Physical knowledge in folk proverbs
In daily life, we often come into contact with some folk proverbs and aphorisms, which contain rich physical knowledge. If we pay attention to analyze and understand some folk proverbs and proverbs, we can deepen and activate our knowledge in real life, which is of great help to cultivate our ability to analyze and solve problems. Here are a few examples:
1, a little heavy-according to the principle of lever balance, if the power arm is a fraction of the resistance arm, then the power is several times the resistance. If the weight of the arm is very large, it is entirely possible to "dial one or two kilograms."
2. Broken mirrors cannot be reassembled-when the distance between molecules is large (more than several hundred angstroms), the attraction between molecules is very small, almost zero, so it is difficult to reassemble broken mirrors.
What you can't catch is the flowers in the water that the mirror can't catch-the flat mirror forms a virtual image.
4. Everyone is United, and Mount Tai is the top-if the components are in the same direction, the resultant force is equal to the sum of the components.
5, hemp rope to lift tofu-can't lift it-when the pressure is constant, if the stress area is small, the pressure will be great.
6. Real gold is not afraid of fire, and truth is not afraid of argument-from the melting point of gold, although it is not the highest, it also has 1068℃, while the temperature of general flame is about 800℃. Because the temperature of the flame is lower than the melting point of gold, gold cannot be melted.
7, the moon is dizzy and the wind is blowing, and the foundation is wet and rainy-when the wind comes, the air temperature drops rapidly and the water vapor condenses into small drops. These small water droplets are equivalent to many prisms, and the moonlight is dispersed through these "prisms" to form colorful halos, so it is called "moon halo wind".
The basic nourishment is the ground against the tide. Before the rainstorm, the air humidity is high, the ground temperature is low, and the water vapor near the ground condenses into small water droplets. In addition, the salt contained in the ground is easy to absorb wet water vapor, so the ground is against the tide, which indicates shanghai dawn.
8, a long whistle, the sound of mountains and valleys should be-people shouting in the mountains, the sound can form a loud echo after repeated reflection, lasting for a long time. As if the mountains were shouting and the valleys were echoing.
9, but smell the sound, don't smell people-in the process of wave propagation, when the size of the obstacle is less than the wavelength, obvious diffraction can occur. Generally, the height of the fence is several meters, and the wavelength of sound wave is larger than the height of the fence, so you can enclose the high wall for people outside the wall to hear; The wavelength of light wave is shorter (about 10-6 meters), which is much smaller than the size of a high wall, so the light emitted by people cannot be diffracted outside the wall, and people outside the wall can't see people inside the wall.
10, boiling water doesn't ring, ringing water doesn't open-before the water boils, bubbles in the water rise and vibrate up and down due to convection, and most of the bubbles burst under the pressure of water, and their cracking and vibrating sounds produce * * * sounds with the container, so the sound is very loud. After water boils, it is isothermal up and down, and the bubble volume increases. Under the action of buoyancy, it will burst as soon as it reaches the water surface, so the noise is relatively small.
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12, fire and water are incompatible-when a substance burns, it must reach the ignition point. Because of the large specific heat of water, water can absorb a lot of heat when it comes into contact with fire, which reduces the temperature of the ignited object; At the same time, the vaporized water vapor surrounds the burning object, making it impossible for the object to contact with air. Without air, combustion cannot be carried out.
13, a day in the cave, the world has passed for thousands of years-according to Einstein's theory of relativity, sailing in a spaceship near the speed of light, the passage of time will be much slower than on the earth. Living in this "cave" for a few days, the earth has spent several years, decades, even hundreds and thousands of years.
14, clairvoyance, clairvoyance-people use electromagnetic waves to transmit sound and image signals, making the ancient myth of "clairvoyance, clairvoyance" come true. And human vision has far exceeded "thousands of miles".
15, sitting on the floor, walking 80,000 miles a day-because the radius of the earth is 6,370 kilometers, every time the earth turns around, the distance that objects on its surface "walk" is about 40,003.6 kilometers, about 80,000 miles. This is a poem sung by Mao Zedong, which scientifically reveals the relationship between motion and stillness-motion is absolute, and stillness is always relative to the reference object.
16, bottom of the pot-there are two conditions for the liquid to boil: one is to reach the boiling point, and the other is to continue to absorb heat. If you take a salary, you can stop the liquid from boiling.
17, the flowers in the wall are fragrant outside the wall-because of irregular movements, the flowers in the wall will spread outside the wall.
18. It is rare to see the sky from the well-because light travels along a straight line, and from the knowledge of geometric drawing, it can be known that the frog's field of vision will be very small.
