Common sense of scientific homework in grade four 1. Little knowledge of science in grade four (Volume I)
Simple and easy-to-learn little knowledge of science
Mystery of automatic rotation
Thinking: Why does a carton full of water rotate?
materials: empty milk carton, nails, 6cm-long rope, sink and water
Operation:
1. Punch five holes in the empty milk carton 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 6cm long to the top hole. Fill the paper box with water quickly
5. Lift the rope at the top of the paper box by hand, and the paper box rotates clockwise
Explanation: The water flow produces equal and opposite forces, and all four corners of the paper box are pushed by this force. Because this force acts on the lower left corner of each side, the carton rotates clockwise
to create:
1. How will the carton rotate if the hole is punched in the center of each side
2. In which direction will the carton rotate if the hole is located in the lower right corner of each side
Boat and paddle
Thinking: Have you seen boating? Row the boat yourself? Do you know why the ship moves forward on the water?
materials: 1 pair of scissors, 1 piece of cardboard, 1 piece of rubber band, 1 basin of washbasin and water
process:
1. cut cardboard with a length of about 12 cm *8 cm
2. cut one end into a sharp shape to be the bow, and cut a gap of about 5 cm at the center of the other end to be the stern
3. cut a cardboard with a length of about 3 cm *5 cm. And tie the boat oar
5. Turn the cardboard paddle counterclockwise to tighten the rubber band, and the boat will move forward
6. If the cardboard paddle is turned clockwise to tighten the rubber band, the boat will move backward
Description:
1. The rubber band twists in different directions, and the boat will travel in the opposite direction.
2. The power of paper boat movement comes from the energy of rubber band twisting.
2. Science tips for Grade Four (Volume I)
Mystery of automatic rotation of simple and easy-to-learn science tips: Why does a paper box full of water rotate? Materials: empty milk carton, nails, 6 cm long rope, sink, water operation: 1. Punch five holes in the empty milk carton 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 6 cm long on the top hole; 4. Put the carton on the plate, open the carton mouth, and quickly fill the carton with water; 5.
Because this force acts on the lower left corner of each side, the carton rotates clockwise to create: 1. How will the carton rotate if the hole is punched in the center of each side? 2. In which direction will the carton rotate if the hole is located in the lower right corner of each side? Thinking: Have you seen boating? Row the boat yourself? Do you know why the ship moves forward on the water? Materials: 1 pair of scissors, 1 piece of cardboard, 1 rubber band, washbasin and 1 basin of water. Process: 1. Cut the cardboard with a length of about 12 cm *8 cm. 2. Cut one end into a sharp shape for the bow, and cut a gap of about 5 cm at the center of the other end for the stern. 3. Cut a cardboard boat paddle with a length of about 3 cm *5 cm. 4. Put the rubber band around the stern and tie the boat paddle properly. 5. Turn the rubber band counterclockwise. 2. The power of paper boat movement comes from the energy of rubber band torsion.
3. What are the scientific knowledge of the fourth grade
1. Weather unit
1. We can describe the weather through weather characteristics such as cloud cover, rainfall, temperature, wind direction and wind speed.
2. A table that records various weather phenomena every day is called a weather calendar.
3. the function of weather calendar: record and analyze meteorological information, summarize the previous meteorological laws and predict future weather changes.
4. In the weather calendar, the simplified wind speed grades are used to divide the wind speed: is no wind, 1 is a breeze, and 2 is a strong wind.
5. When using the thermometer, you can't read until the liquid column in the thermometer stops rising or falling.
6. Temperature has a great influence on the weather and is an important record data in the weather calendar. By observing and measuring the temperature of the atmosphere around us, we can know the local temperature. Temperature refers to the temperature in a cool and ventilated place outside. The outdoor temperature in a cool and ventilated place can better reflect the local temperature.
7. The law of temperature change in a day is that it rises first and then falls, with the lowest temperature in the morning and evening and the highest temperature at 2 o'clock in the afternoon.
8. Wind direction refers to the direction in which the wind blows. For example, the north wind blows from north to south. Wind direction can be measured by wind vane. The direction pointed by the wind vane arrow is the wind direction. If the arrow points south, it is the south wind. Eight directions can be used to describe the wind direction: east, south, west, north, southeast, northeast,
southwest and northwest.
