Basic information
Scientific experiment is a form of observation. Because scientific experiments have a particularly important position in empirical natural science research, it is necessary to separately discuss scientific experiments.
When people are not satisfied to observe the object under natural conditions and require active intervention on the object under study, this leads to the emergence of scientific experiments.
In ancient society, scientific experiments have been gradually brewing in the process of people exploring the mysteries of nature. But the experiment at that time only appeared in a primitive and simple form, and it has not yet become an independent form of social practice. Strictly speaking, scientific experiments began in modern times. The application of experimental methods has become the main feature of modern natural science. The fundamental reason why this kind of situation appeared in modern times is that industrial production has developed by leaps and bounds at this time. Engels said: "Since the Crusades, industry has developed tremendously, and many mechanical (textiles, watchmaking, mills), chemical (dying, metallurgy, winemaking), and physical ( Glasses) new facts. These facts not only provide a large amount of materials for observation, but also provide experimental methods completely different from the past, and make it possible to manufacture new tools. It can be said that a truly systematic experimental science, It was only then that it became possible for the first time." (The Selected Works of Marx and Engels, Vol. 3, People's Publishing House, 1972 Edition, pp. 523-524)
From modern times to modern times, scientific experiments have undergone great development. , The social nature of scientific experiments has gradually improved. After the 1940s, the scale of scientific experiments became larger and larger. Scientific experiments are no longer the career of individual scientists, but an organic part of the entire social career.
Scientific experiments, like scientific observations, are also a basic method for collecting scientific facts and obtaining perceptual materials. At the same time, they are also used to test scientific hypotheses and form a practical basis for scientific theories. The two are interrelated and complement each other. But experiment is to understand nature in changing nature, so it has a unique cognitive function. The reason is that the use of multiple instruments in scientific experiments makes the obtained perceptual materials richer and more accurate, and can eliminate the interference of secondary factors, and reveal the essence of the research object faster.
Main steps
The scientific method should include six important steps:
Observation
Observation is the detailed record of facts and events .
Definition
There is a precise procedure for defining a problem.
Hypothesis
Proposing a hypothesis is a temporary explanation of a thing or a relationship.
Test
Collect evidence and test hypotheses. On the one hand, it must be able to provide the objective conditions required for the hypothesis, and on the other hand, it must find methods to measure relevant parameters.
Publishing
Publishing research results: Scientific information must be open and transparent, and the real scientific focus is on solving problems.
Construction
It is the construction theory. Isolated problems cannot establish a theory, and scientific theories can be falsified.
Characteristics of experiments
The reason why scientific experiments are valued by people and their superiority to natural observations is closely related to the characteristics of scientific experiments.
Purification conditions
Scientific experiments have the function of purifying the conditions of observation objects.
The objects and phenomena in nature are in intricate and universal connections, and various factors are contained in them. Therefore, any specific object is the unity of multiple auspiciousness. This situation brings about difficulties in understanding, because some characteristics of the object are either concealed or interfered by other factors, so that some characteristics of the object are either difficult for people to understand clearly, or it is normal. You can't notice it at all. In scientific experiments, people can use various experimental methods to carry out various artificial changes and control on the research object, so as to get rid of the interference of various accidental factors, so that the characteristics of the research object can be purely original. And exposed. People can obtain characteristics that are difficult to observe in the natural state of the researched object.
For example, what causes the common phenomenon of broth corruption? Pasteur believes that the boiled broth deteriorated later, as a result of microorganisms in the air entering the broth. However, under natural conditions, the broth is always in contact with the air, and there are bound to be countless dust in the air, and the dust carries microorganisms. Therefore, under natural conditions, it is impossible to prevent microorganisms in the air from entering the broth. So Pasteur turned to the purification effect of the experiment. He designed a retort in which broth was poured into the bottle and heat sterilized. Because the bottle has a curved neck, it makes it difficult for dust in the outside air to enter the bottle. As a result, the broth is not spoiled. This is through certain experimental methods, eliminating the effect of microorganisms in the air on the broth, and it has been observed that the broth will not spoil in a relatively pure state.
