Activity objectives:
1. Through activities, students have mastered the knowledge about dinosaurs more deeply, broadened their horizons and corrected their attitude towards science.
2.
Instruct students to collect information needed for research by asking parents, books and the Internet, and cultivate students' practical ability to collect information, process information and draw conclusions from it.
3. Cultivate students' ability of unity and cooperation.
4.
Cultivate students' ability to solve practical problems by using art, information, labor skills and other knowledge comprehensively, train their ability to optimize the combination of knowledge in various disciplines, and strengthen their awareness of solving practical problems by using knowledge comprehensively.
Activity flow:
First, scene import
Show me a dinosaur model.
Teacher: Look, class, what is this?
Student: Dinosaurs.
Teacher: What kind of dinosaur is this? We asked the team leader who specializes in dinosaur species to introduce us.
Student: This is Liang Long, a herbivore. He is a huge dinosaur, with a neck seven or eight meters long and a tail more than ten meters long. His head is thin and small. Although he is big, he is not very heavy, because he is as slender as a snake above the neck.
Teacher: There are many kinds of reptiles and dinosaurs that lived 3.8 billion years ago. They crawled on the ground, swam in the water and flew in the sky, but they, dinosaurs, a creature that ruled the earth for a long time, became extinct in a short time. Scientists are still arguing about the reasons for the extinction of dinosaurs. Let's ask the leader of the dinosaur extinction team to briefly summarize the reasons that scientists have speculated so far.
Student: Scientists speculated on the possibility of extinction of many dinosaurs. Our group collected 16 species, but all the students in our group agreed with the theory of climate quenching. Probably because of crustal movement, the temperature of the earth suddenly cooled a lot more than 3 billion years ago. These huge creatures could not adapt to climate change at once, so they died soon.
Teacher: So dinosaurs died out more than 3 billion years ago. How did scientists infer the age when dinosaurs lived? Next, please tell us about the leader of the dinosaur fossil group.
Student: The dinosaur died out as early as 3 billion years ago, but after several billion years of vicissitudes, its remains and the natural environment in which it lived were truly recorded by fossils. Scientists rely on these real data accumulated for billions of years to infer and restore the situation at that time. The students in our group found many precious pictures of dinosaur fossils in the process of collection and made them into electronic slides.
Teacher: The scene of the era when dinosaurs lived was originally restored by fossils, so what was that era like? We invited the leader of the dinosaur living environment to introduce it.
Student: In the era when dinosaurs lived, there was already a distinction between land, water and air. At that time, the plants on the earth were mainly ferns. Herbivorous dinosaurs are generally huge, can eat very tall leaves, and have relatively few animal species. In order to compete for food, carnivorous dinosaurs generally had sharp teeth and claws. We can play Jurassic Park to restore the earth at that time.
Play the movie.
Second, communicate with each other.
Teacher: So just now, several group leaders made a brief summary of the information we collected this semester. Next, we will ask each group to show each other electronic slides made from the information you collected.
Each group shows slides to each other and gives a brief introduction.
Third, make dinosaur ID cards.
Teacher: According to the knowledge we have just mastered, I asked my classmates to take a dinosaur as an example and make an ID card for it. The ID card should have the photos, names and living habits of dinosaurs. Make this ID card as detailed and beautiful as possible, and then give it to your classmates or teachers for them to learn.
Students use art knowledge and labor skills to make dinosaur ID cards and give them to each other.
Fourth, the expansion package
Open an independent class meeting with our dinosaur knowledge, publish a blackboard newspaper with a special issue of dinosaurs, and decorate a talent corner with a good classmate's dinosaur ID card.
Verb (abbreviation of verb) abstract
Teacher: Dinosaurs are extinct. Scientists have made a lot of scientific speculations based on the dinosaur fossils we collected, but the fascination of dinosaurs with human beings has not been completely solved. What kind of creature is a dinosaur? What impact does it have on our current creatures? How on earth did it become extinct? So many problems are still waiting for us to solve. The teacher really hopes that one of our classmates can solve such a mystery for us in the future.
