Scientific experiment refers to the application of certaininstrument, equipment and other material meansManual controlUnder the condition of the, observe and study the natural phenomenon and its regular form of social practice.It is an important way to obtain empirical facts and test the truth of scientific hypothesis and theory.It includes not only the material objects of instruments, equipment and experiments, but also the relevant social factors such as background knowledge, theoretical assumptions, data analysis, scientific interpretation, as well as the negotiation, exchange and fund acquisition between experimenters.Its nature is not only material, but also cultural and social.
In the experimental activities, isolation, intervention, tracing, instrument operation, object shape transformation, experimental condition control and resource utilization all show that the experimenter is a natural and social participant.The scope and depth of scientific experiments are constantly expanding and deepening with the development of science and technology and social progress.[1]
Scientific experiments areobservationA form of.Because scientific experiments play a special important role in empirical natural science research, scientific experiments need to be discussed separately.
When people are not satisfied with observing objects under natural conditions and require active intervention on the objects being studied, this leads to the emergence of scientific experiments.
scientific experiment
stayAncient societyScientific experiments have been gradually brewing in the process of exploring the mysteries of nature.But at that time, the experiment only appeared in the primitive and simple form, and it has not become an independent form of social practice.Scientific experiments in the strict sense began in modern times.The application of experimental methods has become the main feature of modern natural science.The fundamental reason why this situation appeared in modern times was that industrial production had been greatly developed at that time.EngelsSaid, "FromCrusadeSince then, industry has undergone tremendous development, and many new facts in mechanics (textile, watch manufacturing, mill), chemistry (dyeing, metallurgy, wine making), and physics (glasses) have emerged. These facts not only provide a large number of observable materials, but also provide completely different experimental means,And make it possible to manufacture new tools.It can be said that truly systematic experimental science is only now possible for the first time. "（《Selected Works of Marx and Engels》Volume 3 People's Publishing House, 1972 edition, pages 523-524)
From modern times to modern times, scientific experiments have experienced great development, and the sociality 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 integral part of the whole social cause.
Like scientific observation, scientific experiment is also to collect scientific facts and obtainsense data The basic method ofScientific hypothesisAnd form the practical basis of scientific theories, which are interrelated and complementary to each other.But experiment is to know nature in the process of changing nature, so it has a unique cognitive function.The reason is that the use of a variety of 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
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The scientific method should include six important steps:
observation
Observation is a detailed record of facts and events.
definition
There is an exact procedure for defining problems.
hypothesis
Putting forward a hypothesis is a temporary explanation of a thing or a relationship.
test
To collect evidence and test hypotheses, on the one hand, we should be able to provide the objective conditions required by the hypothesis, and on the other hand, we should find ways to measure relevant parameters.
publish
Publish research results: scientific information must be open and transparent, and the real concern of science is to solve problems.
construct
That is, constructivism.An isolated problem cannot establish a theory, and scientific theories can be falsified.
Experimental characteristics
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The reason why scientific experiments are valued and superior to natural observation is closely related to the characteristics of scientific experiments themselves.
Purification conditions
Scientific experiments have the function of purifying the conditions of observation objects.
Pasteur broth experiment
The objects and phenomena of nature are in a complex and universal relationship, which contains various factors.Therefore, any specific object is the unity of diversity.This situation brings difficulties in cognition, because some characteristics of the object are either covered up or interfered by other factors, so that some characteristics of the object are not easy for people to understand, or generally can not be perceived at all.In scientific experiments, people can use various experimental means to carry out various artificial changes and controls on the research objects, so that they can get rid of the interference of various accidental factors, so that the characteristics of the research objects can be exposed in their true colors.People can obtain the characteristics that are difficult to observe in the natural state of the object being studied.
For example, what causes the common phenomenon of broth corruption?PasteurIt is believed that the boiled broth deteriorated later, which is the result of microorganisms in the air entering the broth.However, under natural conditions, broth always comes into contact with the air, and there must be countless dust in the air, which carries microorganisms.Therefore, under natural conditions, it is impossible to prevent microorganisms in the air from entering the broth.So Pasteur turned to experimental purification.He designed a kind of curved neck bottle to inject broth into the bottle and heat it for sterilization.Because the bottle is curved, it makes it difficult for the dust in the outside air to enter the bottle.As a result, the broth is not corrupt.This is to eliminate the effect of microorganisms in the air on the broth through certain experimental means, and observe that the broth will not decay in a relatively pure state.
Strengthening condition
Superconductive state
Scientific experiments can strengthen the conditions of observation objects.In scientific experiments, people can use various experimental means to create special conditions that cannot or almost cannot appear in the natural state of the earth's surface, such asUltrahigh temperature, ultra-high pressure, ultra-low temperature, ultra-high pressurevacuumwait.Under such strengthened special conditions, people have encountered many new phenomena that are unknown before and are not impossible or easy to encounter in the natural state, making people discover many new facts of great significance.
For example, people can create ultra-low temperatures close to absolute zero through certain experimental means, so that we can liquefy almost all gases.At this ultra-low temperature, people can also find that some materials have special excellent electrical conductivity, that is, they have no resistance, diamagnetism, etcSuperconductive statecharacteristic.
Repeatability
Scientific experiments are repeatable.
The phenomena that occur under natural conditions are often gone forever, so it is impossible to observe them repeatedly.In scientific experiments, people can make the observed objects appear repeatedly through certain experimental means, which is not only conducive to people's long-term observation and research, but also conducive to people's repeated comparative observation and verification of previous experimental results.