Strengthening the conditions
Scientific experiments have the effect of strengthening the conditions of the observation objects. In scientific experiments, people can use various experimental methods to create special conditions that can't appear or almost can't appear in the natural state of the earth's surface, such as ultra-high temperature, ultra-high pressure, ultra-low temperature, ultra-vacuum and so on. Under this strengthened special condition, people have encountered many previously unknown new phenomena that cannot or are not easy to encounter in the natural state, and people have discovered many new facts of great significance.
For example, people can create ultra-low temperatures close to absolute zero through certain experimental methods, so that we can liquefy almost all gases. At this ultra-low temperature, people can also find that some materials have special and excellent electrical conductivity, that is, they have superconducting properties such as non-resistance and diamagnetic properties.
Repeatability
Scientific experiments are reproducible.
Phenomena that occur under natural conditions are often gone forever, so it is impossible to observe them repeatedly. In scientific experiments, people can use certain experimental methods to make the observed objects reappear. This is not only conducive to long-term observation and research, but also conducive to repeated comparison and observation, and to check the results of previous experiments.
For example, the British chemist Priestley used a condenser to heat the oxide of mercury in 1774 to decompose a gas, which is many times stronger than air for combustion. Priestley refers to this gas as lost combustion gas. When Priestley told the French scientist Lavoisier of the news, Lavoisier immediately repeated the experiment, and he finally discovered that the combustible gas decomposed by heating the mercury oxide was not other but oxygen.
It is precisely because of these characteristics that scientific experiments have been applied more and more widely, and they have become more and more important in modern science. In modern science, the research topics that people need to solve are becoming more and more complex and diversified, which makes the forms of scientific experiments continue to be enriched and diversified.
Experiment classification
There is still a lack of systematic research on the classification of experimental types. We only briefly introduce the following two categories:
According to the purpose of the experiment
According to the purpose of the experiment, scientific experiments can be divided into qualitative experiments< b>,Quantitative experiment and Structural analysisExperiment.
Qualitative experiment is an experiment used to determine whether certain factors and properties exist.
Quantitative experiment is an experiment used to determine the relationship between certain values or quantities.
Structural analysisExperiment is an experiment used to understand the spatial structure of various components within the researched object.
According to means
According to whether the experimental means (instruments, equipment tools, etc.) directly act on the researched as the standard, the experiment can be divided into direct experiment, Indirect experiments andmodel experimentsetc.
Direct experiment is an experiment in which experimental methods directly affect the subject. A model experiment is an experiment in which a model is used to replace the researched object, that is, a prototype, based on the principle of similarity, and the experimental method is directly applied to the model instead of the prototype. In modern natural sciences, models are no longer limited to physical models with the same physical properties as prototypes, but mathematical models, cybernetic models, and so on have been developed. The mathematical model is based on the similarity of the mathematical form of the model and the prototype. The cybernetic model is based on the similarity of control functions. Therefore, people can conduct simulation experiments between objects with different forms of motion.
According to the nature of the object
According to the diversity of the nature of the experimental object, it can be divided into physical experiments, chemical experiments, life experiments, human experiments, etc.
According to the predetermined purpose
According to the predetermined purpose of the experimenter, it can be divided into qualitative experiment, quantitative experiment, measurement experiment, control experiment, confirmatory experiment, judgment experiment and intermediate experiment.
According to the experiment object
According to the transparency of the experiment object, it can be divided into black box experiment, gray box experiment and white box experiment.
In addition, researchers should make full use of experimental methods to study specific things, but must understand the limitations of experimental methods, such as experiments cannot replace theoretical research; experiments are always special, special results and universal There is always a distance between theories; experiments can only be carried out within a limited range, and many problems cannot be studied through experiments.
Experimental procedure
Preparation phase
The first phase of the scientific experiment process can be called the preparation phase of the experiment.
The value of a scientific experiment, its success or failure, largely depends on the preparation stage of the scientific experiment. At this stage, people need to perform four tasks. Each of these tasks cannot be separated from the application of theory, and cannot be separated from logical thinking activities.
Establish the purpose of the experiment
This is to clarify why we are experimenting.
