General knowledge of primary school science

1. All knowledge points of primary school science

Science 1 Unit 1 In the game, an object has a downward force, which is gravity.

2. For cars powered by rubber bands, the more times the rubber bands are wound, the faster they travel and the farther they travel. The fewer times the rubber band is wound, the slower the driving speed and the closer the driving distance. 3. When rubber bands, springs and other objects are subjected to external force, their shapes are easy to change. When their shape changes, they will generate a force to restore their original shape. This force is called elasticity.

4. Elastic bands of clothes and trousers, wallets, bows and arrows, tensioners and various springs all use the elasticity of objects. When the gas in the balloon is ejected, it will produce a thrust opposite to the ejection direction. This force is called recoil.

Jet planes and rockets are moved by recoil generated by jet engines. 6. To make delicate objects move, we must exert force on them; To make an object move faster, you must exert more force on it.

7. In science and technology, the Newton-based unit, referred to as "cow" for short, is uniformly stipulated and represented by "n". 1 Newton is approximately equal to 100 gram force.

8. Attention should be paid when using the spring dynamometer to measure gravity: (1) Pick up the dynamometer and check whether the pointer is in the "0" position first; (2) When reading, the line of sight is flush with the pointer; (3) The measured force shall not exceed the maximum value marked on the dynamometer scale. 9. When an object moves on the surface of another object, the contact surface of the two objects will be rubbed, and the moving object will be subjected to a force that hinders the movement. This force is called friction.

10, we use a dynamometer to pull an object in the horizontal direction, and the force that just makes the object move is the friction it receives. 1 1, the contact surface between objects is smooth and the friction is small; Roughness of the contact surface between objects will increase friction.

The heavier the object, the greater the friction when moving; The lighter the object, the less friction. 12. An object moves on the surface of another object in two ways: sliding and rolling.

Sliding friction is much larger than rolling friction. 13. When an object moves on the surface of another object, there will always be friction.

14, where the bicycle needs to be rubbed: there are patterns on the front and rear tires, pedal surfaces, brake rubber and handlebars; Where no friction is needed: front axle, middle axle, rear axle, pedal axle, large and small gears and chains. 15. Design features of the racing car: (1) The tires are very wide, which can increase friction and avoid slipping; (2) Design a powerful engine; (3) The center of gravity of the car body is very low, and the wheel spacing is wide, which can make the driving smooth; (4) Design a streamlined body to minimize resistance.

16. Both push and pull will generate force, and both push and pull will make the object move. Thrust and tension also have magnitude and direction.

When we push or pull an object on the ground, we feel laborious because there is friction between the object and the ground. 17. The balance is made according to the balance principle of the lever ruler.

Balance is an instrument to measure the quality of goods. When weighing the goods, put the weighed goods on the left plate and the weights on the right plate. If the weights are properly placed, the balance will be balanced left and right. If it is not balanced, adjust the travel code to make it balanced.

18. The weights of the balance are: 1g, 2g, 2g, 5g, 10g, 20g, 50g, 100g * * 9. When carrying heavy objects, do not hold them directly with your hands, but with your hands. At the end of weighing, the tray should stop swinging as soon as possible.

19. The compass is made according to the characteristic that magnets can indicate north and south. Compass is one of the four great inventions in ancient China.

One end of the magnet tube is called the South Pole, which is denoted by S, while the north end is called the North Pole, which is denoted by N ... the sun and time. Objects that can emit light by themselves, such as electric lights, are called light sources.

2. Like this, the shadows of objects illuminated from different sides are called projections. 3. Shadow must be composed of light source, screen and shelter.

4. The length of the shadow is related to the position and angle of the light source. 5. The size of the shadow is related to the distance from the light source to the object.

6. The shape of the shadow is related to the side of the illuminated object. 7. People in ancient times used sundials to record time.

Xiao Ming found that the shadow of the big tree faces west and the sun is in the east. 9. Light travels in a straight line at the speed of 300,000 kilometers per second.

10. When the light hits the mirror, it will change its propagation direction and be reflected back. This phenomenon is called light reflection, and light travels in a straight line. 1 1. There are forehead mirrors and reflectors that use light reflection.

12. The surface temperature of the sun is more than 6000 degrees Celsius, and the internal temperature is more than 20 million degrees Celsius. 13. Black rough objects have the strongest heat absorption capacity.

14. The vertical temperature rise of objects and sunlight is fast. 15. People use solar energy: solar cookers, solar panels, lighting the Olympic flame and solar water heaters.

