1. Car cab outside the rearview mirror is a convex mirror
Use of convex mirrors on the dispersion of light and into the orthogonal, reduced, virtual image of the characteristics of the physical object to see a small, greater range of observation, and to ensure the safety of driving.
2. The reflector in the headlights is a concave mirror
It is the use of concave mirrors can be placed on the focus of the light source issued by the light reflected into a parallel light out of the nature of the made.
3. Automobile headlamps are always fitted with a glass shade with horizontal and vertical stripes
An automobile headlamp consists of a bulb, a reflector and a glass shade in front of the lamp. According to the knowledge of lenses and prisms, automotive headlamp glass cover is equivalent to a combination of lenses and prisms. When driving at night, the driver should not only see the situation of the road ahead, but also to see the roadside holders, road signs, road junctions and so on. Lens and prisms have a refractive effect on the light, so the lampshade through the refraction, according to the actual need for light dispersed to the direction of the need to make the light uniformly and softly illuminated the road ahead of the car and the roadside scenery, at the same time, this light dispersal lampshade can also make a portion of the light upward refraction in order to illuminate the signposts and milestones, so as to ensure safe driving.
4. The car is equipped with a teal glass, pedestrians are difficult to see the face of the car
The teal glass can reflect part of the light, but also absorb a part of the light, so that the light into the car is weak. To see the passenger's face, it is necessary to reflect from the face of the strong enough light transmitted to the outside of the glass. Due to the weak light inside the car, there is not enough light transmission, so it is difficult to see the passenger's face.
5. In addition to large buses, the vast majority of cars are tilted front window
When the front window of the car tilted glass, the car passengers reflected by the glass into the country's front above, and the road pedestrians are unlikely to appear in the air above, so that the passengers in the car and the road pedestrians like the separation of the drivers will not be illusion. Large passenger cars are larger, the front window from the ground is much higher than the small car, even if the front window is mounted vertically, like the same height as the window, and the road pedestrians are unlikely to appear at this height, so the driver will not be the passengers in the window like the road pedestrians confused.
And then the following example:
Five-spice tea eggs are people love to eat, especially when eaten while hot flavor is more beautiful. Careful people will find that the eggs just out of the boiling marinade, if you are eager to peel the shell to eat the eggs, it is inevitable that even the shell with the "meat" together peeled off. To solve this problem, there is a trick, that is, just out of the pot of eggs in cool water first, then peeled, the shell will be easy to peel down.
Substances in general (with a few exceptions) are characterized by thermal expansion and contraction. However, different substances expand and contract at different rates and magnitudes when they are heated or cooled. Generally speaking, the density of the material, than the density of the material is easy to stretch, the expansion of the magnitude is also large, the heat transfer of the material, than the slow heat transfer of the material is easy to stretch. Eggs are made up of hard shells and soft whites and yolks, and they stretch differently. In the case of a small change in temperature, or a relatively slow and uniform change, it does not show anything; once the temperature changes drastically, the shell and the egg white expansion and contraction of the pace is not consistent. Boiled eggs immediately immersed in cold water, the shell temperature is lowered, and quickly contracted, while the egg white is still the original temperature, has not contracted, then a small portion of the egg white by the shell pressed to the empty head of the egg. Subsequently, the egg white is gradually shrinking because of the lowering of the temperature, and the contraction of the egg shell has been very slow, so that the egg white and the egg shell are separated, so that the peeling up will not even the shell with the "meat" down together.
Understanding this is very useful to us. Where the need to withstand large temperature changes in things, if they are made of two different materials together, then in the choice of materials, it is necessary to take into account the nature of their thermal expansion, the closer the two the better. Engineers have made extensive use of reinforced concrete in the design of houses and bridges, simply because steel and concrete expand almost exactly the same, and there are no harmful forces despite the different temperatures of spring, summer, fall, and winter, so reinforced concrete buildings are very strong.
In addition, some electrical components are made of two kinds of thermal expansion properties of the metal is very different. For example, the thermal expansion of copper than iron, copper and iron nailed together bimetallic sheet, in the same case of heat, it will be due to the expansion of different degrees and bending. The use of this property made many automatic control devices and instruments. Fluorescent lamps "starter" in the small bimetal, it changes with the temperature, can automatically flex, play the role of automatically turning on the fluorescent lamps.
These examples are numerous, physics is a very practical science, and industrial and agricultural production, daily life has a very close connection. The laws of physics are themselves a summary and abstraction of natural phenomena.
