Mathematics knowledge fourth grade book II People's Education Edition

1. Little knowledge of water, grade four

Little knowledge of water, grade four, 1. Composition on water in the fourth grade of primary school

Water is a common thing, which can be seen anytime and anywhere in our daily life. However, water is closely related to us and is what we need most.

Water is the source of life. We should drink water every day to maintain normal physical needs. Water can be used not only for drinking, bathing, washing clothes, washing face, watering flowers and raising seedlings, but also as an essential component of various drinks, wines, foods and medicines. Seemingly ordinary water is widely used in industry, agriculture and wine-making industry.

Without water, people will not survive, animals and plants will die, and the earth will become lifeless and energetic. ...

Water is very important to us, but sometimes it will bring us unexpected harm and loss. This summer, I saw on TV that many students drowned while swimming in the water. I was very sad. In some places, heavy rains caused floods, houses were flooded, and things at home were washed away by floods, which brought great losses to people and made people afraid and sad!

This is what I know about water. In the future, I must study hard and learn more about water, so that water can benefit us!

2. Water composition in the fourth grade of primary school

Water is a common thing, which can be seen anytime and anywhere in our daily life.

However, water is closely related to us and is what we need most. Water is the source of life. We should drink water every day to maintain normal physical needs.

Water can be used not only for drinking, bathing, washing clothes, washing face, watering flowers and raising seedlings, but also as an essential component of various drinks, wines, foods and medicines. Seemingly ordinary water is widely used in industry, agriculture and wine-making industry.

But now, we abuse the water source, and the wastewater discharged from factories has polluted the water source. Without water, people will not survive, animals and plants will die, and the earth will become lifeless and energetic ... water is very important to us, but sometimes it will bring us unexpected injuries and losses.

This summer, I saw on TV that many students drowned while swimming in the water. I was very sad. In some places, heavy rains caused floods, houses were flooded, and things at home were washed away by floods, which brought great losses to people and made people afraid and sad! In the future, I must study hard and learn more about water so that water can benefit us.

3. The voice of nature in the fourth grade of primary school, 400 words about running water.

If water is the source of all things, then running water is the spirit of all things, fresh and beautiful.

Running water, a symbol of nobility and chastity since ancient times, has washed away the dust in the world, washed it clean and left happily, with a slight taste of "entering the ocean and never coming back", although it is not as magnificent as the Yellow River and the Yangtze River, nor as quiet and gentle as the water in the West Lake. But they are lively and naughty, and they are not lacking in vitality, just like a bird that just escaped from a birdcage. Enjoy, be happy and be free.

In their seemingly casual running, they always maintained a clear and firm goal-the sea. They don't forget their mission, grow up in joy and face life with a smile. They never get tired. This reminds me of Stream in the Woods: "When the last drop of water has not run out, when the spring has not dried up, the water always keeps saying,' Sooner or later, we will flow into the ocean'.

In the current, I seem to see the sunrise, sunset and rest, time passes, nothing can stop their way.

In the current, I seem to see metabolism, which is a combination of ingenious creativity and mysterious laws of nature!

I would like to blend into the running water and run to the ocean as happily as they do!

4. The second volume of the fourth grade is about the scientific composition of water droplets.

Hello everyone! I am a small water drop. I live in Tianshan Mountain, grew up with Xuelian, played carefree with snow, and had a good time every day. But my dream is to go to the seaside. Finally one day, my dream came true. After I was illuminated by the sun, I flowed to the stream with my friends. In my imagination, the stream should be crystal clear and covered with pebbles. However, I was completely shocked by what I saw-the stream was muddy and gave off an abnormal smell. Some old ladies are flushing the trash can with a stream!

I was thinking: how did this happen? I need to get out of here. I fell into the river again. This river should be crystal clear in my imagination. There are many small fish, shrimps and crabs in it. I can play with them. However, in front of me, it is: the river is turbid, full of dead fish, dead shrimp and dead crabs. Some boys are dumping garbage into the river! I was thinking: Why? Why! Why! Why! I flowed into the lake again, and the lake should be crystal clear in my imagination. There are many small animals and plants in it, and I can play with them. However, what is presented to me is that the lake is very turbid and the small animals and plants in it have disappeared. Several people spit in the lake again, threw garbage, and even threw the bodies of several dead people into the lake, making the lake even more smelly. I thought: Why do humans pollute lakes like this? I finally flowed into the sea, the cleanest and most beautiful water in my dream, and the place I dreamed of. The sea is so clear in my imagination. There are many aquatic animals and various plants in it. I can ask them to tell me many stories about the ocean. However, today's sea has been scarred and can no longer withstand human destruction. However, some people still discharge the sewage and harmful water from factories into the sea. Looking at the damage of the sea and the pollution of streams, rivers and lakes, I am thinking: Why? Humans want us aquarium people to get hurt? Why destroy us and pollute us? Why do you want to kill us all and put us to death? Do you know that if we all disappear, you will commit suicide? In fact, the real culprit is yourself-human beings. I hereby appeal: "To protect and care for water resources, we should start from bit by bit, start from me, and fight for the guardian of water resources. Don't make us full of trauma, but also make Grandpa Earth a better place." Actually, everyone knows that. Why does our mother, the cradle, always overflow, causing human displacement? It is precisely because of human wanton destruction. When the sun rises again, I turn into steam, heaven, clouds, rain, arrival, and return to my hometown, Tianshan Mountain, where I was born and raised. Now that I have seen the snow and Saussurea involucrata in Tianshan Mountain, I know my home is the best!

