Chief Reporter Wu Ji of Shenzhen Business Daily • Reading Client Correspondent Zheng Zeyun Hai Jinting Su Xin
Why do seeds germinate, why do plants bloom, and every question of a child hides the exploration and desire for nature. In April, let us walk into the science classroom of Hongling Experimental Primary School, feed the silkworm babies with the children, understand the silkworm culture and silk civilization, and understand life in the life process of silkworms; plant impatiens together and experience the joy of harvesting fruits; explore "heat" together, observe and think about some thermal phenomena related to the degree of cold and heat of objects, understand the diversity of organisms in the population, study biodiversity, explore how to better protect biodiversity, and feel the beauty of the earth's homeland.
Third grade: The life of a silkworm baby
Spring is bright, and it is a good time to raise silkworms. After learning the lesson "Welcoming the Arrival of Silkworm Babies", the children knew the precautions for feeding silkworm babies. After class, the students claimed the silkworm eggs that were about to hatch from the science teacher and started the journey of silkworm raising with joy.
The children prepared a clean and ventilated small house for the silkworm babies to observe the growth of the silkworm babies every day. Finally, a week later, the baby silkworm burrowed out the silkworm eggs, and the purple-black silkworm eggs turned white.
The newly hatched silkworm baby is very small, only 3 mm, black and black, like a small ant, so it is also called "ant silkworm".
Silkworm babies eat mulberry leaves day and night, and within a few days, they begin to molt. The baby silkworm that has finished shedding its skin is larger and eats more. After several molts, the baby silkworm is getting whiter and cuter. After almost a month of feeding, the silkworm baby grew into a 5-star silkworm, with an amazing amount of food, and it rustled when eating mulberry leaves.
After another week or so, the silkworm baby suddenly stopped eating, was hungry and thin, and its body became smaller, yellow and shiny, and when placed in the light, the whole body became transparent. Silkworm babies need to spend a certain amount of time to find a suitable place to form a cocoon, after finding, the silkworm baby head and chest are held high, the head is shaken in a figure 8 or S-shape, the mouth spits silk, and begins to spin silk cocoons. Silkworm babies really love to be clean, and they will also discharge their body water and feces out of the cocoon before forming a cocoon.
After two days and nights of spinning silk and forming cocoons, it was finally completed! White, pink, orange, green, and all kinds of cocoons appeared in front of the children's eyes.
At this time, what happened to the silkworm baby in the cocoon? The teacher gently cut the silkworm cocoon and poured out the silkworm baby, and the silkworm baby changed into a new look! The silkworm baby turned into a brown silkworm chrysalis! There was also a small black object in the silkworm cocoon, which was the skin of the silkworm shed.
The silkworm chrysalis is motionless, is it still alive? The children gently touched it with tweezers, and the silkworm chrysalis twisted its little waist and moved, which was really interesting! It turned out that it was just sleeping.
After more than ten days, the silkworm experienced the sixth molt and turned into a silkworm moth and came out! The silkworm moth and the silkworm baby are not at all like it!
The life of a silkworm is very short, only five or six days. The children edited the records of silkworm raising into videos, and some drew beautiful hand-copied newspapers to record the short life of silkworms.
The male moth flapps his wings in search of the female moth to mate his tail. They take a long time to copulate! After the female moth mates, they begin to lay eggs, and the newly laid eggs are pale yellow. After the female moth lays eggs, it will attract the male moth to mate again, and so on until the energy is exhausted and dies.
The life of a silkworm is very short, only about 56 days. The children edited the records of silkworm raising into videos, and some drew beautiful hand-copied newspapers.
In addition to feeding and observing silkworms, the children also experienced some interesting activities, such as silk reeling, making silk fans, and making silk quilts.
The silk activity expanded the students' interest, increased their knowledge, and exercised their hands-on ability.
Fourth Grade: Big World in Small Seeds
After learning the lesson "New Life is Born in Seeds", the children learned that green flowering plants almost all start new life from seeds, and each small seed is pregnant with the secret of growth. After learning about the structure of the seeds, at the end of February, the students received the impatiens seeds from the teacher as a group and sowed the seeds with great anticipation.
The children take care of them carefully, water them on time, observe them, and look forward to new changes in the seeds every day. Finally, after ten days, the seeds germinated two thick cotyledons, like two little hands to greet the children.
After more than a month, the children's impatiens have quietly changed, the impatiens have grown real leaves, shed cotyledons, grow taller and taller, more and more lush, let's take a look!
During this time, there are already groups of impatiens quietly blooming beautiful flowers!
The growth of impatiens continues, and through this scientific practice activity, the children have experienced the hardships of labor, reaped the fruits of labor, and cultivated scientific interest and scientific qualities of tenacity and willingness to explore. At the same time, the children experienced the whole process of the life cycle of plants and gained a deeper understanding of the meaning of life. The children planted impatiens in the soil, and the seeds of "living with heart, loving life, and participating in the construction of ecological civilization" are planted in their hearts.
Grade 5: How heat is transmitted
The more common things in life, the easier it is to be overlooked. For example, when you hold a cup of hot tea in both hands, your hands will slowly get warmer, and if you hold a piece of ice, your hands will get colder and colder. We must have all had this experience, but have you ever thought about what this is all about? When we talk about heat, it's actually a kind of energy, and it's easy to "run around," that is, heat transfer takes place. How is heat transferred? Which materials are made of good heat transfer performance? With curiosity and love, with questions and thoughts, the students started a journey of exploration of heat.
Cold milk that has just been taken out of the refrigerator and put it in hot water will turn into hot milk. How does hot water make cold milk hot? Children study the temperature changes between the test tube and the beaker when they come into contact with the hot water to explore the transfer and equilibrium of heat.
In life, it is desirable to have heat transferred quickly to another object, such as when cooking in a pot. However, in other cases, we prefer it to be better to transfer the heat slowly, such as when holding the handle of a pot. So is there any difference in heat transfer between objects made of different materials? By comparing the thermal conductivity of wood, plastic, and metal, the students learned that objects made of different materials have different heat transfer skills. By comparing the heat transfer performance of copper wire, aluminum wire and iron wire, the students learned that even if it is a good conductor of heat such as metal, the heat transfer performance of different metals is different.
Grade 6: Colorful pictures of protecting the earth
Earth is amazing, it is the only planet known to be suitable for human survival. We humans live on Earth together with other animals and plants. Every living thing on Earth is unique, and together they make up biodiversity, including species diversity, genetic diversity, and ecosystem diversity. Biodiversity is like a palette of nature, giving the earth its unique colors and vitality to life. From the birds of the rainforest to the mystical creatures of the depths of the sea, from the snow leopard in the majestic mountains to the sparrows in the skyscrapers, every creature is an indispensable part of this picture. However, due to the impact of human activities, many organisms are facing threats to their survival, and it is imperative to protect biodiversity!
Starting with the organisms around students' lives, students will be guided to further understand the diversity of biological species on the earth and the similarities (heredity) and differences (variations) of different individuals in the population. Heredity and variation are universal phenomena in the living world and are the basis of biological evolution. Diversity, survival, and extinction are all the results of biological evolution. Biodiversity is studied in order to better protect biodiversity. By studying the relationship between biodiversity and us, we will further explore how to better protect biodiversity.
Behind every small activity of scientific practice, every exploration of nature, there is more knowledge. Chen Heqin, a well-known educator, said: "Nature and the big society are living teaching materials. "There is no better teacher in the world than nature, who unreservedly presents everything to children to see, to hear, to touch, to discover, to explore......