19, fidgeting-according to the pressure formula, when the pressure is constant, the smaller the stress area, the greater the pressure. People will feel very uncomfortable sitting on such a blanket.
20. Xue Rui shines brilliantly in a good year-there are many loose gaps in the fallen snow, which is filled with stagnant air and is a bad conductor of heat. When it is covered on crops, it can prevent heat conduction and air convection, so it can play a role in heat preservation.
2 1, cold before frost, cold after snow —— In the late autumn night, the temperature near the ground suddenly becomes cold (the temperature is below 0℃), and the water vapor in the air condenses into small ice crystals and adheres to the ground to form frost, so it feels "cold before frost". When snow melts, it needs to absorb heat to reduce the temperature of the air, so we have the feeling of "cold after snow".
22, a drop of water can see the sun, a thing can see the spirit-a drop of water is equivalent to a convex lens, according to the law of convex lens imaging, you can have the image of the sun through a drop of water, to see the big.
23. Eggs touch stones-overreaching-eggs touch stones, although the force is the same, but the pressure that each object can bear is certain. If this limit is exceeded, the object may be damaged. Eggs can withstand less pressure, so they will break.
24, paper can't wrap fire-paper will burn when it reaches the ignition point.
25. There is a natural fragrance of musk deer, so why should it rise in the wind-the diffusion of gas.
26. Jade must be cut before grinding-before grinding, the surface is uneven and the light is diffuse. After polishing, its surface is smooth and the light is specular.
27, the fan has a cool breeze, suitable for summer but not for winter-the use of fans in summer accelerates the flow of air and accelerates the evaporation of sweat on the human surface. Because evaporation absorbs heat, people feel cool.
28. Man struggles upwards and water flows downwards-it is an objective law of nature that water flows downwards, because water flows downwards from height under the action of gravity.
29. The water tank sweats without load-the water in the water tank has evaporated, and the temperature below the water surface is lower than the air. When the water vapor in the air meets the outer surface with low temperature, it will liquefy and the water droplets will adhere to the outside of the water tank. On sunny days, due to the low water vapor content in the air, although it will liquefy on the outer surface of the water tank, a small amount of liquefied matter will evaporate quickly and cannot form water droplets. However, if the air is humid, the water will evaporate slowly and outside the water tank.
30. Snow does not freeze snow-snow is formed by condensation of water vapor or water droplets in the sky. Coagulation and solidification are exothermic processes, and snow melting is a melting process, which requires heat absorption.
3 1, snow falls on the mountain, first frost plain-snowy day, the temperature on the mountain is lower than that on the flat ground below the mountain, and the snow falling on the mountain is not easy to melt, but the snow falling on the flat ground is easy to melt in time. So the same snow falls on the mountain, and the frost is the result of condensation of water vapor on the ground. There is more water vapor on the flat land below the mountain than on the mountain, so the flat land is easy to mix with frost, while the mountain is not easy to form.
32. Rome wasn't built in a day-the temperature of water is between 0℃ and 4℃, and the density of water is the highest at 4℃. When the overall water temperature drops to 4℃, the convection of water stops. The temperature continues to drop, the upper water temperature drops below 4℃, the density does not sink, the bottom water temperature keeps 4℃, and the upper water temperature drops to 0℃ to continue to emit heat.
33. There must be wind next to the fire-the air near the fire is heated and expanded, and the cold air in the distance will be poured in, and the flow of hot and cold air will form wind.
34. A stone breaks the water surface-the calm water surface is like a flat mirror, and you can see the image of the sky. When the stone is thrown into the water, it destroys the calm water surface, forming layers of water waves, and the image of the water is broken.
35. It is a waste of wax for the blind to light a lamp-the reason why people can see everything in the world is because sunlight or light used for lighting shines on an object, and the light reflected by the object enters the eyes of the blind, but the reflected light cannot enter the eyes of the blind, so the blind can't see the object.
36. It rains in the morning and at night-most rain clouds in China move from west to east. The rainbow seen in the morning is a western rainbow formed by sunlight from the east shining on water droplets in the rain layer in the western sky. Obviously, the rainbow in the west is a sign that the local weather is going to rain. On the contrary, the rainbow seen in the evening is an oriental rainbow formed by sunlight from the west shining on water droplets in the rain layer of the eastern sky, indicating that there are no rain clouds in the western sky and the weather is over.