5. Little knowledge of science in grade four (I)

Simple and easy-to-learn scientific knowledge

The mystery of automatic rotation

Thinking: Why do cartons full of water rotate?

Materials: empty milk box, nails, 60 cm long rope, sink, water.

Operation:

1. Punch five holes in the empty milk box with nails.

2. One hole is in the middle of the top of the carton, and the other four holes are in the lower left corner of the four sides of the carton.

3. Tie a rope about 60 cm long on the top hole.

4, put the carton on the plate, open the carton mouth, quickly fill the carton with water.

5. Lift the rope at the top of the carton by hand, and the carton rotates clockwise.

Description: the water flow produces equal and opposite forces, and all four corners of the carton are pushed by this force. As this force acts on the lower left corner of each side, the carton rotates clockwise.

Create:

1. If a hole is punched in the center of each side, how will the carton rotate?

2. If the hole is located in the lower right corner of each side, which direction will the carton rotate?

Boat and paddle

Thinking: Have you ever seen boating? Rowing by yourself? Do you know why the ship is moving on the water?

Materials: scissors 1, cardboard 1, rubber band 1, washbasin and water 1 basin.

Process:

1. Cut the cardboard into about 12cm * 8cm long.

2. One end of the bow is cut into a sharp shape, and the other end is cut out of the center of the stern by about 5 cm.

3. Cut a piece of cardboard about 3cm * 5cm to make ship pulp.

4. Tie a rubber band at the stern and tie an oar.

5. Turn the cardboard paddle counterclockwise and tighten the rubber band, and the boat will move forward.

6. If you turn the cardboard paddle clockwise to tighten the rubber band, the boat will move backwards.

Description:

1, the rubber band twists in different directions, but the ship's direction is just the opposite.

2. The power of paper boat movement comes from the energy of rubber band torsion.

6. What word is used to describe the landscape of Guilin in grade four?

World A means ranking first or surpassing others.

The best in the world is the best in the world. Lijiang River, also known as Gui Jiang, is about 50 kilometers long. It is located in the northeast of Guangxi Zhuang Autonomous Region and flows through Guilin.

Huge waves, huge waves. Magnificent, majestic and broad.

This lesson refers to the rolling waves and spectacular scenery of the sea. It also means grandeur or scale.

Jade minerals, generally green, some blue-green, or white with green stripes, have glass luster and can be used as decorations. Immaculate refers to the spots on jade.

Immaculate, that is, without spots, jade is very pure. In this paper, the water of Lijiang River is described as pure and clear.

Continuous connection, continuous. More refers to mountains, rivers, rain and snow.

The dangerous peak stands upright and refers to the height. Upright, refers to protruding high.

The dangerous peak stands tall, which means that the mountain stands upright. The rugged rocks describe towering and overlapping rocks.

Grotesque rocks refer to many grotesque rocks. The rippling water waves move together.

Watch and enjoy it. Something that protects like a screen.

(especially peaks, islands, etc. ).) Bamboo rafts are made of bamboo and tied in rows for ships to use.

Roll up to open the picture you are watching. Mount Tai is Dongyue.

In the middle of Shandong Province, the main peak is in the north of Tai 'an County, which is magnificent. Xiangshan is a scenic spot in the western suburbs of Beijing, with beautiful scenery, especially famous for its charming red leaves in autumn.

Level is like a mirror. When there is no wind, the water is as calm as a mirror. Get up from the ground and pull up hard.

Rising from the ground, used to describe a mountain peak or a large building that seems to rise from the ground. Clouds and mists make people unable to see the true colors of the mountains.

Magnificent, high and sharp peaks one after another, majestic and magnificent.

7. Writing landscape poems in the fourth grade is urgent.

Painting Dong Qichang, Ming Lan: lush green leaves, planted by stones, solitary roots not open.

