Silicon dioxide (SiO2) has an irreplaceable position in the history of human development.

As a substance with excellent physical and chemical properties, silicon dioxide is rich in nature and harmless to human beings. Since it was developed, it has been welcomed by everyone.

Jewelry industry, sculpture industry, construction industry, glass manufacturing industry, timing tool manufacturing industry … these industries can develop to today's extent without the help of SiO2. This paper mainly discusses the influence of silicon dioxide on the development of timing tools.

The development of timing tools can be seen from distant ancient times. At first, the chronograph tower used in ancient Egypt, the invention of sundial and water clock, the widespread use of hourglass, the appearance of mechanical clock in14th century, the era of pocket watch and pendulum clock … and then the quartz clock which has been widely used until now appeared in the 20th century. After that, there appeared an atomic clock that was more accurate than the quartz clock ... However, the quartz clock is mainly discussed here.

The working principle of quartz clock is to count the number of times a clock chip vibrates continuously in the clock. As for the more specific working principle, please refer to the paper devoted to this principle.

The chip can vibrate because it is piezoelectric. Piezoelectricity is simply: give it a little pressure and it will release voltage. or vice versa, Dallas to the auditorium

In quartz clock watches, the main feature is that "when it is electrified, it will generate force". Electrify it and it will vibrate. If the frequency of electricity given to it is fast, it can vibrate rapidly and continuously. As it happens, many things that generate electricity can easily provide an alternating electric field to make them vibrate quickly.

Because its vibration requires little electric energy, its vibration energy consumption is small, its vibration frequency is stable, and its physical and chemical properties are excellent and stable, many timing tools are based on its vibration to time. Moreover, because of its stable nature, the vibration frequency is little affected by the chip size, so it is also suitable for manufacturing small watches.

There are two main reasons why seasonal watches are so popular in today's society: accuracy and cheapness.

Compared with the previous hourglass and mechanical clock, the timely timing is more accurate (because its vibration frequency is stable). Compared with the new atomic clock, quartz clock is cheaper (because it is "ubiquitous" in nature, and the development price is low). Therefore, using it to make watches is the most suitable in the current environment.

You can investigate if you don't believe me. Is there a watch on your wrist, a timer in your computer, a clock in your mobile phone ... that doesn't contain SiO2?

Look at the essence from the phenomenon.

From the widespread use of silicon dioxide, we can see its influence on the timekeeping industry.

(2) Chemistry and War

First, the combination of noble and ordinary-graphite bomb

Graphite bombs are made of specially treated carbon wires (this knowledge is in the carbon element of senior one chemistry in People's Education Edition). The diameter of each carbon wire is quite small, only a few thousandths of a centimeter, so it can float in the air for a long time. Because the carbon wire is made by fluid energy grinding and chemical cleaning, the conductivity of the carbon wire is greatly improved. Carbon filaments are not sticky, but they can be attached to all surfaces. Scattered in enemy positions by explosion or gunpowder detonation, destroying enemy air defense and power generation equipment. Carbon wires can enter electronic equipment, cooling pipes and black boxes of control systems. Carbon wire warheads are destructive to everything, including airplanes parked on runways, electronic equipment, power grids of power plants and so on. In the early 1990s, during the Gulf War, graphite bombs made their debut in the "Desert Storm" operation. At that time, the US Navy launched a ship-borne Tomahawk cruise missile, threw graphite bombs at Iraq and attacked its power supply facilities, paralyzing 85% of the power supply system in Iraq. At the end of 1990s, in the air raid on Yugoslavia by NATO led by the United States, the graphite bomb used by the United States Air Force was BLU- 1 14/B, and the Fll7A stealth fighter first attacked the southern power grid on1May 2, 1999, resulting in power failure in 70% of southern China.

Second, the true portrayal of crossing the sea-smoke bombs

As we all know, "smoke" in chemistry is composed of solid particles and "fog" is composed of small droplets. The principle of smoke bomb is to cause a wide range of chemical smoke in the air through chemical reaction. For example, after a smoke bomb filled with white phosphorus is detonated, white phosphorus burns rapidly in the air. The reaction equation is: (This knowledge is in "Nitrogen Group Elements" in Senior Two Chemistry of People's Education Press) P2O5 will further react with water vapor in the air to generate metaphosphoric acid and phosphoric acid. The toxic reaction equation of metaphosphoric acid is: P2O5+H2O=2HPO3, 2P2O5+6H2O = 4hpo4, and these acid drops react with unreacted white particles.

Similarly, silicon tetrachloride, tin tetrachloride and other substances are also easy to hydrolyze.

SiCl4+4H2O=H4SiO4+4HCl, SnCl4+4H2O=Sn(OH)4+4HCl, that is, they combine in air to form HCl acid mist, so they can also be used as smoke bombs. During the First World War, the British Navy used aircraft to drop smoke bombs containing SnCl4 and sicl4 on its warships, thus cleverly hiding the warships and avoiding the enemy's bombing. Smoke bombs used in some modern new military tanks can not only hide the physical appearance, but also have the function of avoiding infrared laser and microwave, thus realizing real "stealth". Telling this knowledge in teaching will stimulate students' infinite imagination and enhance their learning motivation.