For example, the purpose of Michelson and Morey’s interference experiment on light was to test whether the prevailing ether theory was correct. The realization of this purpose plays a very important role in promoting the development of physics. Determining the purpose of the experiment is a process of logical deduction of theory. Clearly guide the theory of experimental design.
After the purpose of the experiment is established, it is not possible to design the experiment immediately, but it is necessary to clarify what theory is used to guide the design of the experiment. This guiding theory is to inspire experimenters what methods should be used and in what direction to achieve established goals. Without this step, it is impossible to transition from the experimental purpose to the specific actual design.
For example, Engels has long proposed that life is produced through chemical evolution. After Engels, many scientists wanted to use experiments to test Engels's thesis. But for a long time, people could not enter the specific experimental design. The reason is that the guiding theories on which the experimental design is based are not yet available, and people do not yet know where to start to design such experiments. In other words, there is still a lack of an intermediate link between the purpose of the experiment and the specific experimental design that connects the two.
After entering the 20th century, people came up with a theory: Under primitive atmospheric conditions different from today, in the long years, non-living matter can be transformed into life. Later, Hayden put forward the concept of primitive atmosphere and primitive soup. After these theories were put forward one after another, the experimental design had a basis and a direction. People can make further logical inferences based on these theories: Assuming that we simulate the atmospheric composition of the primitive earth and create the corresponding conditions, then we can carry out experiments that simulate the transformation of inorganic matter into organic matter necessary for life during the primitive earth period. Miller's experiment in 1953 was designed and succeeded based on this guiding theory. Guiding theory is not only related to the question of where an experimental goal should be realized, but also directly affects the effectiveness of experimental design.
Start experimental design
Marx said: "The ability of bees to build hives makes many architects in the world feel ashamed. However, the most crappy architect is better than the most dexterous from the beginning. The wise point of the bee is that he had built the hive in his own mind before using beeswax to build it. The result obtained at the end of the labor process was already present in the appearance of the laborer at the beginning of the process. It already exists conceptually.” (The Complete Works of Marx and Engels, Volume 23, People's Publishing House, 1972 Edition, p. 202) This means that people must first consider how they should act in the future before taking actual actions. Which steps, what results each move may bring, if certain conditions suddenly change, what effects will happen, and so on. Scientific experiment is a kind of social practice activity that people carry out to change the objects of nature in order to understand the natural world. Of course, before taking concrete experimental actions, people have to roughly complete the process of transformation in their thinking in conceptual form before taking concrete experimental actions. Which interfering factors should be eliminated, and which secondary factors should be temporarily set aside, all these should be considered in the experimental design. The task of experimental design is to complete the experiment in one's own concept before implementing the experiment. Experimental design is the process of using a certain theory to make logical inferences. The pros and cons of experimental design largely depend on whether the logical thinking in the design process is rigorous. For example, in experimental design, we must carefully consider what contingency factors may occur in the implementation of the experiment, and what impact these contingency factors will have on the experimental effect. Take the experiment of a certain drug effect as an example. When designing the experiment, it is necessary to consider that if the patient knows that he is doing a drug effect experiment, then his psychological reaction may affect the physiology, and the experiment will be biased. If a doctor knows which patients belong to the experimental group and which patients belong to the control group, then his psychological reaction may also affect the diagnosis, which will bias the experiment. Therefore, corresponding strict measures must be taken in the experimental design to eliminate the influence of such accidental factors on the experimental effect. These thinking processes are processes of logical analysis and logical reasoning using certain theories.
Of course, there are many specific process and technical issues in the experimental design. But the main thread that runs through the experimental design is the use of a certain theory to make logical inferences. Corresponding process and technical issues can only be combined into a complete design on the basis of certain logical thinking.
Experiment preparation
People often regard the preparation of experimental instruments, equipment, and materials as a purely physical activity. In fact, every instrument is designed and manufactured on the basis of a certain theory or some theory. For example, the thermometers used by Galileo, Torricelli, and others are made based on the assumption that liquids and gases expand in proportion to the degree of heating. The 1878 International Committee for Weights and Measures resolution on standard thermometers stipulated as follows: "The temperature should be measured by the pressure of chemically pure hydrogen at a constant volume, and its pressure at the melting point of ice is 1000 mm mercury column height." . Therefore, every time an instrument is adopted, it actually means the introduction of some theories. The selection of materials is also based on a certain theory.
