General knowledge of natural sciences refers to the part of the civil service examinations that provides a comprehensive examination of expertise in the fields of physics, chemistry, biology, geography and astronomy. This section requires candidates to have a solid disciplinary base, to have a deep understanding of basic concepts, to have a core doctrine and to be able to apply the relevant theory flexibly to solve practical problems. The scope of the study covered the macro-cosm structure, microparticles movements, patterns of material transformation and ecological variability. This paper aims to systematize the high-frequency test points in this area, help candidates to establish a clear knowledge framework and improve the response logic and response efficiency。
The sun is the most spectacular star in the universe, with a surface temperature of 5,500 degrees celsius and a strong electromagnetic radiation. According to internationally accepted astrometric data, the mass of the sun accounts for 99. 8 per cent of the entire solar system, while its volume is as high as 99. 8 per cent, which is essentially the absolute core of the symmetrical structure of the solar system. At the gravitational level, the sun has a gravitational radius of approximately 150 million kilometres, which is sufficient to bind all materials in earth orbit. The orbit around the sun is elliptical, with a distance of 1,474,000 kilometres and an average distance of 150 million kilometres. The earth's rotation cycle is 365 days and the rotation cycle 24 hours. These astronomical commons form the basis for understanding the earth's environment and are a key starting point for solving the problem。
Water is liquid at constant temperature pressure and has unique physical properties. The ice point is 0°c, the boiling point is 103. 96°c and the temperature difference between the boiling point and the ice point is 113°c. This temperature margin is very significant in nature and is an important indicator of the water phase. The density of liquid water is about 1,000 kg per cubic metre, while the density of solid ice is slightly less than that of water, about 917 kg per cubic metre. When the ice melts into water, the volume decreases by about 9 per cent, which is the underlying cause of the ice floating on the surface. In meteorology, the evaporation potential of water is as high as 2,500,710 kj/kg, which explains why large amounts of thermal energy can be released in the event of severe water fluctuations. In addition, water has an extremely high corrosive capacity to absorb or release large amounts of heat and little temperature change, which plays a decisive role in regulating the earth's climate。
The law of continuity of energy is one of the cornerstones of physics, expressed in a way that neither energy can be created nor eliminated, but can be transformed from one form to another. Within the thermodynamic system, energy is manifested in internal energy, kinetic energy, power, etc. According to the international unit system definition, the energy unit is joule. In the course of chemical reactions, the energy within the atomic nucleus remains constant, and the chemical key is transferred or restructured. For example, chemical energy is converted to thermal energy in combustion reactions, while photocosynthesis is used to convert solar energy to chemical energy stored in organic matter. These principles are of direct application in the analysis of energy conversion efficiency and the calculation of reaction thermal parameters。
The movement of geological formations is an expression of energy releases within the earth. The tectonic theory suggests that the earth's surface consists of several rigid plates that move on the floppy circle. There are two main types of crustal movements at the plate boundary: collisions and crowding lead to mountain rises, such as the formation of the himalayas, and stretching causes rift valley or sea expansion, such as the great rift valley in east africa. Earthquakes and volcanic eruptions are violent phenomena caused by the movement of the earth's crust, with energy derived from thermal energy generated by the decay of radioactive elements within the earth. The production mechanism of the geomagnetic field involves a convection movement of liquid iron nickel from the outer nuclear, a process that has lasted for 44 billion years and is still being maintained。
The formation of meteorological phenomena depends on the state of the atmosphere and its interaction with the ground. The pressure values are significantly influenced by temperature, humidity and altitude. At high altitude, air density is reduced and the quality of gas in a unit of volume is reduced. Depending on the equation of the desired gas state, higher temperatures increase the pressure and vice versa. Humidity affects evaporation rates, and the more humid the air, the faster it evaporates. The formation of clouds is complex and requires aqueous condensation into microlitter droplets or crystals. Rainfall takes the form of rain, snow, hail, etc., and changes depend on temperature and humidity conditions. These meteorological elements work together to shape the hydrological cycle and climate characteristics of the earth's surface。
Biological evolution is the long-term result of natural selection and environmental adaptation. Darwin's biological evolution theory suggests that species are not static, but evolve through mutation and genetic variability, with natural selection. The advantages of adaptation were retained and strengthened, while those of non-adaptation were eliminated. This process has led to a high degree of fragmentation of biodiversity. Studies at the molecular biology level have found that the order of nucleotides in genetic material determines the protein sequence, thus affecting the biological form. Genetic restructuring and mutation are the main sources of genetic diversity, driving species to adapt to new environments。
The flow of materials and energy in ecosystems follows specific patterns. The material cycle refers to the recurrence of elements in the biological and abiotic environment, such as the water cycle, the carbon cycle, the nitrogen cycle, etc. Energy flows are shown to be one-way and, after input into the ecosystem from the sun, are passed down in stages through the food chain and eventually dispersed in the form of heat. The input energy is mainly used for photocosynthesis, which consumes solar energy to make organic matter; the output energy releases thermal energy mainly through respiratory action. The stability of ecosystems depends on the balance of interactions between species and energy flows, which is the basic mechanism for sustaining the evolution of the biosphere。
In astronomy, the theory of the big bang of the universe indicates that the universe originated in a high-energy event about 18,800 million years ago. At that time, the temperature was extremely high and the material was extremely dense, and then rapidly swelled and cooled. Stars are formed in gas clouds of high early density, creating new stars through gravitational collapse. The milky way system, located in the middle of its constellation, is a vortex galaxy with hundreds of billions of stars. The solar system is located in orion's spiral arm, approximately 2623,500 kilometres from the heart of the galaxy. These astronomical data help to understand the origin, evolution and future fate of the universe。
Environmental monitoring requires a combination of technical tools. Satellite remote sensing provides access to extensive surface information, such as vegetation cover, water body characteristics, etc. Ground monitoring includes meteorological stations, water quality sampling sites and soil laboratories. Data analysis uses physical models and statistical methods to process big data. Together, these approaches form a modern environmental monitoring system that provides a scientific basis for ecological conservation and pollution management。
The management of geological disasters requires the establishment of early warning mechanisms and emergency response systems. Disasters such as earthquakes, landslides and mudslides have a sudden and devastating character. Potential areas can be identified in advance through geological survey and monitoring networks. Engineering measures such as the construction of earth walls and drainage can mitigate risks, but need to be combined with ecological restoration. Public education to raise awareness of disaster prevention is a critical link in reducing casualties. These measures reflect the modern concept of living in harmony with nature。
Scientific research is subject to strict norms. Field operations should wear protective equipment and comply with safety protocols. Data recording needs to be real-time and standardized to prevent human error. Analytical methods should be validated to ensure reliability. Academic exchanges promote knowledge-sharing and promote scientific progress. These norms guarantee the quality and efficiency of research work。
The scientific spirit emphasizes rational thinking and empirical research. Faced with unknown areas, an open mind and a critical sense should be maintained. Experimental validation of assumptions supported by objective data. This mindset applies not only to the natural sciences but also to the humanities. The ability to think independently is particularly important in the era of information explosions。