Under the window of the mountain, the wine column spreads and the paper smells. Zhu Wei leans on the bamboo alone, and I play the piano and hum a song.

It's too light for anyone to hear, except my partner, Mingyue. Look at the snow peaks of Zhongnanshan, and Tang Zuyong looks at how Zhongnanshan is towering into the sky.

After the snow in Chu Qing, the afterglow of the sun shone from the forest. It was late, and Chang 'an was even more chilly. Chrysanthemum Tang Yuanzhen's autumn bushes are like Taoist priests, and the more they are surrounded, the more inclined they are.

It's not that chrysanthemums are favored among flowers, but that this flower is even more flowerless. Painting bluegrass in Zheng Banqiao, Lan Qing has taken place, which is a meaningful mountainous area.

Loyalty is still self-embracing, so why fight with others? Zhong Fang, the younger sister of Mountain Garden, shook off her unique beauty and let the amorous feelings go to the small garden.

"Mottled shadows hang obliquely on the clear shallow water, and their fragrance spreads peacefully in the moonlight dusk." Cold birds want to fly, first glimpse plum blossoms; Butterflies will be enchanting if they know the beauty of plum blossoms.

Fortunately, there are micro-songs to compare with, without a sandalwood * * * Jin Zun Du Fu's "Looking at Yue". What a magnificent sight of Mount Tai! ? Out of Qilu, green peaks can still be seen. The magical nature brings together thousands of beautiful mountains in the south and the separation between morning and dusk in the north.

Caiyun lave? My mind is free and easy, birds are flying around in front of my nervous eyes ... trying to climb to the top of the mountain: it dwarfs all the peaks under our feet.

Climbing Yueyang Tower, I've heard about Dongting Lake for a long time, and now I finally climb this building. The vast lake tore Wu Chu apart, as if the sun, moon and stars were floating in the water.

There is no news from my friends or relatives. I am old and sick, drifting in a boat. The battle of the north gate began again, and I cried through the railing.

"Looking for Flowers Alone by the Riverside" Huang Siniang's family is full of flowers, and thousands of them are low. The butterflies in the flowers are dancing, and the soft yinger in freedom is just singing happily.

Two orioles sing green willows, and a row of egrets go up to the sky. My window framed the snow-covered western hills. My door often says "goodbye" to ships sailing eastward.

If there is a spring boat on the cliff lake, I will carry it forward no matter what happens in the future And my boat and I, before the evening breeze, skimmed the flowers and entered the lake.

At dusk, I turned to the valley to the west, where I could see the southern star on the other side of the mountain. The mist rose and circled softly, and the low moon slanted through the Woods.

I choose to put aside all worldly things and just be an old man with a fishing rod ... Qingxi is from Wang Wei, and I have braved the wind and waves to cross the Huanghua River, and the thoroughfare is from Qingxi.

Ten thousand laps around the mountain in less than thirty miles. The rapids buzzed on the piled rocks, but the light dimmed among the dense pine trees.

The surface of an entrance swayed with nut horns, and weeds grew along the river bank. In my heart, I have always been as pure as this clear water.

Oh, stay on a wide flat rock and cast the fishing line forever! . Mount Zhongnan, with its huge height close to the city of heaven, connects Qian Shan to the corner of the sea.

The white clouds merged behind, and the blue mist melted into the mountains and disappeared. The central mountain peaks separate the southwest, and the valleys are different.

Want to find a house to live in the mountains, is it convenient for the water guide to ask the woodcutter? Meng Haoran's "Qiu Deng Wan Shan Send Zhang Wu", on a north peak among the white clouds, you found your hiding place.

Now, when I climb this mountain to see you, my heart flies high with the geese. Sadness is often the mood of dusk, and the mood is often the atmosphere of autumn.

I looked down at the riverbank and took a flat-headed rest with the folks who came home. The forest in the distance is like a shepherd's purse, overlooking the river bank like a crescent moon.

I hope you will pick me up, bring a basket of wine and get drunk on the Double Ninth Festival. A letter from Dongting Lake to Premier Zhang. On the eighth day of the first month, the lake here is an air with heaven.

Ozawa's water vapor transpiration on the cloud soil is white, and the waves seem to shake the whole Yueyang. I'm going to cross the water to find a boat and paddle. It's a shame to return home in the sacred age.

Sitting around watching other people's hard river fishing can only envy the fish caught in the fish. "From a berth on Tonglu to a friend in Yangzhou", I ran with the river all night.

The wind on both sides of the strait rustled the branches and leaves, and the moonlight reflected on the river, a boat on a river. Jiande's scenery is good, but it's not my hometown. I still miss my old friends in Yangzhou.

