduce you to a magical cement: color-changing cement. This kind of cement is not only an ideal building material, but also can be used to forecast the weather. Also known as "meteorological cement", it is blue when the weather is dry. Once wet, it turns purple; If it rains, it will become a bright rose after absorbing water. It changed color because cobalt dioxide was added to the cement. Look, isn't it amazing? In fact, this is also the surprise and convenience brought by technology.
Speaking of cement, let's talk about cars. The car is a convenient and important means of transportation. Whether traveling or going to work, it is convenient to have a car. Looking back at the history of automobile development,1On July 3rd, 956, the first medium-sized truck named "Jiefang" was born in China, ending the history that China could not make a car. Later, Dongfeng brand domestic cars were produced; The first 2.2-ton military off-road vehicle; First adopt 60 dump trucks; The first coach and the first red flag car, etc. Today, Honda, Mercedes-Benz, BMW ... these are the crystallization of science and technology, releasing the charm of science and technology. It is the development of science and technology that has brought us today's convenient cars. It can be seen that science and technology have made great contributions to us, and everything we have today cannot be separated from science and technology.
Science and technology have played an important role in food, clothing, housing and transportation, facilitating and benefiting mankind.
In the rapidly developing 2 1 century, technology is not mysterious. It is hidden by your side. As long as you observe it carefully, you can also invent your own technology. Perhaps the small technology you invented, after being modified and perfected by experts, has become a veritable scientific and technological product, and can also make great contributions to the future society and mankind.
Students, science and technology is a magical and great cause, which brings infinite joy and convenience to our lives, allowing us to understand, discover and create science and technology. I believe that technology comes from life, and life cannot be separated from technology. Let's use our wise eyes to discover technology!
4. If I am the composition of the designer of the high-tech Olympics.
Dream is a never-ending sail, moving slowly with the turbulent waves; Dream is a string of colorful bubbles, some embrace the kind sun and fly to the blue sky, some are big and round, but they soon disappear; Dream is a colorful world, full of fantasy, childlike interest and freedom ... and we are a lively fish in this world, swimming freely here. ...
On the evening of July 1 20065438+3, people all over the world sat around the TV and watched the 1 12 plenary session of the International Olympic Committee held in Moscow. Under the gaze of more than one billion pairs of eyes, the good news that Beijing won the right to host the 2008 Olympic Games came. Chinese people all over the world are extremely excited, and decades of dreams have finally come true at this moment! The Olympic bid is successful, and I really want to be an Olympic designer. Nowadays, science and technology are advancing by leaps and bounds. If I am an Olympic designer, I must be a high-tech Olympic designer.
If I am a designer of high-tech Olympics, under my design, I will hold a modern Olympic Games: where athletes want to go, as long as they enter their addresses, they can immediately reach the places they want to go through the space tunnel. Then it is not limited by the venue. For example, we can participate in track and field competitions in Sichuan, gymnastics competitions in Shanghai, and weightlifting competitions in Xinjiang ... If there is insufficient oxygen in the air, we can supplement oxygen from the oxygen plant. If the indoor temperature is not suitable or the weather is not suitable, we can invent an indoor and outdoor weather thermostat. ...
If I were a designer of the high-tech Olympics, I would consider all aspects of the athletes' basic necessities: you don't need to dress yourself at all, just shout "get up" in bed and the robot will help you get dressed; When washing clothes, you don't need to wash them yourself. All you have to do is take off your clothes and put them in the bucket in the bathroom, and the robot will wash them for you and send them to you. Athletes don't need a chef for three meals a day. You just need to input what you want to eat on the computer in the kitchen, and the robot will send delicious food immediately. Athletes will live in a super high-rise building with 3000 floors. Our advanced elevator can climb 1000 floors in three seconds. ...
If I am a designer of the high-tech Olympics, I will make full use of high technology in the competition: in the football match, a small refrigeration air conditioner will fly behind each athlete; When raising the national flag, you don't need a flagpole. As long as you enter the champion's ranking on the computer, the national flag will fly slowly and the national anthem of the champion will be played automatically. ...
If I am the designer of high-tech Olympics, I will try my best to make the 2008 Beijing Olympic Games the brightest star in all previous Olympic Games.