2. firewood yinhua firewood refers to fireworks, commonly known as fireworks. It consists of an upper part and a lower part. The lower part is equipped with propellant similar to gunpowder, and the upper part is equipped with combustion agent, combustion improver, luminous agent and color developer. Inorganic compounds containing various metal elements in chromogenic agent show various colors when burning, which is called flame reaction in chemistry.
3. Rock breaking Only the explosion of gunpowder can produce the effect of rock breaking. Gunpowder is one of the four great inventions in ancient China. The basic components of gunpowder are saltpeter (potassium nitrate), sulfur and charcoal. After they are mixed and heated in a certain proportion, a fierce chemical reaction occurs, producing a lot of light and heat.
4. Incompatible combustion is an oxidation reaction. Generally speaking, water can be used to put out fires. Because water is a nonflammable liquid, it can isolate air, absorb heat and reduce temperature. This is the truth that water and fire are incompatible.
5. Asking for fire with firewood (adding oil to the fire, making a drop in the bucket, and taking a salary at the bottom of the pot) is all about the relationship between combustibles and burning phenomena: holding firewood to put out the fire is definitely counterproductive; Adding fuel to the fire can only make the fire more prosperous; How insignificant it is to extinguish the flame produced by a cart of firewood with a glass of water; Moving firewood is still the way to cure the problem!
6. The process of hammering red-hot pig iron repeatedly in the air to turn it into hard steel is actually the process of continuously removing impurities and purifying pig iron.
Second, the material nature involved in idioms
7. Gold panning in sand is a rare metal, and its content in the earth's crust is only about 5%. It precipitates with sand to form a deposit, usually containing about 3- 10g of gold per ton of sand. At a very early age, people used the method of "panning for gold in sand", that is, gravity beneficiation. By using the density difference between gold and sand and washing it repeatedly, little gold was obtained from sand.
8. The elixir of life originated in the pre-Qin period. At that time, people carefully fired elixir of life with various mineral raw materials to satisfy the noble's desire for immortality. The ancient elixir elixir is some minerals, which mainly produce some inorganic compounds such as mercury oxide and mercury chloride after chemical reaction at high temperature. External use has some curative effects on sores and dermatitis, and it is not "smart" at all.
Third, the knowledge of life and diet in idioms.
9. Xiaoyi Wen is 6~ 10% acetic acid aqueous solution, so acetic acid is also called acetic acid. Vinegar is a common condiment in cooking, which can enrich the color, aroma and taste of food, stimulate gastric acid secretion, help digestion, wake up the stomach and prevent diseases. So jealousy is not good, but moderate amount is good for your health.
10, as sweet as sugar is maltose, which is an early sugar compound. It can be fermented with air-dried malt or grain. The main energy of human life-sustaining activities comes from the heat energy generated by the oxidation of sugar compounds, and sugar is also an indispensable condiment in daily life. Because of its unique sweetness, it is not surprising that it is as sweet as sugar.
1 1, protein and fat in milk are insoluble in water, but casein can be dispersed in water to form emulsion. The decontamination principle of detergent and shampoo is similar: water-insoluble oil is emulsified and dispersed in water-removed by mixing water and milk.