For example, Mendel chose peas as experimental materials because peas have strict self-pollination, are easy to cultivate, have a short growth period, and have obvious distinguishable traits. Without certain theoretical and logical thinking, the preparation of experimental instruments, equipment, and materials cannot be carried out.
Implementation stage
The second stage of the scientific experiment can be called the implementation stage of the experiment.
At this stage, the experimenter operates certain instruments and equipment to make it act on the experimental object in order to obtain certain experimental effects and data. The interaction between the equipment and the experimental object is a regular expression that does not depend on human will. Therefore, the activity at this stage is an objective material activity. The experimental implementation process as an objective perceptual material activity is a test of people's existing knowledge, and it also provides people with new facts.
Results processing stage
The third stage of scientific experiments can be called the processing stage of experimental results.
At this stage, people analyze the results of the experiment. Because although people have made careful consideration in the experimental design, there are still some subjective and objective factors that have not been estimated beforehand that affect the experimental results. The so-called objective factors mainly refer to accidental changes in experimental equipment, initial conditions of the experiment, accidental changes in environmental conditions, and certain differences in the specifications of the experimental materials. The so-called subjective factors mainly refer to the omission of consideration of some possible systematic errors in the experimental design, the deviation caused by the senses when reading the data, and so on. The effects of these factors are mixed together. Therefore, people must analyze the initial results of the experiment to distinguish between the error that should be eliminated and the result that the experiment should have.
In scientific experiments, people change objective material objects, which makes it have the same aspects as people’s production activities. Because production activity, as an activity for people to actively transform the objective world, is also an activity for changing material objects. It is precisely because of this that scientific experiments, like production activities, belong to the category of practical activities that transform the objective world, and become a basic form of practice. However, there are differences between scientific experiments and production activities.
First of all, their direct purpose is different. The direct purpose of scientific experiments is to solve certain scientific research tasks. The direct purpose of production activities is to provide people with the material wealth needed for life and reproduction.
Secondly, they produce different results. The result of scientific experiments is that people gain knowledge of facts and test certain theories. The result of production activities is to enable people to obtain the products they need. Of course, this distinction is not absolute. Especially in modern times, scientific experiments and production activities have clearly penetrated each other. The development of production provides prerequisites and conditions for scientific experiments, and scientific experiments point out the direction and open the way for the development of production. Not only that, many scientific experiments directly solve production problems and become part of production activities, and many production activities have the nature of scientific experiments. They also answer certain scientific research topics while producing material products. Regarding the interrelationship between scientific experiments and production activities, this is an important subject in the study of the sociology of science.
Experimental method refers to the research method of determining the relationship between things under human control through special arrangements. Experimental method is one of the earliest research methods commonly used in the field of natural science research. It is the foundation of modern natural science. Some scholars abroad actually believe that research is experiment, experiment, re-experiment, repetition (re) The process of searching. Da Vinci, Galileo, Newton and others all made great scientific achievements by making full use of experimental methods.
Experiment composition
No matter what type of scientific experiment, they are composed of three parts.
Experimenter
This is the person who organizes, designs, and conducts scientific experiments. The determination of the purpose of the experiment, the design of the experimental plan, the formulation of experimental procedures, the operation of the experimental process, the processing and interpretation of experimental results, etc., none of the links can be separated from the experimenter. The experimenter is the subject of experimental activities. Experimenters engage in scientific experiments in order to gain an understanding of specific objects in nature. Without the subject of knowledge as the experimenter, scientific experiments would not happen. However, it should be pointed out here that the experimenter cannot be understood as an isolated individual. in any case. The experimenters are not active as isolated individuals, but as social people. The experimenters inherit the positive results that their predecessors have established, and also draw lessons from the successes and failures of their contemporaries. At the same time, they rely on all aspects of collaborative work between people. Therefore, any beneficial results obtained by the experimenters will be integrated into the totality of social spiritual wealth. This is not to deny the experimenter’s personal creative ability, but to say that this creative ability can only be brought into play when it is not separated from the foundation of society.