9. The speed of wind is calculated by how many meters it travels per second. Anemometer is an instrument for measuring wind speed. Meteorologists shorthand the wind into 13 grades. Wind direction and wind speed are also important data in weather observation.
1. Precipitation is a basic feature of weather and an important data in weather calendar. Common forms of precipitation are: rain, snow, hail, fog, frost and so on. Rain gauge is a device to measure the amount of precipitation. The unit of precipitation is millimeters. Straight containers can be used as rain gauges. (Write down a precipitation scale on page 13 of a book)
11. Clouds floating in the sky are actually made up of thousands of small water droplets or ice crystals in Qian Qian, and their shapes are varied.
12. according to the amount of clouds, it can be divided into sunny days, cloudy days and cloudy days. I will use pictures to show the amount of clouds in various weather. In the book P14)
13. Meteorologists divide clouds into three categories: cumulus clouds, stratocumulus clouds and volume
4. Seek more scientific common sense questions, the better
Scientific common sense exercises, single choice questions 1. The purpose of protecting the environment is (). A. Reducing pollution B. Maintaining ecological balance C. Protecting animals and plants D. Beautifying human living environment 2. The "green revolution" is. It rose in (). A. 196s B. 197s C. 198s D. 197s Mid-197s 3. Anesthetics were first used in ancient China (). A. Bian Que B. Hua Tuo C. Zhang Zhongjing D. Sun Simiao 4. Which of the following were not Edison's inventions (). A. Law of electromagnetic induction B. Look at this matter from a scientific point of view, because (). A. People have joys and sorrows. B. The earth rotates around the sun and the moon rotates around the earth, and the two rotate at different speeds, resulting in a declination, which makes the earth cover part of the moon. C. The earth rotates around the moon at different declinations. D. The sunlight is uneven. 6. In the construction industry of western developed countries, plastic doors and windows are widely used instead of wooden doors and windows, *. The fundamental reason for this result is that () A. Metal doors and windows are expensive B. Plastic doors and windows have the lowest cost C. The builders who use plastic doors and windows can enjoy tax reduction and exemption D. The use of plastic doors and windows is beneficial to the protection of non-renewable resources 7. The Pythagorean theorem was first cited in the existing literature in China () A. Nine Chapters of Arithmetic B. Weekly Calculations C. Vertical and Horizontal Diagram D. ). A. The sunlight is too strong. B. The Antarctic is too cold. C. Because of the large amount of fluorine compounds emitted in human activities. D. There is too much carbon dioxide in the air. Another invention, which is as famous as atomic energy, semiconductors and computers in the 9th and 2th century, is (). A. Space shuttle B. Spacecraft C. Optical fiber D. Laser 1. Ocean technology has two marking technologies, namely (). A. Seawater desalination and offshore fishing B. Offshore oil production and desalination C. Deep-sea excavation and desalination D. Deep-sea excavation and mariculture 11. It is generally believed that high technology includes six major fields. The forerunner of these six high technologies is (). A. Communication technology B. Information technology C. Computer technology D. Biotechnology 12. The legendary "ghost fire" phenomenon is actually caused by the release of part of the reaction energy in the form of light energy during the oxidation process of an element in the human body. This element in the human body is (). A. Calcium B. Iron C. Phosphorus D. Potassium 13. (). A. Blue B. Green C. Yellow D. Red 14. The inventor of the first practical helicopter was (). A. Wright brothers B. Watt C. Sikorsky D. Faraday 15. In March 1994, The guiding document on the medium-and long-term plan for China's economic and social development adopted by the Standing Committee of the State Council is () A. China's Agenda for the 21st Century B. China's Agenda for the 21st Century C. China's Agenda for the Development and Planning in the New Century D. China's Agenda for the Development in the New Century The pillar of technology in the 21st century will be () A. New energy technology B. New material technology C. Space technology D. Information technology 17. And the cutting-edge technology of engineering, the currently recognized technical fields include (). A. Six major fields B. Eight major fields C. Four major fields D. Seven major fields 18. Environmental protection includes two aspects. They are pollution prevention and (). A. Protection of rare organisms B. Protection of nature C. Control of pollution D. Purification of air 19. The limit of the automatic adjustment ability of an ecosystem is called (). A. Ecological limit B. Ecological threshold C. Ecological national limit D. Extreme ecological value 2. The two landmark technologies of space technology are space shuttle and (). A. Satellite communication B. Measurement and control technology C. Permanent space station. Multiple-choice questions 1.b2.a3.b4.a5.b6.d7.b8.c9.d1.c11.b12.c13.d14.c15.a16.b17.a18.b19.c2.c.