37, the morning glow don't go out, sunset walk thousands of miles-(see above)
38. The rainbow is high and the sun is low. You wear hemp fiber in the morning and evening-when the sun is low, the sun is very close to the horizon. At this time, a rainbow appears. The center of the rainbow must be close to the horizon, and the half arc of the rainbow can be seen on the ground. If there are a lot of water droplets in the air at this time, and the distribution space is wide, then you can see not only the rainbow, but also the neon, and the half arc at the top of the neon is higher than the rainbow.
39. Photographic negative-Reversing black and white-The camera is made by applying the principle of placing the object out of the focal length of the convex lens twice, so the image on the photographic negative is reversed from the image of the person. The negative film is coated with a photosensitive agent. When people take pictures, the reflected light enters the black box of the camera and is photochemical with the photosensitive agent on the negative film, while the dark part has a strong ability to absorb light. Only a small amount of reflected light enters the negative. In this way, the light-colored part has strong sensitivity on the film, and the dark-colored part has weak sensitivity. When the film is developed, the photosensitive part is basically washed away, so it is light, and the photosensitive part is dark because it can't be washed away by photochemical reaction.
40. Sharpening the knife does not mistake the woodcutter-reducing the compressed area and increasing the pressure.
4 1, Eggs hit the stone-one step beyond the thunder pool-Eggs hit the stone, although the force is the same, but the pressure that each object can bear is certain. If this limit is exceeded, the object may be damaged. Eggs can withstand less pressure, so they will break.
42. You need a hand to clap your hands-force is the action of objects on objects. One hand can only clap the other hand, or clap on other objects to generate force.
43, four or two to dial a thousand pounds-the balance condition of the lever, increase the ratio of the arm of force to the arm of resistance, and use only a small force to pry up a heavy object.
44. Mercury falls to the ground-everywhere-the density of mercury is greater than that of the substances that make up the ground, and mercury is mobile, so it always sinks under other substances.
45. Make friends with loaches and eels-slide around-the surfaces of loaches and eels are smooth and lubricated with little friction.
46. When the egg hits the stone-it's over-the pressure on the eggshell is far less than the pressure that the stone can bear. When the egg hits the stone, it breaks first.
47. The ship is leaking-there is pressure in the liquid. After the ship is broken, put the water pressure outside the ship into the ship until the water surface inside and outside the ship is uniform, and then the water inside the ship will not flow out.
48. The gourd on the water can't sink-the density of the gourd is less than that of water, so it can only float on the water.
Learn physics from poetry and prose
Have you read these poems? They must have left a deep impression on you: ① "Until, I raised my cup, I asked the moon and drank three people"; (2) "Sit on the floor, travel 80,000 miles a day and look at thousands of rivers"; (3) "Flying down three thousands of feet, it is suspected that the Milky Way has set for nine days", "The Yellow River is far above the white clouds" and "The autumn wind whistling on the 8 th, on my San Mao"; (4) "Speak in a distant voice, not from the autumn wind"; ⑤ "The bright moon wears clouds like Bai Lianhua". Now we study these poems from the perspective of physics and find that they describe respectively: ① plane mirror imaging; (2) The earth keeps rotating and revolving (relativity of motion); (3) Lushan waterfall water, Yellow River water and flowing air contain a lot of mechanical energy; (4) the position of sound source and sound propagation distance; ⑤ Relativity of mechanical motion.
As can be seen from the above examples, many poems and sentences can be linked with physical knowledge and compiled into questions and answers, which can not only consolidate our physical knowledge, but also examine our humanistic quality and ability.
For example, it is recorded in China's ancient book Kao Ling Yao:' People are sitting on the boat, the windows are closed, and people are not watching when sailing. "Please explain why. Although ancient Chinese is quoted in the title, the meaning is simple, which vividly shows that there must be a suitable reference to describe the mechanical movement of objects. Answering such questions can not only appreciate the insights of the ancients when writing, but also impress people with their ability to master knowledge of nature.
Another example is "Thousand Characters", one of China's ancient enlightenment books, which said that "Yun Teng caused rain and dew to become frost". Do you agree with it that' dew turns into frost'? Why? "This problem not only requires a correct distinction between liquefaction, solidification and sublimation, but also inspires us to hold a correct view on the inheritance of ancient cultural heritage.
Cleverly integrating rationality into the text can also enhance the expressive force of the article and give readers unexpected composition skills lessons. In his novel "Social Drama", Mr. Lu Xun described a passage on the way to Zhaozhuang to see a play and sail: "The rolling mountains on both sides of the strait run all the way to the stern, like the iron ridges of animals." Isn't it used to set off the "relativity of movement" that "I" am eager to see the play? The article "Mountain Picker" describes that mountain pickers take the "Z" route when they go up the mountain, which just lays the foundation for us to learn the knowledge of "inclined plane".