When it comes to physics, some students find it difficult; when it comes to physical investigation, some students find it unfathomable; when it comes to physicists, some students even feel that they are not mortal. It is true that there are only a handful of physicists, but as long as you are diligent in observation, good at thinking, the courage to practice, dare to innovate, from life to physics, you will find: in fact, physics is around. As Marx said: "Science is the science of experimentation, science lies in the rational method to organize the perceptual material". Physics is not only one of our subjects, more importantly, it is also a science.
Physics exists around physicists. Diligent observation of the Italian physicist Galileo, worship in Pisa Cathedral, hanging in the church in mid-air copper chandelier swing caused him great interest, and then repeated observation, repeated research, the invention of the pendulum isochronous; courageous practice of the United States physicist Franklin, in order to recognize the nature of the "God's wrath," in a Thunder and lightning, stormy days, at the risk of his life, the use of commonplace kites will be "God's fire" to invite down to earth, thus inventing the lightning rod; innovative British scientists Henry 6.1 Achard to go to the post office to do business. At that time, beside a foreigner took out a large version of the new stamps, ready to cut down a sticker on the envelope, suffering from no knife. He asked Achal to borrow it, but Achal didn't have one either. The outsider had an idea, removed the pin on the suit and tie, and neatly pierced a circle of small holes around the stamp, and then, very neatly, tore off the stamp. The outsiders went away, but left a string of deep thinking to Achard, and thus invented the stamp perforation machine, there are toothed stamps were born; the ancient Greek Archimedes found Archimedes principle; German physicist R?ntgen discovered X-rays; ...... study the trivialities around them and have a big achievement of the physicists of the examples are innumerable.
Physics also exists around the students. Learning the preliminary knowledge of measurement, the students have made a soft ruler. A student ingenuity, with transparent glue to make the kraft paper soft ruler wrapped, so more solid. Then, with a large roll of bubble gum box as a soft ruler shell, in the center of the box using wire to make a crank center shaft, the end of the soft ruler is fixed on the shaft, so that a tape measure can be packed and repeatedly used was born. At the same time, the students were inspired by the soft tape measure self-made, with experiments to solve an exercise: measure the length of the object with a soft tape measure, if the soft tape measure is stretched a little bit, the measurement value is big or small? He did such a simulation experiment: draw a straight line on white paper, marked with a scale, and then paste it with transparent glue, and then pull it down, it is made into a "soft ruler", with a "soft ruler" not only to find the answer to the question, but also clearly see that the graduated value has become larger, and the soft ruler can be used to measure the length of an object, if the soft ruler is stretched a little, the measured value is bigger or smaller? Know what it is, and know why; learn the knowledge of electricity, students of earthworms can withstand the maximum voltage to explore: when it added 1.5V voltage, earthworms quickly secrete mucus, and struggle, from the bottle jumped out of the bottle. When it is added to the 3V voltage, the earthworm was electrified into two; a student in the measurement of "2.4V, 0.5A" of the power of the small bulb, and to study its light-emitting situation, not satisfied with the bulb with a voltage of 2.4V, but with their own long-prepared small bulbs to do destructive experiments, and constantly increase the voltage on both sides of the bulb, until the voltage is as high as 9V, the bulb light bulb, the voltage of the bulb light bulb, the voltage of the bulb light bulb, the voltage of the bulb light bulb. Until the voltage up to 9V, bulb filament burned, only to stop exploring; some students in the study of evaporation of knowledge, tirelessly seated at the table to observe the same two drops of water (one of which a drop of water beach open), to concentrate on observation, and then analyze, compare and contrast, and arrive at the factors affecting the evaporation of; ...... students to capture the minutiae around them to carry on the examples of inquiry are commonplace.
The things around us are inexhaustible, and the physical subjects that are very closely linked to real life are even more often used to explain and summarize the laws of physics with examples around us, and the students sound familiar, and it is easy to accept them. As long as we pay attention to, and often summarize, we will continue to find things conducive to the teaching of physics, enrich our classroom, active teaching atmosphere, simplify the concepts and laws. The new standard tells us that "the physics curriculum of compulsory education should be close to students' lives, conform to the cognitive characteristics of students, stimulate and maintain students' interest in learning, and cultivate students' lifelong enjoyment of exploration, good habits of thinking and initial scientific and practical ability by exploring physical phenomena, revealing hidden physical laws and applying them to production and life practice. "
Today, all of mankind's amazing scientific and technological achievements, such as sheep cloning, the Internet, nuclear power plants, aviation technology, etc., are all built on the basis of early scientists who observed and studied the trivial things around them. In learning, students should establish a sense of science, the big picture, small start, experience observation, thinking, practice, innovation and other activities, and gradually master the scientific method of learning, training scientific way of thinking, soon you will have a scientist's mind, for their own future marveled at the development of the future of a better life to lay a solid foundation.