Hello everyone, I am a blue whale swimming happily in the sea. Maybe many people think I am a very big fish, but you are wrong. I am not a fish, but a mammal. We whales, like cattle and sheep, breathe with our lungs and are viviparous. Young whales grow up by feeding on the mother whale's milk, which shows that we are mammals. My body is spindle-shaped, almost blue-green, my abdomen is light gray, and there are many white spots on my side. I like nutritious krill best. I can eat more than 2000 Jin in one meal. I usually swim faster, and the speed can reach 8 ~ 12 nautical miles per hour. When I run away, I can swim faster than 30 nautical miles per hour.
Our blue whale is the largest animal in the world. It is generally 24 meters long and weighs more than 150 tons. My father is the biggest blue whale. Its body length can reach 33 meters and its weight exceeds 190 tons. A tongue weighs 4 tons, enough to fill a big truck. Just open its mouth and let a dozen adults in and out freely. Our weight is equivalent to the weight of 32 elephants and more than 300 cows. It takes five train carriages to transport a blue whale.
Our nostrils grow on the top of our heads, and when we exhale, our nostrils will surface. The air ejected from our nostrils forms a water column, and the maximum water column we eject is10 ~15m. If you see that the water column ejected by whales is vertical, thin and high, it is our baleen whale; If the spouted water is inclined, thick and short, it is a toothed whale. Some people can judge our kind and size according to the shape of the water column.
What profound knowledge science is to me; In my opinion, scientists are great people with many inventions. But my mother told me that science is closely related to our lives, and we can't do without science. Therefore, it is very important to popularize natural science and social science knowledge and spread scientific ideas in a way that we can understand, accept and participate. Take washing clothes as an example. I put the dirty clothes in the washing machine. After more than half an hour, clean clothes came out of the washing machine. How amazing!
Curious, after pressing the laundry button of the washing machine, I sat aside and watched the washing machine work quietly. Through the transparent glass door, I saw that the drum of the washing machine kept rotating, driving the clothes in the drum to stir together, and the clothes kept rubbing against each other and between the clothes and the drum wall.
For most stains, water and friction alone can't wash dirty clothes. Washing powder must also be added here. Washing powder is a kind of powdery synthetic detergent, which is often put into the washing machine before washing. The book tells me that there are five ingredients in washing powder: active ingredient, washing aid ingredient, buffer ingredient, synergistic ingredient, dispersant and auxiliary ingredient. Among them, active ingredients play a major role in detergents. The detergent active ingredient is a substance called surfactant, whose function is to weaken the adhesion between stains and clothes. Under the agitation of the washing machine, the stains are separated from the clothes, and the clothes can be washed clean. At this time, I saw many bubbles in the drum of the washing machine. According to my father, it is because many surfactants have strong foaming ability.
Before there was a washing machine, quilts, sheets and clothes were washed by adults by hand, which was often tiring and time-consuming. 19 10, Fisher of the United States successfully trial-produced the world's first electric washing machine in Chicago, marking the beginning of the automation of human housework. With the development of science, washing machines are constantly updated. At my grandmother's house, there is also a semi-automatic washing machine. In that washing machine, the washing bucket and the drying bucket are separated, and the water inlet needs to be controlled, and each step needs a switch. Since I was sensible, I have used automatic pulsator washing machine at home. But my mother thinks the clothes in this washing machine are too worn. At the beginning of school, it was changed to the current drum washing machine. The upgrading of my washing machine shows how fast modern technology is developing!
There's so much learning just in the simple daily chores of washing clothes. The power of science is really everywhere, which makes our life more convenient and comfortable. How I wish I could be a scientist one day.
About Science Expo 3 When it comes to spiders, an ugly image will probably emerge in everyone's mind: eight curved and segmented legs, a spherical abdomen, and a pair of jaws with more or less toxins ... This image often makes people who don't know much about spiders think it is a pest. However, is this the case?
I have observed spiders for a while and found that most spiders are not pests, but they are very beneficial to human beings! They caught a large number of pests in their own unique way. As far as I know, there are two ways to catch insects: the first is the "waiting for the rabbit" method. It first weaves a gossip-shaped sticky net with silk in its belly, and then hides in a corner that is not easy to be found, waiting for the arrival of flying insects. If some unlucky flying insect hits the net, its body will get stuck and can't move. At this time, the spider will quickly climb over, bite the prey and inject "anesthetic" into its body to turn the internal organs of the prey into liquid. And finally? Dinner, of course! I have only seen the second method of catching insects once, and I don't know much about it. This method of catching insects is relatively simple, and there are not many prey caught: it will pounce on its prey like a beast. At the speed of spiders, it is ok to catch some reptiles that can't fly, but what about those flying insects? Will greatly reduce the discount!