Science and technology composition of fourth grade pupils 1. Environmental essay competition
In order to carry forward ecological culture, actively carry out green school creation activities, comprehensively promote the construction of an ecological province, and guide and cultivate students to establish a good awareness of environmental protection, the Provincial Department of Education and the Provincial Environmental Protection Bureau will jointly hold environmental essay writing activities for primary and secondary school students in the province. The relevant matters are hereby notified as follows:
1. Activity theme: green ecology, environmental protection and circular economy.
2. Contents and requirements of the paper:
(1), actively organize students to carry out research and investigation activities on ecological protection and environmental education, and form investigation reports or small papers through environmental protection practice activities. Papers formed in the past year can participate in the evaluation.
(2) Starting from protecting every environment around us, we should integrate into life, learn and observe things around us. For example, study the changes of the air and river water people breathe every day, the classification of garbage, whether the plastic bags of fast food boxes are environmentally friendly, send fewer New Year cards, save paper and energy, and so on. , focusing on the resource saving and recycling of various wastes, as well as the problems and solutions encountered in daily environmental protection practice activities, including environmental protection inventions, suggestions and environmental protection investigation reports.
Second, biological and environmental science practice activities:
Requirements: The practical activities of biology and environmental science should be designed by students themselves, and the achievements of others should not be copied. There should be a relatively complete implementation process and complete original materials (photos, etc.). ), actual experience, etc.
(Example of subtitle name)
1. Study on Growth Correlation of Cinnamomum camphora
2. I help rape see a doctor.
3. Investigation on frog protection practice in our city
4. Investigation on the Survival Status of Street Trees
5. Investigation on the pollution and harm of waste batteries
6. Explore the secret of magnetic weakening of magnets
7. Investigation report and analysis of vegetable market environment
8. Research on lunch garbage.
9. Preliminary study on domestication practice of wild ducks
10. Investigation report on the surrounding environment of the school
The fourth-grade students in primary school are in urgent need of shorter scientific and technological compositions. Do this homework by yourself. Don't form bad habits from childhood.
Why don't ants get lost?
An unremarkable ant, I believe everyone is familiar with it. Then who can really understand ants? Another question came to my mind: Why don't ants get lost?
With this question, I looked up some books and read some information on the computer, and then I understood that ants leave some smells along the way after they leave the nest for their destination, and then return to the nest. Touch each other with tentacles and notify other ants. Scientists once did an experiment. Scientists first identify an ant and vigorously clean up the place where he reaches his destination along the way. When the ant came back, it suddenly stopped at the place where the smell was wiped off. Looking for something while walking in circles. People come to the conclusion that ants can tell their directions by their sense of smell.
But isn't that true in real life? I did an experiment to confirm this conclusion. I found a long stick, sprinkled some rice grains and put it around the ant nest. I hid around the bird's nest. Soon, the ants came out of the nest. It climbed up the stick and soon reached the place where the rice was enlarged. When it moved rice in a hurry, I quietly broke the back end of the stick a little and immediately hid to one side. The ant walked home happily with the result. When it reached the broken place, it immediately stopped, circled in place and used it. " And this happiness is temporary, I'm afraid it's just an accident. The teacher said that science can't avoid chance! So, I repeated the experiment just now for three times, and I was relieved. Finally solved the mystery!
Why don't ants get lost? Because ants know their direction through their sense of smell. Through my efforts, this answer has been confirmed. This time, I laid a solid foundation for understanding ants.
Middle School Students' Scientific Composition Coin on the Water
While studying the ups and downs of objects, a classmate came across an interesting phenomenon: when putting a plastic ruler vertically (or horizontally) on the water, he found that the ruler sank rapidly; When he laid the ruler flat on the water, he found the ruler floating on the water.
When the ruler is placed vertically (or sideways) on the water surface, the ruler sinks because the buoyancy of the ruler is less than its own gravity; Then why does the ruler float on the water when it is flat? According to the ups and downs of an object, the buoyancy of the object is equal to gravity when it floats. Aren't the two contradictory? What is the crux of the problem?