16. There are concave mirror and convex lens for focusing light. 17. Pupils dilate under weak light and contract under light intensity.

18 We can use regular or rhythmic activities to estimate time, such as (counting heartbeat) and (tapping the table rhythmically). But according to our estimation, we can't know the time accurately.

19, time is passing at a constant speed. Usually, we think that the speed of time is how we feel at work. 20. Before the invention of the clock, people measured the time according to the position of the sun in the sky, making it at sunrise and resting at sunset.

2 1. In ancient times, we divided a day (day and night) into twelve hours, and each hour is now two hours. In ancient Egypt, a day was divided into (24) hours, (12) days and (12) nights according to the intersection of 36 constellations in the sky in a year. 22, (sundial) is to use the change of the position of the sun in the sky, so that the shadow length and position of objects on the ground change with time.

23. In a device, water can continuously flow downwards at a steady speed. According to this feature, humans made (water clocks) to time. 24. There are two kinds of ancient water clocks: water-receiving type and water-discharging type, both of which are made according to the change of water quantity.

25. In the dripping experiment, if the water flows downwards, the flow rate of the water is (not fixed), and with the decrease of the water volume, the speed becomes (slow). The less water in the container, the slower the water flows.

26. The time required for each swing of the same simple pendulum is (the same); According to the isochronism of a simple pendulum, people made pendulum clocks to reduce the measurement error of time. 27, placed in the middle.

2. Students' scientific knowledge

1. Why do the stars twinkle?

We see the stars shining, not because the luminosity of the stars has changed, but because of the occlusion of the atmosphere.

The atmosphere is between us and the stars. When starlight passes through the atmosphere, it will be affected by the density and thickness of the atmosphere. The atmosphere is not absolutely transparent, and its transparency will change according to its density. So when we look at the stars through it on the ground, we will see that the stars seem to be flashing.

2. Why do people yawn?

When we feel tired, a lot of carbon dioxide has been produced in our bodies. When there is too much carbon dioxide, oxygen must be supplemented to balance the needs of the body. Because these residual carbon dioxide will affect our body's functional activities, then the body will send out a protective reaction, so we yawn.

Yawning is a deep breathing action, which will let us breathe in more oxygen and expel more carbon dioxide than usual, and it can also eliminate fatigue.

3. Primary school science knowledge:

The trunk of a dog is supported by its forelimbs and hind limbs, which makes it higher from the ground and is conducive to running and jumping.

There are heart and lung organs in the back and chest, digestive organs and partial excretory reproductive organs in the waist and abdomen. The pelvis below the recommended position (including buttocks, pelvis, tail, etc.). ), including the digestive organs and the posterior segment of excreting reproductive organs. There are usually 4-5 pairs under the chest and abdomen.

The first pair is in the chest, and the other 3-4 pairs are arranged at a certain distance in the abdomen. The dog's abdomen is very compact and contracts upward, commonly known as the upper abdomen, which is conducive to running, jumping and chasing.

There are two little white pigs in my family. They are all white, and their big ears are like two powerful fans, flapping up and down; Long nose, a pair of round nostrils, like two small caves; There is a big mouth hidden under the nose. If you don't look carefully, you won't find a mouth under your nose. There are a pair of unpredictable little eyes on the nose, and the wrinkles on the face are really not pretty. The newborn kitten closed its eyes, made a thin cry, and was naked, like a crawling meat ball.

After the full moon, all the villi grow together. Some collars are white, the limbs are covered with white hair, the back is black and gray, and the tail is gray and black; Some people wear a dark coat from beginning to end, but the soles of their feet are white. People say it is an excellent variety, called "black clouds cover snow"; Some are yellow and tiger-patterned, and people have given it a good name "gold does not change"; There is also a kind of white hair and black hair tail, which is called "dragging a gun in the snow"

A full-moon cat can't walk without milk. The crab is half the size of my palm. Except for the abdomen, its shell is turquoise, as if wearing a green gown. Its hard body is like wearing a suit of armor.

Look, those thick crab claws seem to pose as "fists". Ah, those eight steps, each of which consists of seven bars, are like eight slender "seven-section sticks".

One section of the tip is claw-shaped, and the other sections are flat strips or short columns. There are some fine hairs on the steps, which add a little momentum to this magnificent appearance. It's a coincidence that the students are swinging in the air with flower handkerchiefs. The peacock really opens its screen.

