Man made glass more than 5000 years ago. Archaeological evidence shows that in Egypt and Mesopotamia in 3000 BC, people have made some small handicrafts such as amulets and beads with glass.

　　By around 1500 BC, people’s skills in making glass were becoming more and more mature, and the first glass container appeared in human history. The ancient Egyptians also mastered the technology of coloring glass. They know that adding copper powder to glass can make red glass, adding cobalt powder can make blue glass, and adding tin powder can make white glass … These colored glasses are used by some unscrupulous businessmen to pretend to be jewelry, deceiving many people.

　　In the 1st century BC, Syrians invented the technology of blowing glass. With this technology, making glass becomes simple, fast and cheap. Since then, the glass industry has flourished in the Roman Empire and quickly spread to other countries under the rule of the Roman Empire.

　　Around the 1st century A.D., the Romans discovered that adding a proper amount of manganese dioxide to glass could make colorless glass, so they began to make windows out of glass and install them on buildings. Although the optical performance of glass at that time was very poor, glass windows were still "standard" for buildings in Rome, Pompeii and other places.

　　In the 8th century, Venice concentrated a large number of glass workers and became the glass manufacturing center at that time. Later, with the progress of science and art, people "played" more tricks, such as dyeing paint on glass and drawing colorful patterns. Many churches we see now have stained glass windows, which is the architectural style left over at that time.

　　In the mid-15th century, a glass worker in Venice invented a new type of super transparent glass. Soon, this new type of glass was used to make telescopes, thermometers, flasks, microscopes and other scientific instruments, which led to many important scientific discoveries.

　　Around the 18th century, the glass manufacturing center in Europe moved from Venice to Britain. At that time, the output of British glass factories was very high. At one time, the British government would levy taxes based on the number of windows in each house, on the grounds that wealthy families would install more windows, and of course they should pay more taxes. However, "there are policies above and countermeasures below", and many families simply blocked the windows in order to avoid paying taxes-this story shows that the use of glass was quite common in Britain at that time.

　　Since the industrial revolution, steel and glass have become important building materials for modern architecture. In 1851, Britain built a "Crystal Palace", which only used steel and glass. This miraculous building was also the exhibition hall of the first World Expo in London. In 1950s, a German architect innovatively covered the facade of the building with a layer of glass, which made the appearance of the building look unprecedented. This innovative design can be successful, on the one hand, because there is a reinforced frame inside the modern building, and the facade does not need to bear the weight of the whole building; On the other hand, because the strength of glass has become higher. So many skyscrapers we see now have glass facades.

　　Nowadays, scientists and engineers have developed a variety of glasses, which have important uses in many fields. For example, there is a kind of glass that can quickly transmit network information, that is, optical cable, which is filled with thousands of glasses as thin as hair, in which communication signals shuttle in the form of light and quickly transmit information to all parts of the world.

　　Sand and glass

　　The main component of glass is silica, that is, Shi Ying, which is one of the most common minerals on the earth. The sand that can be seen everywhere is actually a small particle in Shi Ying. When Shi Ying is heated to 1400℃, it will melt, then become soft and become a transparent, viscous liquid-then it will be cooled and shaped, and then the glass will be finished.

　　How did sand become glass?

　　On the atomic scale, silicon dioxide is composed of silicon atoms and oxygen atoms, and they are arranged in order in Shi Ying. For example, a group of silicon atoms and oxygen atoms are neatly arranged to form a "queue" with specific arrangement rules, and the whole "queue" is Shi Ying particles. A structure like this, which consists of a large number of microscopic substance units (such as atoms and ions) arranged in an orderly manner according to certain rules, is called a crystal.

　　After Shi Ying melted, its internal crystal structure was destroyed, or the original "queue" was disrupted, and silicon atoms and oxygen atoms began to "run" freely, making Shi Ying change from solid to liquid. Of course, if the liquid Shi Ying can be cooled quickly, the crystal structure will be re-formed, just like the silicon atoms and oxygen atoms that "run" at will "stand" in the original position in the queue again.

　　However, if the cooling speed is too fast, so that silicon atoms and oxygen atoms can’t return to their original positions, then they can only be condensed in their current positions. Therefore, the final glass is like a snapshot of liquid Shi Ying. Scientists have a special name for this state of solid, called "amorphous solid", which means that this kind of solid is different from crystal, and there is no orderly arrangement rule in its internal structure.

　　Why is glass transparent?

　　We can’t go straight through the glass, but our eyes can see the objects on the other side through the glass. Why?

　　We can see an object because the light is reflected or scattered after it reaches this object, which makes some light enter our eyes and let us see the shape and color of the object. Only a part of light energy is received by our eyes, and the rest is absorbed or intercepted by objects.

　　How much light an object can intercept depends on the kind of molecules or atoms that make it up.