In addition, spiders are also excellent meteorologists. On a sunny day, it lazily basks in a large horizontal net. Of course, if it can stick to an insect, it will be an unexpected gain for spiders. On rainy days, spiders will leave the horizontal web and weave a vertical web in another shelter. When you come back after the rain clears, you will find that the horizontal net has been smashed by raindrops, but the vertical net is intact. According to this phenomenon, we can know that it will be a sunny day when spiders make horizontal webs; When spiders spin vertical webs, it will rain.
After this introduction, you should know something about spiders! In fact, my observation is only one-sided, and spiders also have pests. Do you want to know? Please use your head and observe more. If anyone knows more about spiders, please communicate with me to enrich our knowledge!
I live in a big family. There, every family member has a different shape: fat, thin, tall, short, square and round. We all perform our duties and play an important role in human daily life. That's true. I would like to ask, from tape recorders and cameras to pagers and mobile phones, which one is missing our "battery family"? According to the survey, China is a big producer and consumer of dry batteries, with an annual output of 654.38+0.5 billion, ranking first in the world. The consumption is about 7 billion, and every citizen in China consumes 5 dry batteries every year on average! It can be seen that the battery has a wide range of applications and a large consumption. This has further consolidated our important position in life and become one of the widely used commodities worthy of the name.
I am composed of zinc sheet (iron sheet), carbon rod, mercury and sulfuric acid compound, while my brother's battery is mainly lead compound. With the continuous growth of our "battery family" team, waste batteries are also quietly breeding. Because the pollution caused by waste batteries is not as obvious as air, garbage and water pollution, but acts as a "hidden killer", people have never paid attention to it, but although these waste batteries are small, their deterrence cannot be ignored. Will seriously damage the ecological environment, which is determined by our own composition. These substances are sealed inside the battery box during use and will not affect the environment. However, after a long period of mechanical wear and corrosion, heavy metals, acids and bases leaked out and entered the soil or water source, causing environmental pollution and doing certain harm to human health. Data show that waste batteries seriously pollute the soil, which can lead to crop failure. A button cell can pollute 600,000 liters of water, which is equivalent to a person's drinking water for a lifetime; A section of 1 battery buried in the soil can make 1 square meter of land lose its use value. In this way, didn't our "battery family" suffer from "unjust imprisonment" and bear the crime of polluting the environment? Here I want to say a word for my battery compatriots: Our mission of battery life is to contribute to people. When it loses its use value, there is only one "sick" body left. Is this our sin, too? Don't! It is the lack of environmental awareness that makes us the culprit.
At present, people's awareness of environmental protection is still very weak, and they simply don't realize the harm of used batteries. Many people throw it away with domestic garbage, forming a huge pollution source. The main disposal methods of domestic waste in the world are sanitary landfill, incineration and composting, and the mixed waste batteries are also polluted in these three processes. When landfill is used, the heavy metals of waste batteries pollute the water source and soil through infiltration; When incineration is used, waste batteries corrode equipment at high temperature, and some heavy metals volatilize in the fly ash of incinerator, resulting in air pollution. Heavy metals accumulate at the bottom of the incinerator, causing pollution to the generated ash; When using compost, the heavy metal content of waste batteries is high, which leads to the decline of compost quality. In addition, people will adopt the way of reuse. In this way, although the process is easy to master, the recovery rate is only 82%, and the rest of the lead appears in the form of gas and dust. At the same time, sulfur dioxide will enter the air during smelting, causing secondary pollution and directly endangering the health of operators.
We "battery people" hereby appeal: Please use us correctly and let us continue to benefit mankind. In order to reduce the pollution caused by waste batteries, I suggest people recycle them. At present, the treatment methods of waste batteries with a certain scale mainly include heat treatment, wet treatment and vacuum treatment. The method of heat treatment is to grind the waste batteries and then send them to the furnace for heating. At this point, the volatile mercury can be extracted. If the temperature is higher, zinc will evaporate, and iron and manganese will be fused into ferromanganese alloy needed for steelmaking, thus turning waste into treasure. Wet treatment takes advantage of the fact that all kinds of waste batteries except lead batteries are soluble in sulfuric acid, and then various metals are extracted from the solution with the help of ionic resin. The metal obtained by this method is purer than that obtained by heat treatment. Vacuum treatment is to sort out nickel-cadmium batteries from waste batteries, and then extract nickel and manganese from the remaining powder.