I saw a peacock wagging its tail loudly. That beautiful tail is like a colorful fan in the fairy's hand, spreading slowly, and like a bright pearl sprinkled on it, which is very beautiful. When the tail is open, it is bright and dazzling.

Those peach-shaped patterns, the outer ring is gray, the second ring is light blue, and the last ring is sapphire blue with a little dark red, which is really beautiful. It can be proud, hold its head high, hold its chest out, turn back and forth and show off its beauty.

4. Students' scientific knowledge

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Why do pupils see lightning first and then hear thunder? (Light travels faster than sound in air) Who was the first Olympic champion in China? (Xu Haifeng) 3 Who invented glasses? (Luigi, Bacon) 4 Why does the bicycle move? (Bicycle tires rubbing the ground) 5 Whose title is below? (Poet Xian-Li Bai, poet Sheng-Du Fu, Shi Gui-Li He, landscape poet-Meng Haoran, pastoral poet-Tao Yuanming) What does June Ming revolve around? How long is a cycle? (Earth) (24 hours) 7 What are the three major plains in China? (Northeast Plain, North China Plain, Middle and Lower Reaches of the Yangtze River) 8 How many earthquakes occur on the earth every year? (About 5 million times) 9 What is the smallest and coldest star? (Pluto) 10 What is the thickness of the earth? (Atmosphere) 1 1 Why is there a black box on the plane? It is used to record all kinds of situations on the plane during the crash and help people understand the cause of the accident. 12 What are the customs during the Spring Festival? (Sweep the house, set off explosions, post Spring Festival couplets, eat New Year's Eve, etc. ) 13 what animals can predict earthquakes? Cows, horses, donkeys, rabbits, chickens, dogs, snakes, rats, cats, swallows, eagles, etc. ) 14 what plants bloom first and then shed leaves? (Forsythia suspensa, Winter jasmine, Chimonanthus praecox, Peach Tree and Pear Tree) 15 How do bees make hives? Every worker bee has a wax gland at the waist, which can secrete wax. This wax becomes soft and tough after chewing in the mouth, and can be used to build a honeycomb. Why is the 16 medicine bottle so light? Because light color can reflect light, dark color absorbs more light when exposed to sunlight, and drugs are easy to deteriorate) 17 Who invented the steam engine? (Watt) 18 Which dinosaur is the hardest? (Stegosaurus) 19 What is the blood of the earth? (Magma) 20 What is the skeleton of the earth? (Rock) 2 1 Why don't you watch the welding sparks? Why can't I turn it off?

5. Science teaching stories in primary schools

The results of teaching practice and reflection must be disseminated. Some plants are self-pollinated, while others are cross-pollinated. If pollination is not good, the results will be bad, just like sunflowers. This spring, two sunflowers were born in my family, one in the east and the other in the west, about eight meters apart. We water and fertilize it, and it grows day by day. The one in the west is very strong, with a sunflower diameter of 65438+. Sunflower seeds are getting more and more full, and our family is very happy except my mother. I think: my mother can't read, and she has seen a lot in the countryside, so she naturally feels normal. During the autumn harvest, I specially invited six students from the nature interest group, as well as my daughter and niece, to have a harvest festival together. When I picked the heavy sunflower, these greedy cats blossomed around. I picked one and it's empty. Everyone can't wait to eat. The third, fourth and sum are still empty, and occasionally one or two are full. I am very disappointed, so I appeal to everyone to find a way to choose an empty one. A classmate brought a basin of water. We put sunflower seeds in the basin and floated them all. I was not convinced, so I divided the sunflower seeds into nine parts and let everyone pinch them with their hands and choose the full ones. After a few minutes, sunflower seeds were selected. A total of 1 175 sunflower seeds, only 87 are ripe, which surprised everyone. At that time, I looked at those empty seeds with full surfaces and wondered. Curiosity generated the motivation to learn, and everyone collected some knowledge and pictures about pollination. Through inquiry learning and cooperative exchange learning, they have a deep understanding of the importance of fruit formation and pollination.

