2. Write a composition imitating bats and radars. I am a member of the frog family. We have superb skills in catching insects. When a small flying insect flies in front of our eyes, we will jump up and always catch the insect accurately.
And we "turn a blind eye" to static things, even if there are flies in front of us, they will not attract our attention. Scientists want to study our eyes and find that there are four kinds of nerve cells in our eyes, that is, four kinds of "detectors"
The first nerve cell is called "contrast detector", which can sense the dark front and back edges of moving objects; The second type is called "moving convex edge detector", which has contour reaction to the convex edge of dark objects; The third type is called "edge detector", which is most sensitive to the edges of static and moving objects; The fourth type is called "darkening detector", which reacts as soon as the light intensity decreases. Under the action of these four nerve cells, a complex image can be decomposed into several easily recognizable features and then transmitted to the visual center of the brain. You can see the original complete image after synthesis.
Results According to our visual principle, human beings have successfully developed an electronic frog eye. This kind of electronic frog's eyes can accurately identify objects with specific shapes like real frog's eyes.
After installing electronic frog eyes in radar system, the anti-jamming ability of radar is greatly improved. In particular, it can distinguish between true and false missiles and prevent false confusion.
Since the invention of electric light, life has become more convenient and rich. The electric lamp can only convert a small part of electric energy into visible light, and most of the rest is wasted in the form of heat energy, and the heat rays of the electric lamp are harmful to people's eyes. So, is there a light source that only emits light without heating? Humans have turned their attention to nature again. In nature, many creatures can emit light, such as bacteria, fungi, worms, mollusks, crustaceans, insects and fish, and the light emitted by these animals does not produce heat, so it is also called "cold light". Fireflies are one of many luminous animals. There are about 65,438+0,500 species of fireflies, and their luminescent colors are as follows. The brightness of light is also different. The light emitted by fireflies not only has high luminous efficiency, but also is generally soft, suitable for human eyes, and the light intensity is relatively high. Therefore, biological light is the ideal light for human beings. Scientists found that the luminous device of fireflies is located in the abdomen. This light-emitting device consists of three parts: a light-emitting layer, a transparent layer and a reflective layer. The luminescent layer has thousands of luminescent units. They all contain fluorescein and luciferase. Under the action of luciferase, fluorescein combines with oxidation with water in cells and emits fluorescence. The luminescence of fireflies is essentially a process in which chemical energy is converted into light energy. As early as 1940s, people created fluorescent lamps on the basis of studying fireflies, which greatly changed the lighting source of human beings. In recent years, scientists have isolated pure fluorescein from fireflies for the first time. Later, luciferase was isolated and fluorescein was synthesized artificially by chemical method. Biological light source composed of fluorescein, luciferase, ATP (adenosine triphosphate) and water can be used as a flash lamp in mines filled with explosive gas. Because this light has no power supply and no magnetic field, it can be used to clear magnetic mines under the irradiation of biological light source. Now, people can get cold light similar to biological light by mixing some chemicals.
4. Ask for a composition that imitates bats and radars. Colorful butterflies are in full bloom, such as butterflies with double moon patterns and butterflies with brown veins, especially butterflies with fluorescent wings. The hind wings are sometimes golden, sometimes green and sometimes purple to blue in the sun. Scientists have brought great benefits to military defense by studying the color of butterflies. During World War II, the Germans surrounded Leningrad. Trying to destroy its military targets and other defense facilities with bombers. According to the lack of understanding of camouflage at that time, the Soviet entomologist Schwarzenegger proposed to cover military facilities with butterfly-like camouflage by using the color of butterflies. Therefore, despite the efforts of the Germans, the military base in Leningrad has not been disturbed, laying a solid foundation for winning the final victory. According to the same principle, people later produced camouflage uniforms, which greatly reduced the casualties in the battle.
The beehive is composed of hexagonal small beehives arranged neatly, and the bottom of each small beehive is composed of three identical diamonds. These structures are exactly the same as those accurately calculated by modern mathematicians-rhombic obtuse angle 109.28' and acute angle 70.32'. They are the most material-saving structures, and they are large in capacity and extremely strong, which makes many experts admire them. People imitate their structures and make honeycomb sandwich panels with various materials. It is an ideal material for making space shuttles, spaceships and artificial satellites. Because of its high strength and light weight, it is difficult to conduct sound and heat. Polarizers which are very sensitive to the direction of polarized light are arranged adjacent to each monocular eye of the compound eye of bees, so they can be accurately positioned by the sun. According to this principle, scientists have successfully developed a polarized light navigator, which has been widely used in navigation.
5. Imitation of bat and radar composition (bird) Birds' contribution to human beings is well known. Birds also have a special function, which is to inspire human wisdom and provide principles and blueprints for human beings to explore ideal technical devices or vehicles. It can be said that birds are human teachers in structure, function and communication, and scientists often need to ask birds many modern scientific and technological questions. As a result, many valuable inspirations were obtained from birds, which led to many inventions.
Birds can fly freely in the air, which is so attractive and inspiring to human beings! More than 400 years ago, Italian Leonardo da Vinci designed a flapping-wing plane based on his observation and research on birds, trying to fly with the movement of pedals. Later, after many scientists' experiments, the plane was finally invented in 1903, which realized the ideal that human beings longed for flying into the sky for thousands of years.