Experimental object
This is the object that the experimenter wants to know. The experimental objects can be objects and phenomena in nature, such as sunlight, or objects and phenomena produced by people, such as machine tools and cloth. However, no matter what kind of experimental object, it is not only the object of experimenter's reform and control, but also the object of experimenter's cognition. Therefore, from an epistemological point of view. The experimental object is in the position of cognition object.
Experimental means
Experimental means are objective The composition of material conditions, experimental equipment is the main component.
The role of experimental methods is mainly manifested in two aspects:
On the one hand, the experimenter transmits his intention to change and control the experimental object to the experimental object through the experimental method, so that the experimenter The intention was materialized.
On the other hand, the experimental methods show the characteristics of the experimental objects, and the state of the experimental objects after undergoing changes and control is passed to the experimenters, so that the experimenters can obtain relevant knowledge about the experimental objects.
So, the experimental method is the intermediary link between the experimenter and the experimenter. Without proper experimental methods, certain characteristics of the test subjects cannot be exposed, and people cannot gain knowledge of these characteristics.
In this sense, the status of experimental methods determines the level of understanding that scientific experiments can achieve. Every step of improvement in experimental methods means an increase in people's observable amount of experimental objects and an improvement in the level of scientific experiments. It can be seen from the history of science that the adoption of new experimental methods often brings major breakthroughs and developments in scientific theories. Therefore, consciously improving experimental methods is a strategic measure. However, the experimental methods of an era are a concrete manifestation of the level of productivity of that era, and are constrained by the state of development of productivity at that time. Therefore, the improvement of experimental methods and the equipment of new experimental methods can only be achieved with the improvement of the level of productivity of the entire society.
After the model experiments were produced, people used models instead of prototypes for experiments. So which part does the model belong to in the structure of the scientific experiment? In the scientific experiment, the model has a dual nature. As far as the model is the experimenter's use of experimental means to carry out the actual transformation and control of the object, the model is the experimental object. The experimenter conducts various experiments on the model to obtain various understandings about the model. But as far as the model is only a substitute for the prototype, and the experimenter’s real goal is to gain knowledge about the prototype, the real object of the experiment is the prototype, and the model is still the experimental method used by the experimenter. This is an extended method. Perhaps it is precisely because of the dual nature of the model that it occupies a particularly important position in scientific experiments.
Experimental effects
Simplification and purification
Experimental methods can use the conditions created by scientific instruments and equipment, highlight the main factors of the research object according to the research purpose, Excluding secondary factors, accidental factors, and external interference, so that certain attributes of the things to be understood can be displayed in a specific state, so that the essence and laws of things can be understood more accurately. For example, in 1799, the British physicist Henry David kept the experimental instrument at the freezing point of water, eliminating the heat exchange between the experimental object and the surrounding environment, proving that the heat required for melting ice comes from friction, denying the dominant position at the time. Resu said".
Strengthen or weaken
Many things do not fully expose their essence under normal conditions. Experiments can create environments that are impossible in nature to better understand the research objects. For example, in 1911, when the temperature of mercury dropped below O'C by the Dutch scientist Onnis, he discovered that the resistance of mercury suddenly disappeared and turned into a so-called superconductor, thus opening the door to superconductivity research. American scientist Wu Jianxiong put cobalt-60 in the extreme state of ultra-low temperature and successfully verified the hypothesis of parity non-conservation under weak interaction.
Natural process
Many things in nature are fleeting, some are long-lasting, and some are transient, which brings difficulties to people's understanding of certain things. The experimental method can change the state of things in nature according to the needs of research under artificial control. In 1953, American scientist Miller conducted experiments on the earth's atmosphere and lightning. He imitated the natural conditions of the earth's thunder and lightning to discharge various gases in a vacuum tube. After eight days of repeated action, five important amino acids that make up proteins are finally obtained. This process takes hundreds of millions of years in the natural state.
Experimental principles
Master theories
Should be proficient in the theories and experience related to the experimental subjects.