6. Primary school science knowledge How to keep animals and plants warm when the cold winter comes?

Animals have ways to keep out the cold, and people will add clothes to keep out the cold. What about the animals in the zoo? It turns out that there is a clever way to keep out the cold. Let's go and have a look. People only hate wearing less clothes these two days, and some small animals in the zoo are also afraid of the cold. The rabbit's cage is covered with canvas to keep out the cold, and waterfowl don't go into the water. The kitten curled up on the haystack, the horse covered with a quilt, and even the tortoise hid under the haystack. Small animals that are afraid of the cold all got into the breeder. There are no signs of monkeys these two days. If you look carefully, they are all huddled in the lee of Monkey Mountain, hugging each other for warmth. Three strong lions still "live on it", but if the temperature continues to drop and it rains, they have to be boarded to prevent them from sleeping directly on the concrete floor and catching cold. Even this camel is the most comfortable in the cold wind. Compared with the temperature of tens of degrees below zero in the desert, this kind of weather is a piece of cake. The temperature has plummeted in these two days. They cover the cages of small animals with thick straw to shield them from the cold wind, enrich their recipes, increase energy-based foods such as wheat and enhance their ability to resist cold weather. In winter, plants that help plants keep out the cold are alive, but in the face of severe cold, some plants often turn yellow and die because they can't adapt. What are the simple, economical and quick ways to prevent cold? To this end, the reporter invited Lin from Wantong Garden Company to teach you a trick. Method 1: "Dress" to prevent cold. "Dresses" were originally wrapped in linen, but never in plastic bags. Plants are alive and need sunshine and air. Hemp is the best "clothing material", especially for newly planted plants, which have few roots and weak vitality. At the same time, they need careful care. Covering the whole factory. The black net is about one or two yuan/meter. But many families don't like black, so they can choose green net. However, the price will be twice as expensive. These products will be sold in Guangzhou Lingnan flower and other wholesale markets. Method 2: Reduce the "burden" Many people think that it is enough to "add clothes" to plants in winter. As we all know, plants should reduce their burden. Lin said that the more leaves there are, the greater the area of plants that are frozen. Prune plants properly before the cold current comes, but pruning is learned. The tools used should not be too sloppy, and the stationery scissors should not be used casually. It is suggested to use "big flower scissors", which are sold in Fangcunyue and the world of flowers, birds, fish and insects, ranging from 20- 100 yuan. Good scissors are durable and not easily deformed. It is best to choose products with hard blades, thick blades and strong handles. Method 3: Move in time. In winter, the north wind is particularly strong, and the tuyere position should avoid plants. If possible, move some potted plants indoors, away from windows. But don't let plants spend the whole winter indoors. It is suggested that they be basked in the sun when the weather is fine. Method 4: Simple heat preservation. The storage box with inner frame used by ordinary families can be used as a greenhouse for plants. Put a proper amount of small potted plants, add water not exceeding the height of the inner frame, and cover it to make a simple incubator. Because there is steam circulation in the "secret room", there is no need to water the plants alone at ordinary times. Tips for heat preservation: Which plants are more afraid of cold? Plants from tropical areas are more afraid of cold, such as pueraria lobata, indigo leaf, meconopsis prostrate, arrowroot, rich tree, black nightshade, old sunflower, Zhu Jin and so on.

7. All the scientific knowledge of grades 3 to 6 in the primary school science curriculum.

Science review materials for primary schools 1, the human body * * * has 206 bones and * * * has more than 600 muscles, and the weight of muscles accounts for 40% of the body weight.

2. Bones have the functions of movement, support and protection. Movable joints between bones are called joints, and all kinds of actions of human body are realized by the contraction and relaxation of muscles to drive bones and joints.

3. The advantages of regular exercise are: improving the flexibility of the body; Enhance myocardial and vital capacity; Muscular; Full of physical strength; Delaying aging; Body symmetry. 4. The main nutrients that people need are: protein, carbohydrate, fat, vitamins and minerals.

The kinds of food we eat every day are: grain, vegetables and fruits, fish eggs, soybean milk, oil, salt and sugar. Eating the most is food.

You should eat the least oil, salt and sugar. 6. The main digestive organs of human body are mouth, esophagus, stomach, small intestine, large intestine and * * *.

In order to eat safely, vegetables and fruits should be fully soaked and washed, eat more green food and eat less pickled food. 8. Pay attention to the production date and shelf life when buying processed food.

9. No food contains all the nutrients the human body needs, so we should eat food in a diversified and comprehensive way. 10, fruits cannot replace vegetables.

Air 1, air is mainly composed of nitrogen, oxygen, a small amount of carbon dioxide, water vapor and other gases. If harmful substances are added to the air, the air will be polluted and the airflow will form wind. The ancients in China invented the Kongming Lantern according to the rising principle of hot air.

2. Combustion must meet three conditions at the same time: combustible, oxygen and a certain temperature. Air is also the source of life, but human activities are the main cause of air pollution.