In the chapter "Properties of Solids and Liquids" in the first volume of senior high school physics textbook, there is a small experiment: students are required to put sewing needles on the water with cotton paper. When cotton paper sinks in water, observe the phenomenon and explain the reasons. Many students think that the sewing needle floats on the water because of the surface tension of liquid, and the needle can float on the water because of the balance of gravity, buoyancy and surface tension of liquid.
So let's first understand the surface tension of liquid.
What is the surface tension of liquid?
When the molecules near the liquid surface move outward from the equilibrium position, the external air and vapor molecules have little repulsive force on it. Did not play an important role. It is only attracted by internal molecules, so the force to restore it to its equilibrium position is not as great as that in liquid, which makes the vibration amplitude of surface molecules larger than that in liquid, and some molecules with large kinetic energy may rush out of the suction range and become vapor molecules, resulting in the sparse distribution of surface molecules than in liquid, and the distance between molecules is relatively large (r >: R0), precisely because of the sparse distribution of molecules inside the liquid surface and the molecular spacing r >; R0, intermolecular attraction prevails, leading to surface tension of liquid. Therefore, the essence of liquid surface tension is the resultant force of intermolecular interaction, which points to the inside of the liquid. It can be seen that the force that holds up the coin cannot be the surface tension of the liquid. Then let's look at buoyancy again.
Let's do an experiment first:
Put a piece of filter paper on the surface of the beaker filled with water, and put a dime on the filter paper. After the filter paper was soaked and sank, it was found that the coin was still floating on the water. Pay attention to the coins and you will find that the water surface is sunken downwards, and the coins are not immersed in the water, but floating on the water surface. It can be seen that the coin is not affected by buoyancy at this time. What is the balance between the force and gravity that makes coins float on the water?
As can be seen from the previous experimental phenomena, the water surface is depressed and deformed downward, thus producing an elastic force-supporting force opposite to the deformation direction, which is like putting an object on an inflated balloon, and the balloon is deformed (depressed downward) due to the gravity of the object, resulting in a vertical supporting force. It is this supporting force, which is equal to and opposite to gravity, that makes coins float on the water. In the above experiment, the plastic ruler floating on the water is the same as the sewing needle. )
Why do rulers, sewing needles and coins sink horizontally or vertically? Let's take coins as an example. When placed horizontally or vertically, the stress area of the liquid surface is very small, the pressure is very high, and the pressure effect is remarkable; This is the same as wearing high-heeled shoes and stepping on the sand. The heel will sink into the sand and the coin will sink into the water, thus breaking the elastic deformation of the water surface and making the support of the water meter disappear. At this time, the coin is only affected by buoyancy and gravity, and because gravity is greater than buoyancy, the coin will soon sink to the bottom of the water. When the coin is laid flat, the pressure on the water surface is very small, so the above phenomenon will not occur, and the coin will float on the water surface to maintain balance. In nature, there are many similar phenomena. Some small insects can run around or stay on the water without going into the water, and the same is true.
Quickly ask for a short essay on "Primary School Students' Scientific and Technological Innovation". My mother once told me such a riddle: "Zhuge Liang is in Nanyang, sitting firmly in the army account." "Arrange the eight diagrams and catch the flying generals." This myth tells us that spiders only eat living things, doesn't it eat dead things? This aroused my interest and I did the experiment.
I caught a little spider from the corner and put it in a box (with holes around it and glass on it for easy observation). Before the spider could weave a web, I picked up a dead bug and a dead fly and put them in front of the spider. The spider ignored them, then hit the box with her hand, and the spider crawled in other directions.
In order to find out whether spiders eat dead flies completely, the next day, I came to the box to observe and saw that dead insects and dead flies were still in their original places, but there was a net in the corner of the box, and the spider was lying quietly on the net. At this time, I thought: Is it because there is no net that the dead flies and insects didn't eat it yesterday? So I picked up the dead fly and gently put it on the net, but the spider still didn't move. Then, I gently touched the edge of the net with my pen. Gee, the spider seems to have a reaction and started to climb in a trembling direction. I took the pen back and the net stopped shaking. The signal was interrupted and stopped. Soon, the spider climbed to the center of the web again. I touched the dead fly's body on the net with the pen tip again, and the net began to vibrate, and spiders began to crawl here. I took back the nib again and the spider stopped. Like last time, after a while, the spider climbed to the center of the web again. Oh! I finally understand that spiders feel by the vibration of their webs and prey by weaving them. So, I recorded the experimental results.