In this way, our "battery family" can turn waste into treasure and continue to make contributions to mankind. As a battery, I believe that as long as people enhance their awareness of environmental protection, we will better benefit future generations!
Explanatory articles on popular science often sang such a song when I was 5 years old: "What bird loves to run? What bird loves to sing? What flowers bloom in the water? What flowers look at the sun ... "Among them, the flowers looking at the sun are sunflowers.
Sunflower, also known as sunflower. Why is it called sunflower? Just because the sunflower's disk will turn. Every morning, as soon as the sun comes out, the disc faces the sun. Sunflowers always face the sun from morning till night, no matter where the sun is. This is probably the origin of its name.
So, why is the sunflower tray always facing the sun? I remember when I was a child, I heard a legend that several sons of the sun god took turns to be on duty in the sky. One of the sons, feeling bored in the sky all the time, sneaked to the ground to play. But once he came down from the sky, he couldn't shine. He involuntarily fell to the top of a small tree. Over time, he grew up with the tree and gradually became a sunflower. At this point, he felt that the pie in the sky was still fun and regretted it. I want to go back to the sky, but it is impossible. From then on, he had to look at the Sun brothers who were on duty in turn in the sky.
Every day from morning till night, day after day, my eyes never leave the sun. When I went to middle school and studied botany, I had a scientific understanding of why sunflowers always face the sun. Botanists have found that behind the sunflower disk, there is a substance that has a particularly strong ability to distinguish light. This substance prefers yin to yang. In order to avoid light, the front of the panel constantly changes direction and always follows the sun. From this point of view, sunflower to the sun is not an act of god, but an instinct of life.
Sunflower is panicum miliaceum. In the mature season, he is seven or eight feet tall,-feet tall, or even more than ten feet tall. There is a heavy golden flowerpot with the thickness of a cup on the stem. Against the fat sunflower leaves, it is really fascinating!
Sunflowers, like most plants, are planted in spring and harvested in autumn. Generally, the seeds are sown before and after the awn seeds, and the buds will break out in a few days. At first, the bud only grew two pods, both of which were dark green. The pod is thick, slightly oval, without any edges and corners, and the stem is smooth. When it grew to more than a foot high, its appearance and color changed completely. The previous dark green gradually faded. Each new leaf has a tip, and the whole leaf is peach-shaped. The stems are thick and short hairs grow at the same time. At the top, there is a small bud. At this time, as long as the water and fertilizer are suitable, it will grow up quickly. In June and July, when a person grows to a height, it generally does not grow to a very high place. Leaves as big as a banana fan gradually turn yellow from bottom to top, but only the buds at the top grow up quickly, like a big disk.
The petals around the disk are golden yellow and full of energy, as if guarding the earth. There are countless small yellow flowers in the flower tray, crowded together, but arranged neatly. When the sunflower matures, the big petals and small yellow flowers gradually fall off. Black sunflower seeds are exposed under small yellow flowers.
Sunflower can be enjoyed by people, but it is mainly a cash crop. Sunflower seeds can be eaten or pressed for oil; Sunflower stalks can be used as fences and fuel; Sunflower leaves can also be fertilized. ...
In early autumn, the sun shines on everything, and the sunflowers in the courtyard are facing the sun. Looking at this scene, I remembered myself and our party. ...
Science popularization explains article 6. Recently, there is a new flu called "flu", which has taken away many precious lives. What can be done to prevent "flu"? Say the method first.
First: Wash your hands frequently, whether you eat, go to the toilet or come back from public places. The steps of washing hands are wet, rubbing, washing, holding and wiping. After washing your hands, always be careful not to touch your eyes, nose, mouth and other parts, otherwise the virus will easily invade your body!
Second: take your temperature every day. If your temperature is over 38℃, please don't go to public places or classes. Remember to wear a mask and see a doctor at once.
Third: Try to keep a distance of more than 2 feet when talking to others. Don't talk to classmates and avoid physical contact.
Fourth: If you catch a cold or go to a closed public place, wear a mask. If the mask is contaminated by foreign objects and used for more than 8 hours, it should be discarded and replaced, and remember not to touch the inside of the mask.
Doing this with me every day can not only protect your health, but also keep you away from illness.