Since human beings invented the airplane and flew into the sky, they have been constantly innovating the airplane, and they have quickly surpassed birds in size, load and speed. Nevertheless, in some flying techniques and aircraft structures, man-made aircraft are still not as perfect and exquisite as birds. The tiny hummingbird is a "helicopter" among birds, and it has become the dream of many aircraft designers to make vertical take-off and landing aircraft with hummingbird flight characteristics.
Inspired by the development of pigeon vision, some scientists invented the "electronic pigeon eye"; From the special structure of owl eyes, the "night vision device" was invented; Invented the "electronic eagle eye" by eagle eye; Inspired by woodpeckers' foraging, he invented the "shockproof helmet" ...
6. Imitate the composition in the same style as Bat and Radar 200. Today, under the guidance of the teacher, we learned the text Bat and Radar.
The main content of this text is that scientists got inspiration from bats and invented radar after many experiments and studies. You may ask: bats and radars can be said to be "out of reach". How did they get involved? Well, let me tell you something. You may have seen some bats fly out of caves in search of food at night on TV, but have you ever seen them run into obstacles?
No, do you know what this is about? It turns out that bats have a set of "secret weapons" that can fly safely at night so that they will not collide with obstacles. Scientists learned this answer through experiments and found that bats fly at night not by their eyes, but by their mouths and ears. Because the bat's mouth can emit a sound that humans can't hear, which is called ultrasound. This ultrasonic wave pushes forward like a wave. When the ultrasonic wave meets an obstacle, it is transmitted back to the bat's ear. The bat knew there was an obstacle ahead, so he made a detour. So bats can fly safely in the night sky.
From this text, I understand that the power of nature is really great. Just like a mentor of human beings, it inspires us all the time.
7. The composition of dragonflies and airplanes is modeled after bats and radars. One day, my mother and I went for a walk. On the way, I saw a lovely dragonfly. It can fly straight up and down, which is very interesting. Why can it fly like this?
When I got home, I looked up relevant information. It turns out that when the dragonfly's wings vibrate, there is a terminal at the edge of the wings, which can make the dragonfly fly stably. Scientists found a heavy brown fragment on the edge of the wing to keep the dragonfly flying smoothly.
Scientists observed the flight of dragonflies and invented helicopters. Simply put, they only fly by two pairs of wings. However, if we pay close attention to it, dragonflies can generate local unstable airflow different from the surrounding atmosphere through the vibration of their wings, and use the vortex generated by the airflow to make themselves rise.
Since the helicopter was invented in the last century, there have been countless crashes. All kinds of incidents reflect that there are still potential safety hazards in helicopters or planes. I think we should add dragonfly-like black spots to the helicopter turntable, so that the plane can fly smoothly and there will be no problem from now on.
8. Write a paper modeled after bats and radars. You can write in the summer afternoon. Disturbing flies fly around and sting people everywhere. I was entangled in them, so I grabbed the fly swatter and hit a fly with lightning speed, but it was empty. I was angry and chased a fly for a long time. Finally, I stopped on the ceiling, but unfortunately I couldn't reach it. I could only sit on the stool and watch the flies silently. Looking at it, my mind suddenly turned and a question appeared in my mind: "What flies don't look down from the ceiling?" With this question, I caught some bugs outside, and I was surprised to find that some of them fell off as soon as I put them on, and some stayed on them for a while at most, and then fell off.
The problem has not been solved, but it is getting more and more confused. I asked my mother again with questions, and my mother shook her head helplessly and answered. She asked me to look up all the information about teenagers. So I found the book, and finally everything paid off, and I got the answer. It turns out that this fly has six slender legs, two sharp and hard claws at the end of each leg, and a paw pad covered with fluff at the root of each paw. The claw pad is a bag-like structure with congestion inside and depression below. When the fly stays on the smooth wall or ceiling, a vacuum is generated between the paw pad and the plane, and the fly is firmly adsorbed on the plane. This adsorption force is enough to bear the weight of the fly itself, even if the fly is sucked on the ceiling with its back down, it will not fall down. In addition, the fly's paw pad will secrete a kind of mucus, which will firmly adhere to the object. At this time, my heart is as sweet as honey, because I know another truth and a scientific knowledge.
9. Write a weekly diary 1 imitating the words of bats and radars. Inspiration: In an easy-to-understand and vivid language, this paper tells the story that human beings cracked the secret that bats can fly at night through repeated experiments, and got inspiration from it and installed radar on the plane. After learning this text, I understand that human beings should know nature, observe its characteristics and conduct scientific experiments, so as to create inventions and make contributions to mankind.
2. "Bat and Radar" is the text of Unit 3 1 1 lesson published by People's Education Publishing House. This passage mainly tells that scientists have uncovered the reason why bats can fly at night through repeated experiments, and have been inspired to install radar on the plane to solve the problem of flight safety at night.
One night, bats flew out in search of food. It's strange to suddenly find a plane flying in the air. After some reconnaissance, I learned that radar helped the plane. How does it help planes fly safely at night? The bat decided to visit the radar. The bat said politely, "Brother, may I know your name?" "Hello, my name is Radar", said Radar. How can you fly in the air like me? Bats have questions. Radar said, "It was a great scientist who was inspired by you and invented me." The bat said, "How does an airplane work?" "The radio waves emitted by the plane are like your ultrasonic waves, and the screen of the plane is like your ears," the radar told the bat. "oh! I see. Scientists are really great. " The radar suddenly realized. The bat said, "Goodbye, brother." The radar said, "886!"