In order to prove that spiders feel through the vibration of their webs, I did another experiment. Put the pen tip on the dead fly on the net and vibrate for a long time. The vibration of the web is getting bigger and bigger, and the spider seems to feel stronger and stronger. Spiders will come in a hurry. When a spider meets a fly, I will take back the pen tip, only to see that the spider's tail will soon spit out sticky silk to tie the fly, and then look at the spider's back, as if sucking the fly. Soon, there was a complete empty shell left on the Internet. This experiment proves that spiders eat moving insects.
Our secret group went to the library and bookstore to consult a lot of books about spiders. Among them, General Zoology wrote that spiders are carnivores, and their food is mostly insects or other arthropods. But the mouth has no upper jaw, so you don't swallow solid food directly, but suck it slowly. When insects and other animals come into contact with the net, they will struggle desperately on the net to make the net silk vibrate, so that spiders will find it soon. Spiders will crawl along the longitudinal silk to their prey, wrap the prey with spider silk and fix it on the net. First, the venom secreted by poisonous glands in claws is injected into the captured prey to kill it, then the digestive enzyme secreted by midgut is injected into the captured tissue torn by claws, which is quickly decomposed into juice, then inhaled into digestive tract, and finally eaten the remaining body shell. These fully prove that flying insects make the spider's web vibrate, and the web vibration will make it feel, and the spider will catch its prey if it feels. So it is confirmed that spiders only eat live animals, not dead insects.
Model essay 1: Why is the trunk round?
In the process of observing nature, I happened to find that the shape of the trunk is almost round-an empty cone. Why is the trunk conical? What are the benefits of a conical trunk? In order to discuss these problems, I made more in-depth observation and analysis. With the help of my tutor, I consulted relevant materials and learned that the stems of plants have the functions of supporting plants and transporting water and other nutrients. The stems of trees are mainly composed of vascular bundles. The supporting function of stem is mainly borne by wood fibers in xylem. Although the stems of woody plants will become thicker year by year, in a certain time range, the number of woody fibers in the stems is certain, that is, the cross-sectional area of the stems is certain. Then, based on the assumption that the cross section of the trunk grows into different shapes, we design experiments to explore the reasons and advantages of conical trunk. Through experiments, we find that when the cross-sectional area and length of (1) are fixed, the vertical supporting force of triangular columnar objects is the largest and the lateral bearing capacity is the smallest; The vertical supporting force of cylindrical objects is not as good as that of triangular cylindrical objects, but the lateral bearing capacity is the largest; (2) For trunks with the same mass and different shapes, the short conical trunk bears the largest wind force; (3) Wind is a natural phenomenon, which affects the cross-sectional shape and height of trees. The approximate cone-shaped trunk has a low center of gravity, and the huge root system is connected with the earth, so the center of gravity drops lower and the stability is greater; (4) The cross section of the trunk is round, which can reduce the damage, has stronger mechanical strength and can resist the wind attack. At the same time, under the action of the wind, the bending degree of the trunk is similar everywhere. No matter which direction the wind blows, the resistance of the trunk is similar, and the trunk is not easy to be damaged. The above experiments reflect the laws of nature, and nature enlightens us: (1) A columnar object with a triangular cross section has the greatest longitudinal supporting force, and its shape can be used in buildings, such as angle steel; (2) A circular object with a circular cross section has the largest lateral bearing capacity, and similar building materials can be found everywhere, such as TV towers and telephone poles. In the process of my observation, experiment and analysis, I gradually explained and revealed the mystery of conical trunk, increased my knowledge and applied what I have learned, which not only consolidated my knowledge and improved my interest in learning, but also preliminarily learned the scientific observation and analysis methods.
Fan Wen 2: Why do leather shoes shine brighter and brighter?