Experimental method is a process of researching the research object under artificial control, so it is necessary to design the experimental plan carefully. In the process of designing experimental programs and conducting specific experiments, it is inseparable from theoretical guidance and accumulation of previous experience. Experimenters must have the necessary theoretical knowledge and experimental skills to have a keen observation of the new things that appear in the experiment. When the performance of things exceeds the original theoretical framework, they can catch them in time and discover their essence.
Propose a hypothesis
Have a hypothesis or a point of view or theory that needs to be tested in advance. Experiments have two main purposes in scientific research: one is to explore and discover new phenomena or new laws; the other is to test the correctness of existing knowledge or theories.
From 1902 to 1907, German chemist Fisher conducted in-depth research on the chemical conclusions of proteins and proposed the peptide bond theory of proteins, and then synthesized a long polypeptide chain of 18 amino acids in the experiment. This verifies the correctness of the theory of protein structure.
Elaborate design
Should be carefully designed and tightly organized.
As the saying goes, "Knowing yourself and the enemy can survive a hundred battles." The experiment to be done must be carefully designed, tightly organized, and know well, so that the success rate can be greater. According to a certain theory, combined with specific research objects, different research methods can be adopted. For example, Taylor has proposed scientific management methods through careful design and strict organization, using iron block experiments, iron sand and coal excavation experiments, and metal cutting experiments.
Be prepared
The experiment environment should be selected and the experiment tools should be prepared.
The experimental environment has a lot to do with the success of the experiment. For example, when observing celestial bodies, you must choose when the weather is good to achieve the desired results.
As the saying goes, "knife sharpening does not cut wood by mistake", experimental tools are a key aspect of the experiment to achieve results. Its condition determines the level of understanding that the experiment can reach. If there is no high-resolution spectral food, the fine structure of the atomic spectrum cannot be understood. It is precisely because Ding Zhaozhong has continuously improved the accuracy of his experiments that he finally discovered the Ding particle.
Maintain state
The subject’s regular state should be maintained.
Regardless of whether the research object is something in nature or human beings, in order to maintain the objectivity of the experimental results, try to maintain the subject’s regular state. Only under normal conditions can things or people show their true conditions. While maintaining a normal state, by improving working conditions and environmental factors, Mayo put forward a people-oriented management thought through lighting experiments, welfare experiments, telephone coil assembly experiments, and interview experiments.
Control factors
Should be able to effectively control various factors that affect the experiment.
During the experiment, it is necessary to control various factors in the experiment as far as possible according to the research purpose. It is necessary to highlight the main factors, eliminate secondary factors, accidental factors and external interference, so as to be able to more accurately understand the essential laws of things. Galileo's falling body experiment, inclined plane experiment and simple pendulum experiment were all successful under the condition of highlighting the main factors and excluding the secondary factors.
Careful observation
Should be carefully observed to get as accurate data as possible.
In the history of science and technology, when some major discoveries are announced, some scientists often regret it, because they have seen similar phenomena, but because they did not pay attention, they lost the great opportunity of discovery. Joliot Curie of France is using it. When the particle bombarded the beryllium, it shot a neutron, but he didn't pay attention and mistaken it for the Y particle and let it slip away. Later, Chadwick proved that it is not gamma rays but neutrons, and won the Nobel Prize in Physics. It can be seen that only by careful observation in the process of scientific experiments can the ideal results be obtained.
Repeated experiments
The experiment should be repeated many times from small to large.
Generally speaking, before doing in-depth large-scale experiments, do some exploratory trial experiments, first simple and then complex, so that you can accumulate relevant information and ideas for future experimental work. Pay attention to the repeatability of the experiment. Only repeated repetitions can show that the results can be recognized by everyone. In 1959, the American physicist Weber announced that his experimental device had directly received gravitational radiation emitted from a body in the Milky Way, which directly verified Einstein's prediction of gravitational waves. However, its experiments have not been repeated in more than a dozen laboratories in the world, and therefore have not been recognized by the scientific community.
Check conclusions
Carefully check the conclusions drawn after the experiment.
After the experiment is over, the data obtained in the experiment should be further processed and sorted out to extract scientific facts or some regular theories. In the analysis process, it is necessary to use statistical analysis methods, with the aid of computers and other means to process the data from multiple angles and levels, such as the causal relationship, origin relationship, functional relationship, and structural relationship between the data.