5. 2 words in the fourth grade
Mystery of automatic rotation
Thinking: Why does the paper box full of water rotate?
materials: empty milk carton, nails, 6cm-long rope, sink and water
Operation:
1. Punch five holes in the empty milk carton 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 6cm long to the top hole. Fill the paper box with water quickly
5. Lift the rope at the top of the paper box by hand, and the paper box rotates clockwise
Explanation: The water flow produces equal and opposite forces, and all four corners of the paper box are pushed by this force. Because this force acts on the lower left corner of each side, the carton rotates clockwise
to create:
1. How will the carton rotate if the hole is punched in the center of each side
2. In which direction will the carton rotate if the hole is located in the lower right corner of each side
Boat and paddle
Thinking: Have you seen boating? Row the boat yourself? Do you know why the ship moves forward on the water?
materials: 1 pair of scissors, 1 piece of cardboard, 1 piece of rubber band, 1 basin of washbasin and water
process:
1. cut cardboard with a length of about 12 cm *8 cm
2. cut one end into a sharp shape to be the bow, and cut a gap of about 5 cm at the center of the other end to be the stern
3. cut a cardboard with a length of about 3 cm *5 cm. And tie the boat oar
5. Turn the cardboard paddle counterclockwise to tighten the rubber band, and the boat will move forward
6. If the cardboard paddle is turned clockwise to tighten the rubber band, the boat will move backward
Description:
1. The rubber band twists in different directions, and the boat will travel in the opposite direction.
2. The power of paper boat movement comes from the energy of rubber band twisting.
6. The scientific knowledge around you is quick, quick, quick, quick, quick
1. When taking medicine, don't use tea to deliver the medicine, because the tea party neutralizes the medicine and reduces its medicinal properties.
2。 It is harmful to drink tea when you have a fever, because theophylline contained in tea will increase the temperature of the human body and affect and reduce the effect of drugs, thus aggravating the illness. Therefore, it is not advisable to drink tea when you have a fever.
3。 Wearing red clothes can absorb and filter out more ultraviolet rays from the sun, thus reducing the damage of ultraviolet rays to the skin.
4。 Children should not eat sugar on an empty stomach, because it will affect their normal metabolic function
5. Putting fresh eggs in limewater can keep them fresh, because the carbon dioxide exhaled by eggs reacts with limewater to generate calcium carbonate, which blocks the micropores on the egg surface to prevent oxidation and deterioration.
6。 In order to prevent food from getting wet, deteriorating or deforming, gas carbon dioxide or nitrogen is often filled in food bags; Or put desiccant in the bag: quicklime and calcium chloride mainly absorb water, while iron mainly absorbs oxygen and water; Or vacuum package.
7。 The main gases in the swim bladder are carbon dioxide and oxygen
8. It is important to add some soda ash when making steamed bread. In order to neutralize the acid generated during flour fermentation, the generated carbon dioxide can make bread loose and porous.
9。 The residual pesticides in vegetables can be soaked with alkaline substances, which can reduce the medicinal properties of pesticides
1. The astringency of preserved eggs can be removed by adding vinegar
11. The odor of refrigerator can be removed by activated carbon, which makes use of the adsorption of activated carbon.
12。 The scale on the aluminum pot (the important components are calcium carbonate and magnesium hydroxide) can be removed with hydrochloric acid or vinegar
1. When the battery runs out of power and stops moving, its second hand often stops at the position of "9" on the dial. This is because the second hand is most hindered by the heavy torque at the "9" position.
2. Sometimes, when the tap water is discharged from the adjacent faucet, there are occasional bursts of noise. This is because the water pipe vibrates when the water rushes out of the faucet.
3. When taking pictures on the TV screen, you should turn off the camera flash and indoor lighting, so that the pictures you take are clearer. Because the reflected light of flashlights and floodlights on TV screens will interfere with the transmitted light of TV pictures.
4. Frozen meat thaws faster in water than in air at the same temperature. Burning nails in water is better than in air at the same temperature.