Every Sunday, I always finish the task of shoeshine given to me by my mother. Tell you, this is the source of my pocket money for a week! After getting the leather shoes covered with dust, I first wipe off the dust on the vamp, then apply shoe polish and wipe them carefully, and the leather shoes will become bright and beautiful. But why is this? I found two pairs of old and new leather shoes of the same brand and style for comparative observation. I first touched the uppers of two pairs of leather shoes and found that the surface of the new shoes was much smoother than the old ones. Old leather shoes are coated with shoe polish. After careful polishing, it shines a lot, but it is still not as good as new leather shoes. Is there a relationship between the brightness of leather shoes and the smoothness of uppers? I brought a pair of old leather shoes that were not polished, and the uppers were uneven under the magnifying glass. Then, I circled two rough areas A and B on the leather shoes. Carefully wipe area A with shoe polish, and area B without shoe polish as a blank control. I found that the surface of area A is obviously smoother after wiping, and it is more shiny than area B when placed in the sun. Why is there such a big difference between them? I think the teacher once said in physics class that the wall of the theater is uneven, so that most of the sound can be absorbed and the audience will not be disturbed by the echo. Similarly, light will be reflected on the surface of any object. If the plane is uneven, light will scatter in all directions. If this plane is smooth, then we can see the reflected light in a certain direction. The surface of leather shoes is not absolutely smooth. If it is an old leather shoe, its surface is of course more uneven and can't reflect light in a certain direction, so it looks dull. There are some small particles in shoe polish, which can just be filled into the pits on the surface of leather shoes when shining shoes. If you wipe it with a cloth again, the shoe polish will be more uniform, the surface of leather shoes will become smooth and flat, and the reflective ability will be strengthened. Through the experiment, I finally know the secret of shoes getting brighter and brighter!
Model essay 3: What effect does vinegar have on flowers?
Vinegar is a common condiment in life, while flowers can purify the ecological environment and beautify our life. Have you ever thought about the relationship between vinegar and flowers? We explored the subject with curiosity. According to people who have rich experience in planting flowers, applying some vinegar on potted flowers can improve the growth of potted flowers and increase flowers, which are bright and leafy. We soon confirmed this in the experiment. Do different concentrations of vinegar have different effects on flowers? This is the second stage of our experiment. We select four pots of gypsophila paniculata, primrose and Chinese rose with the same growth and divide them into four groups. Each group (three pots) has three kinds of flowers, which are numbered and labeled respectively. At the same time, we prepared edible white vinegar into three solutions with different concentrations: 1% (pH 2~3), 0.0 1% (pH ≈4) and 0.000 1% (pH ≈6), and sprayed vinegar on three groups of potted flowers once a day, while the fourth group did not. Observe and record the growth of flowers every five days. The results of this experiment are as follows: spraying low concentration vinegar (pH ≈6) has no obvious effect on these flowers; The flowers sprayed with moderate concentration of vinegar (pH ≈4) are obviously better than other groups, with more buds, earlier flowering, richer colors and longer flowering period. Spraying high concentration vinegar with pH value of 2-3 will make the flowers wither prematurely. Through this experiment, we can tell you that spraying vinegar properly when planting flowers can make flowers grow better. But to master the concentration of vinegar, excessive acetic acid will harm flowers.
Ask for a short essay on science and technology, not too long, just 400 to 500 words. match
Doing experiments is my favorite form of entertainment. I often go to the bookstore to read some books about doing experiments, and then go home to do experiments from memory.
On this day, I came to the bookstore again and suddenly found a strange experiment: match dancing. Can you believe that naked matches can dance in the water? I can't believe it. I came home with a curious heart, ready to solve my doubts by doing experiments.
Back home, as usual, I started the experiment from memory.
I brought a basin of water, a match and a bottle of "all-purpose glue". I applied a thick layer of "all-purpose glue" to the match head, and then carefully put the match into the clear water. After waiting for a while, I didn't see any response. I calmed down and waited patiently. A few minutes passed. "Miracle" really appeared! I saw matches standing upright in the water and dancing with the swing. However, in less than half a minute, the match floated on the water again. A few minutes later, the match began to dance again. After seven or eight times, the match never moved again.