Third, open the combination of the light of heaven and the fire of hell-incendiary bomb.

Have you seen Saving Private Ryan? An American soldier burned the enemy soldiers in the tunnel with incendiary bombs, which is one of the functions of incendiary bombs in modern tunnel warfare and trench warfare. Because of its low density, high calorific value and low price, gasoline is widely used as the raw material of incendiary bombs (this knowledge is in Chapter 2 and Chapter 5 of Senior High School Chemistry of People's Education Press). Napalm is made by adding an adhesive that can combine with gasoline to form a gel. In order to attack targets in water, some still add active alkali metals and alkali metals, such as potassium, calcium, barium, etc., and the hydrogen released by the combination of metal and water will be re-combusted, which improves the burning power (this knowledge is in the second chapter of chemical alkali metals in senior high school of People's Education Press).

For armored tanks, incendiary bombs have their own ingenious ways to deal with them. Because aluminum powder and iron oxide can have spectacular aluminothermic reaction, 2Al+Fe2O3=Al2O3+Fe+ heat (this knowledge is in the fourth chapter of high school chemistry of People's Education Press), the heat released by this reaction is enough to melt steel into liquid state, so incendiary bombs made of aluminum agent can melt the thick armor of tanks, making them daunting. In addition, thermite incendiary bomb can still burn without air combustion, which greatly expands its application scope. Use this knowledge in teaching and cultivate their creativity.

Fourth, the product of human progress and killing-gunpowder.

Gunpowder was first invented and manufactured by working people in China, and was mainly used in medicine. According to Compendium of Materia Medica, gunpowder has the functions of eliminating moisture, eliminating plague and treating sores and mosses, which can be seen from the word "medicine" in gunpowder. Later, gunpowder spread to Europe before it was used in the military. The composition of military black powder is: 75% potassium nitrate, 10% sulfur, 15% charcoal (sometimes the powder is brown, also called brown powder). Black powder is extremely easy to burn violently, and the equation is:

(This knowledge is in the sixth chapter of the first year of high school chemistry in People's Education Press)

At the same time, the heat generated by combustion makes the gas expand violently and explode.

With the development of military chemistry, high explosives with greater explosive power than black powder appeared. Generally, it is an organic compound containing nitro groups. First, picric acid, which is explosive, is made of phenol. The reaction equation is:

(This knowledge is in Chapter 6 "Derivatives of Hydrocarbons" of Senior High School Chemistry Grade Two in People's Education Press)

Nitroglycerin is the main component of a high explosive accidentally discovered in a chemical laboratory. It is formed by nitration of glycerol (glycerol), and the reaction equation is:

(This knowledge is in the sixth chapter of the second year of high school chemistry in People's Education Press.)

Later, TNT appeared, which is now widely used as an explosive in military weapons and as a standard. It is formed by nitration of toluene, and the reaction equation is:

(This knowledge is in the fifth chapter of "Hydrocarbons" in the second year of high school chemistry in People's Education Press)

In addition, ammonium nitrate is a good nitrogen fertilizer and a high explosive. When it is suddenly heated to a high temperature or violently impacted, it will explode. The reaction equation is:

(This knowledge is in the first chapter of Chemistry in Grade Two, People's Education Press, "Nitrogen Family Elements")

There have been explosions of ammonium nitrate (used as fertilizer) warehouses at home and abroad.

As for smokeless gunpowder, it is made of cotton (the main component is cellulose) by nitration, and its chemical name is cellulose trinitrate, which is introduced in high school chemistry textbooks. If you talk about this knowledge in teaching, you will increase your interest in learning and expand your students' knowledge. Why not?

V. Technology and Death-Chemical Weapons

After the Gulf War, an important purpose of UN weapons inspection in Iraq is to eliminate its chemical weapons, which can be used deadly. The first application of chemical weapons in history was on April 22, 2005. The Germans used chlorine gas on a large scale in the battlefield in Belgium, which led to the poisoning of 5000 people, including 5000 deaths. Bitter hydrocyanic acid kills people without seeing blood. Endure it in World War II, which will seriously lead to death; Signal flares of various colors can be made by using flame reaction (this knowledge is in the second chapter of high school chemical alkali metals in People's Education Press); Ferrite chemical coating can absorb radar waves and can be used as the external coating of stealth aircraft. The knowledge of using AgZ or dry ice to carry out artificial catalytic rainfall operation is in the fourth chapter of high school chemistry of People's Education Press), which can form rainstorm and flood and become "meteorological weapons", as well as three nuclear weapons brothers-* *, hydrogen bomb and neutron bomb. These have their presence in high school chemistry theory.