　　Most of the atoms in the glass don’t intercept light, and almost all the light that reaches the glass can be received by the eyes (glass can intercept ultraviolet light, but our eyes can’t see ultraviolet light). In addition, glass is not crystal, and there is no edge edge edge of crystal structure inside, so it will not scatter light. So, when the light reaches the glass, it will go straight through without changing its direction.

　　However, if a piece of glass is slightly thicker in some places, the propagation path of light will be bent, which is the working principle of a prism.

This article is from Science Illustrated.

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The length, width and height of BMW i4 are 4785mm, 1852mm and 1455mm respectively, and the wheelbase reaches 2856mm. The side lines of the car body are smooth and matched with 18-inch rims, in which the front wheel tyre size is 245/45 R18 and the rear wheel tyre size is 255/45 R18, which further enhances the sense of movement and handling performance of the car.

The interior style of BMW i4 is full of modern technology and luxury atmosphere. The center console is equipped with a 14.9-inch high-definition touch screen, which integrates multimedia system, navigation, telephone and air-conditioning voice recognition control system, making it easy to operate. The steering wheel is made of leather, which feels comfortable and supports manual adjustment up, down and forward to meet the needs of different drivers. There are multiple USB and Type-C interfaces in the car, two in the front row and two in the back row. At the same time, the front row is also equipped with wireless mobile phone charging function, which provides convenience for passengers. In terms of seats, both the driver’s and driver’s seats support multi-directional adjustment, including front and rear, backrest, height, leg rest and lumbar support, and the front seats have heating function. The seat material of BMW i4 is rich, and you can choose imitation leather, genuine leather or fabric/suede materials to meet the individual needs of different consumers. In addition, the driver’s seat also has an electric seat memory function, which improves the driving experience. The rear seats support proportional tilting, which further enhances the practicability of the vehicle.

BMW i4 is equipped with a high-performance motor with a maximum power of 250 kW and a maximum torque of 430 Nm, which provides excellent power performance for drivers.

According to the owner’s evaluation, the design of BMW i4 is really impressive. He said: "The configuration parameters of Series I’s 3, 5 and X3 are almost the same, except that the shell has been changed. I want to buy I4 for more than 100,000 yuan. Of course, it is still imported, and there is no need to do such a thing as buying it home. At first glance, the big nostrils are not mediocre. When I drive out, people are guessing at 600,000. I am sorry. " This design and personalized configuration make the BMW i4 a unique model, which not only satisfies the owner’s pursuit of face value, but also brings full pride.

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BMW i4 adopts a unique front face design, and its kidney-shaped air intake grille is endowed with new life, which combines the futuristic feeling of electric vehicles with BMW’s traditional aesthetics. The enclosed design of the grille not only shows its status as an electric vehicle, but also effectively reduces the air resistance and improves the energy efficiency of the vehicle. The body lines are smooth, and the waistline on the side of the body extends from the front fender to the rear of the car, creating a dynamic visual effect. The rear part is mainly based on concise design language, and the slender LED taillight group echoes the light group at the front, and at the same time enhances the overall recognition of the vehicle. The exterior design of BMW i4 not only embodies the cutting-edge technology of electric vehicles, but also retains the consistent sports style and luxury temperament of BMW brand.

The side lines of BMW i4 are smooth and dynamic, with a body size of 4785 * 1852 * 1455mm and a wheelbase of 2856mm. The front tread is 1601 mm and the rear tread is 1630 mm, which ensures the stability and handling of the vehicle at high speed. In addition, it is equipped with 18-inch wheels with 245/45 R18 front tires and 255/45 R18 rear tires, which further enhances the vehicle’s grip and driving experience.

The interior design of BMW i4 shows the perfect combination of luxury and technology. The center console is equipped with a 14.9-inch super-large touch screen, which is easy to operate and has excellent display effect. Drivers can use the voice recognition control system to easily control the multimedia system, navigation, telephone and air conditioning, which greatly improves the convenience and comfort of driving. The steering wheel is made of high-quality leather, which provides a good grip and supports manual adjustment up and down and back and forth to meet the needs of different drivers. In addition, the front row is also equipped with a mobile phone wireless charging function, which is convenient for drivers to charge their mobile phones at any time. In terms of seats, BMW i4 offers a variety of choices, including imitation leather, genuine leather and leather /Alcantara mixed materials. The main and auxiliary seats all support a number of electric adjustments, including front and rear adjustment, backrest adjustment, height adjustment, leg rest adjustment and lumbar support, ensuring the comfort of long-term driving. The front seats also have a heating function, which further enhances the driving experience. The rear seats support proportional reclining, providing more storage space.

The engine of BMW i4 has a maximum power of 210 kW and a maximum torque of 400 Nm, which provides strong power performance for the vehicle.

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