Some measures to prevent air pollution include planting trees, saving energy, driving less cars, improving car fuel, prohibiting burning straw and using fluorine-free refrigerators. You can touch it with your hands or put it in a plastic bag to feel the air. Air is a colorless, odorless and tasteless transparent gas.

5. Screw the funnel with rubber stopper on the bottle mouth and pour the water into the funnel. Can water flow into the bottle? Why? Water can't flow into the bottle, because the space in the bottle is occupied by air, and the rubber plug seals the mouth of the bottle. If the air can't get out, the water in the funnel can't get in. 6. Use ice cubes to cool food. Should the food be put on the ice or under it? Why? Food should be placed under the ice, because the air around the ice will sink quickly when it is cold, and the sinking air will surround the object to be cooled, so as to achieve the purpose of cooling as soon as possible. )

7. Air is compressible, and compressed air is elastic. Why can't bicycle tires be inflated too much in hot summer? Air has the property of expanding when heated and contracting when cooled. Due to the high temperature in summer, the air in the tire is exposed to high temperature, and the volume will inevitably increase rapidly, resulting in great pressure. When the tire can't bear such a big pressure, it will burst. Astronomy 1, the position of the sun in the sky can be expressed by direction and height. The phenomenon that the sun rises and falls day and night is actually formed by the rotation of the earth from west to east.

It's just that we live on the earth and take the earth as a reference, so it seems that the sun is in the east, the shadow is in the west, the sun is in the south, the shadow is in the north, the sun is in the west, and the shadow is in the east. Sun clock is formed according to the changing law of the shadow direction of objects under the sun. Sun clock in the Palace Museum is called the sundial, which belongs to the equatorial sundial. The sundial preserved by Nanjing Purple Mountain Observatory is called horizon sundial. The image of the bright part of the moon is called the moon phase.

The new moon refers to the invisible moon in the sky. The moth-eyebrow moon at the beginning of the month means that the sun has just set on the horizon, and the moon phase we see is facing the sun.

The moth-eyebrow moon at the end of the month means that when the sun is about to rise, the moon phase you see is also facing the sun. 5. Looking at the moon from the first day to the fifteenth day at sunset, I found that the moth-eyebrow moon is in the west, the first quarter moon is in the south, the convex moon is in the Middle East, and the full moon is in the east.

It can be seen that the direction of the moon's revolution around the earth is from west to east. 6. Looking at the moon from 16th to the end of the month at sunrise, I found that the moon on 16th is in the west, the last quarter moon is in the southern sky, the waning moon is in the middle east, and the moth moon is in the east.

7. In a day, the moon rises in the east and sets in the west. This is because the earth rotates from west to east.

The moon is the satellite of the earth, and it is a month in the lunar calendar for the moon to go around the earth. Motion and force 1. When we ride a bicycle, the wheels are moving in a straight line and rotating.

2. The speed of the truck is related to factors such as self-weight, tension and road surface. The unit of force is Newton.

4, when using dynamometer, to make the pointer at 0, can't exceed the maximum measuring range. When an object is subjected to an external force, its shape or volume will change, and it can be restored to its original shape or volume after removing the external force. This property is called elasticity, and this force is called elasticity.

6. Everything on the earth has a vertical downward gravity. This force is due to the gravity of the earth.

7. Judgment: Force can change the motion state of an object. (Right) The elasticity of an object is infinite. When an object passes through liquid or air, it will also produce friction. (right) 8. Friction generates heat, and the formation of meteors is related to friction. In hot summer, the car tires on the expressway will be hot; There are many examples of increasing beneficial friction (such as patterns on tires and handlebars) and reducing harmful friction (adding lubricating oil and ball bearings to mechanical moving parts).

9. The shape of an object is related to the friction it receives. For example, the descending speed of a parachute is related to the size of its canopy. Water 1, water is the source of life, and water is a colorless, odorless and tasteless transparent liquid.

Water has three states: solid, liquid and gas. Clouds, fog, rain, dew and frost are all condensed by water in the air.

2. The common ways to know objects are to look, smell with the nose, taste with the tongue and touch with the hands. Don't smell or taste what you don't know. What is the way to identify water, salt water, sugar water, milk and white vinegar in a cup? Water has the force to make its surface as small as possible, which is called the surface tension of water.

4. Iron will sink in the water, but why can steel boats float on the water? Because the steel ship has a large space and is lighter than the same volume of water, it floats on the water. Most of the water on the earth is salt water in the ocean, only a little.