Please give me some popular science compositions. I want to refer to them and write another article.
1、
Today is Tuesday, and I am very happy. Because today we can visit the sewage treatment plant, Xintiandi Park, Wu High-tech Museum and the Poplar Flower Base. After the morning reading class, we set off.
We went to the sewage treatment plant by bus first. After getting off the bus, we lined up neatly and walked into the sewage treatment plant. After walking for a while, I smelled some bad smells. I continued to walk inside, and the smell became stronger and stronger. I covered my nose with my hand and walked. I see a big green disc. We stepped on the disc and walked along a path. I looked down. Wow! It's all black water down there! I think: this must be the reason why people pollute the environment too seriously. If the garbage is thrown into the water, it will rot and deteriorate in the water, and the water will become so black. Walking on, I saw a round pool. When I took a closer look, the water here became cleaner. After a long walk, I saw the second round pool. The water in the swimming pool becomes clear and can be used by us again!
After visiting the sewage treatment plant, we came to Xintiandi Park. There are many interesting projects here. I played four projects, including treading on thin ice and Crazy Mouse, and each project made me feel fresh and exciting. At noon, we came to the fountain pool, and just sat down, the fountain emerged from the water, some like two long dragons, some like proud peacocks, and some ... really beautiful!
After a short rest after lunch, we came to the Wushu High-tech Museum again. There are many animal specimens here, including those flying in the sky, those swimming in the water and those running on the ground. There are still many things we don't know, and I must understand them when I grow up.
Finally, we came to the poplar flower base. The flowers here are in full bloom, including chrysanthemums, roses and tulips ... what a sea of flowers; The trees and grass here are green. The teacher said that seeing more green is good for my eyes, so I stared at the green in front of me as if to make my vision return to normal at once. After a tour of Qingyang Flower Base, we went back to school by bus.
What an interesting day! After going to so many places, we also learned a lot of scientific knowledge and environmental protection knowledge that we can't usually learn in class, which benefited us a lot. I really hope there will be more such activities.
2、
At the end of last year, near the festival, my mother bought me a daffodil. I was so happy that I put it in the basin as my mother said, then poured clean water into it and put some pebbles in the basin.
I change the water once every three or four days. My mother said that the Spring Festival would be held and the flowers would be particularly fragrant. A few days later, daffodils sprouted, much like onion seedlings. About a month later, several buds grew out of the green leaves.
The Spring Festival is coming, and those buds haven't bloomed yet. It may not know how anxious I am to see the flowers! After the Spring Festival, not only did it not bloom, but the buds withered. Mother told me that it was dead and hopeless. I'm so sad! I am determined to find out the cause of its death. So, I went to the computer to find information. It turns out that the growth of daffodils needs sunlight, and the suitable temperature is 12℃-16℃. If the water temperature is too low, daffodils will only grow leaves and will not bloom, or even die. During that time, the south was hit by a once-in-a-century heavy snow, and the temperature in our place dropped to 0 degrees Celsius, which lasted for more than ten days. I didn't take any heat preservation measures to protect the flower buds, which led to the death of daffodils. I just froze to death because of my mistake, and I regret it.
I see, it takes knowledge to raise daffodils! Although daffodils don't need any flower fertilizer, they only need water. But in order to make daffodils grow strong, they should be taken to the balcony to bask in the sun during the day. If you want to postpone the flowering period, you can reduce the water temperature, not too low, 10 degrees Celsius is appropriate. In addition, if you can't see the full flower buds before the festival 10, you can use water heating to promote the flowers, and the water temperature should be close to the body temperature. With this experience of failure, I believe that a fragrant "Ling Boxian" will be raised by the end of this year.
The May Day holiday is over, and the students are taking advantage of this holiday to travel and play! I am no exception. But many people don't pay attention to the habit of washing their hands before and after meals. I paid attention. Once, when I was washing my hands. Suddenly a question popped up in my mind. "Because washing hands with soap takes a few seconds to foam, it takes a while to foam a lot. I'm used to rubbing with water and soap, and generally there won't be too many bubbles. But both methods will hinder the feel. It is generally believed that hands are clean if they are not smooth to the touch. So I want to wash my hands with soap. Do I have to rub bubbles? Is it related to surface tension? I thought about it, "just like cutting steel with a cutting machine will produce sparks." "The friction between hands and some substance in soap will produce foam." When I came back, I asked my father again. My father told me, "Because there is a substance in soap that bubbles when it meets water." But I think my father's explanation is not reliable, so I went to the library again and consulted relevant books. Finally, I knew: "Soap is a surfactant, and surfactants also include washing products and other preparations such as table lotion, soap (similar to soap) and washing powder. Their function is to make the surface tension of liquid (usually water) smaller, and the macro performance is the appearance of bubbles. And why is it easy to foam with soap? Because in the natural state, the surface tension of water is large, which makes the water film unable to form a spherical shape, and the surfactant reduces the surface tension of the liquid, so it is possible to form a spherical water film. The spherical water film will not be torn by such a small surface tension in a certain period of time, so a large number of bubbles that are difficult to form in the natural state will be generated after soaping. " It seems that Shu is really a good teacher!