What magical power drives matches to "dance"? My mind is full of doubts and I can't figure it out. Finally, my silent teacher, the computer, helped me. It turns out that when the "all-purpose glue" comes into contact with the phosphorus on the match head, it will produce a substance. The more this substance accumulates, the more it will make the match stand upright. When this substance volatilizes, matches are driven to dance. After a while, the outermost substance of the matchhead evaporated and the match did not move. During this time, the generated substances gather again, and the matches "dance" again until the reaction between the all-purpose glue and phosphorus is over.
At this moment, I suddenly realized: Ah! Matches can dance, so that's it.
I want an English composition for primary school students, the topic is my family's composition, not too long nor too short, please! There are four people in my family, my parents, my brother and me. My family is very good. I'm really happy.
My brother is shy and funny. He is good at sports and plays volleyball very well. But he hates studying and his grades are not good. He likes telling jokes. He always plays jokes on his friends and my family and always makes us laugh.
My father is a doctor. He works in a hospital in Sanya. He doesn't like watching TV, but he likes reading newspapers and reads them every night.
My mother is a waiter. She works in a restaurant. She has good habits. She likes eating vegetables and drinking milk every day. But I don't like milk. It's terrible. She likes watching Beijing opera in her spare time. She said it would be good for her to stay young, which would make her relax.
My family always does what is best for me. They are always on my side.
I love everyone in my family. I love my warm home.
There are four people in my family: my parents, my brother and me. My family is great and I am very happy.
My brother is shy and funny. He is very good at sports, especially volleyball. But he doesn't like studying and his grades are not good. He likes telling jokes, often jokes with friends and family, and always makes us laugh.
My father is a doctor. He works in a hospital in Sanya. He doesn't like watching TV, but he likes reading newspapers very much and always stays up late.
My mother is a waiter. She works in a restaurant. She has good habits. She likes eating vegetables and drinking milk every day, but I don't like milk. It's terrible. In her spare time, she likes watching Beijing Opera. She says it helps her stay young and relaxed.
My family always does everything that is good for me. They are always on my side.
I like every member of my family, and I like this warm home.
______________ -
Pupils? Then it's simpler:
my family
There are five people in my family. My mother, my father, my grandparents and me. There is a lovely cat in my house. My mother is a teacher and my father is a reporter. My grandfather likes hiking and my grandmother likes watching TV. We all have a hobby-reading travel books.
There are five people in my family. My mother, my father, my grandparents and me. There is a lovely kitten in my home. My mother is a teacher and my father is a reporter. My grandfather likes hiking and my grandmother likes watching TV. We all have the same hobby-reading travel books.
I want an English composition for primary school students, the topic is my favorite composition, not too long nor too short, please! My hobby
I have many hobbies, such as reading, skating and watching TV. But reading is my favorite hobby. I like reading for three reasons. First of all, books introduced me to a new world, which is rich and colorful, without time and space restrictions. Through reading, I can trace back. To ancient Egypt, the cradle of human civilization. It can take me to America, a charming place that I have been longing to go. Secondly, reading can let me see a new vision and improve myself. In the past few years, most of my knowledge has been obtained from books. I learned from many people their views on science, politics, life and society. Third, reading has built a bridge between my dream and my goal. In order to succeed in my future career, I must keep reading, thinking and practicing. Reading has become a part of my life. I spend some time reading books, newspapers and magazines every day. At night, I can hardly go steep without a novel in hand.
My hobby
I like painting. It really brings me happiness.
When I was a child, I was keen on drawing lines and curves of animals and scenes on paper. It can really show people beauty and express my feelings. Then I took a course so that I could get close to it and observe it well. But at that time, I was just having fun.
Several years passed, and I entered a stressful learning period. I find it a good way to relax. It no longer plays an unimportant role in my life, but has become my friend.
From then on, I felt that I was a good person in my heart, and I could tell the truth and live happily. This is my hobby, not only a hobby, but also a true friend.