Recalling those two lines of tears that I couldn't restrain, I looked at the west side of the west bank and sent sadness to Yangzhou. On a clear morning, in a Buddhist retreat behind the Broken Mountain Temple, near the ancient temple, the early sunshine shone on the treetops.

A secluded place with bamboo paths, branches and flowers, to a Buddhist retreat. Here, birds live in the mountain light, and people's hearts feel quiet in the pond.

A thousand voices were quiet, but the bell rang. In Wang Zhihuan's "In the Heron Villa", the mountains cover the day and the sea drains the golden river.

By going up one flight of stairs sees Liangzhou Ci thousands of miles away. The Yellow River is far from the white clouds, and it is an isolated city, Wan Ren Mountain.

Why use the elegy of willow to complain about the delay of spring, old Yumenguan, a spring breeze is not blowing! Poetry, Wang, Linjiangzhu and Mingluan continued to sing and dance.

The painted building faces Nanpu Cloud, and the bead curtain rolls up the rain in the western hills at dusk. The shadow of the idle cloud pool is long, and things change for a few years.

Where is the emperor in the cabinet today? Outside the threshold, the Yangtze River flows by itself.

8. Four hundred words are urgently needed for aquatic reading notes for the fourth grade of primary school.

After reading Destiny, I feel that I bought a book in the book city a while ago, called "Dropping Water Hides the Sea", which contains 300 classic philosophical stories.

Now I'm going to taste a little story called fate. "Destiny" is about the fate of two children, one is divined by a monk as the "number one scholar" and the other is a beggar.

Twenty years later, the original champion became a beggar, but the beggar became a champion. God said, "the talent I give to everyone accounts for one-third of his fate, and the rest depends on how he grasps it."

After reading this passage, I was very moved. Grasp, grasp the fate, what a simple sentence, but how many people really grasp their own destiny? Don't blame your own talent, let alone your own fate, because fate is in your own hands and can be changed at any time! As long as you are willing to read A Farewell to Arms, you will feel that a person who bid farewell to weapons is either a prisoner of the enemy or a prisoner of love.

It's not that I'm not good at protecting myself. I am really a person who gives up self-protection. Just like the database of life, you can open all programs and read all files at any time without a password.

When I say prisoners, I mean prisoners in this sense. When I put myself in the sun, I understand that I can't pretend anymore, and I feel uneasy at the thought of hidden days.

When I realized the helplessness of resistance, how much time could not be recovered, and how many memories gradually faded out of my mind. In the final analysis, a prisoner is an irresistible person, that is, he must have enough courage to give up hope and must bear all the pressure of survival.

Originally in personal space, you can immerse yourself in the fantasy of solitude, and you can open virtual flowers from the dust. And a person who gives up self-protection can't even deceive himself, only constantly purify his inner world.

9. Unit 2 Oral communication in the first volume of Grade Four Chinese

Five Observation Diaries-Selected Works of Unit 2

It was sunny on September 26th.

Today, I did a very interesting experiment. Mom took out a lot of beans, wow! So many beans! This is mung bean, this is soybean, this is red bean and so on. There are so many kinds of beans. I chose several kinds of beans that grow easily. They are red beans, mung beans and soybeans. I put a little water in a small plate and then put the beans in the water.

It was cloudy on September 27th.

When I came home at noon, I looked at the beans in the water and felt very puzzled. What happened? Mung beans sprouted, but the skins of soybeans and red beans were wrinkled, just like a girl turned into an old woman. Why? At lunch, I asked, "Dad, why are the skins of soybeans and red beans wrinkled, while mung beans have sprouted?" Dad said, "Red beans and soybeans are bigger, so they need more water." So, I put more water on the plate.

It was cloudy on September 28th.

When I come home from school, I look at the dishes, yo! A bad smell is stuck in my nose. I just know when I ask, you can't put too much water in soaking beans. After this lesson, only a little water was added this time. However, soybeans and red beans have taken off inappropriate clothes and sprouted about 3 mm

It was sunny on September 29th.

I can't wait to see the beans in the water after I finish my homework, yo! Mung beans have leaves, but they are still closed, the buds turn green, and even the meat turns green. The buds of soybeans and red beans are already as long as the thumb. Moreover, I found a mystery when I observed it. Beans germinate before peeling.

It was cloudy on September 30th.

After lunch, the mung beans in the water have spread green leaves and some roots have grown at the bottom of the bud. So are red beans and soybeans. I am surprised that their growth rate is so fast. Through the observation these days, I learned something I didn't know before, and realized a truth-I can't do anything blindly.

This article comes from: Fang Liangjie