Priest oxygen experiment
For example, British chemist Priestley used a condenser to heat the oxide of mercury in 1774 to decompose a gas, which is more than that of airCombustibilityBe many times stronger.Priestley calls this gas a misfire gas.When Priestley told the news to French scientist Lavoisier, Lavoisier immediately started to repeat the experiment, so that he finally found that heatingMercuric oxideThe decomposed gas that can support combustion is nothing but oxygen.
It is precisely because of these characteristics of scientific experiments that scientific experiments are more and more widely used and play an increasingly important role in modern science.In modern science, the research topics that people need to solve are increasingly complex and diverse, which makes the forms of scientific experiments increasingly rich and diverse.
Experimental classification
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There is still a lack of systematic research on the classification of benefit experiment types.We only briefly introduce the following two categories:
Qualitative experimentIt is an experiment to determine whether certain factors and properties exist.
Quantitative experimentIt is an experiment used to determine the relationship between certain values or quantities.
Structural Analysis ExperimentIt is an experiment to understand the spatial structure between various components within the subject.
By means
Experiments can be divided intoDirect experiment, indirect experiment andmodel experiment Etc.
Building daylighting model experiment
Direct experimentIt refers to the experiment in which the experimental means directly affect the subject.The model experiment is based onSimilarity principleAn experiment in which a model is used to replace the object being studied, that is, the prototype. The experimental means directly act on the model rather than the prototype.stayModern natural scienceThe model is not limited to those with the same physical properties as the prototypephysical model Instead of developing mathematical modelscyberneticsModels, etc.Mathematical modeling is based on the similarity of mathematical forms between model and prototype.The cybernetics model is based on the similarity of control functions.Therefore, people canSports formThe simulation experiment was conducted between the objects of.
By object nature
According to the diversity of the nature of experimental objects, it can be divided into physical experimentschemical experiment、Life Experiment、Human experimentEtc.
According to the transparency of the experimental object, it can be divided intoblack boxExperiment, grey 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 can not replace theoretical research;Experiments are always special, and there is always a distance between special results and general theories;Experiments can only be carried out in a limited range, and many problems cannot be studied through experiments.
Experimental procedures
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Preparation phase
Scientific experiment[2]The first stage of the process can be calledPreparation stage of 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 do four things.Each of these tasks cannot be separated from the application of theory and logical thinking activities.
Establish the purpose of the experiment
This is to make clear why we conduct the experiment.
For example,MichelsonAbout MoreyInterference of lightThe purpose of the experiment was to test whether the popular ether theory was correct.For this purpose
Michelson interferometer
Realization 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.Clarify the theory guiding experimental design。
After establishing the purpose of the experiment, we should not start to design the experiment immediately, but first clarify what theory should guide the design of the experiment.This guiding theory is to inspire the experimenter to adopt what method and from what direction to achieve the established purpose.Without this step, it is impossible to transition from experimental purpose to specific actual design.
For example,EngelsIt has long been proposed that life is throughChemical evolutionBy the way of.After Engels, many scientists wanted to test Engels' conclusions with experiments.But for a long time, people could not enter the specific experimental design.The reason is that the guiding theory on which the experiment design is based is not yet available, and people do not know where to start designing this experiment.In other words, there is still a lack of an intermediate link between the experimental purpose and the specific experimental design.
In the 20th century, people put forward a theory: under the original atmospheric conditions different from today, in the long years, nonliving 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 direction.People can further make logical reasoning based on these theories: suppose we simulatePrimitive EarthOfAtmospheric composition, and create the corresponding conditions, then we can carry out the experiment of simulating the primitive earth period to transform inorganic substances into organic substances necessary for life.1953MillerOur experiment is designed according to this guiding theory and has achieved success.The guiding theory is not only related to the question of where an experimental purpose should be achieved, but also directly affects the effectiveness of experimental design.
Start experiment design
Drug effect experiment
Marx said: "The ability of bees to build beehives has made many architects in the world feel ashamed. However, the worst architect is better than the most dexterous bee from the beginning. It is he who built the beehives in his own mind before building them with beeswax.The results obtained at the end of the labor process already exist in the workers' appearance at the beginning of the process, that is, they already exist conceptually. "（《Complete Works of Marx and Engels》Volume 23, People's Publishing House, 1972 edition, page 202) This means that people should first consider how they should act in the future, what steps they should take, what results each step may bring, and what impact it will have if certain conditions suddenly change.Scientific experiment is a kind of social practice that people carry out to change the objects of nature in order to understand the nature.Of course, before taking concrete experimental actions, people should roughly complete the action process of this change in the form of ideas in their thinking.Which interference factors should be eliminated and which secondary factors should be temporarily ignored should be considered in the experimental design.The task of experiment design is to complete the experiment in your own ideas before implementing the experiment.Experimental design is a process of logical inference using certain theories.The advantages and disadvantages of experimental design largely depend on whether the logical thinking in the design process is rigorous.For example, in the experiment design, we should 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 for example, when designing the experiment, we should consider that if the patient knows that it is a drug effect experiment, his psychological reaction may affect his physiology, thus making the experiment deviate. If a doctor knows which patients areexperience groupWhich patients belong to the control group, then their psychological reaction may also affect the diagnosis, thus causing deviation in the experiment.Therefore, strict measures should be taken in the experimental design to eliminate the influence of this accidental factor on the experimental effect.These thinking processes are all logic analysis and logic reasoning processes based on certain theories.
Of course, there are many specific technological and technical problems in the experimental design.However, the main line that runs through the experimental design is the logical inference based on certain theories.The corresponding process and technical problems can only be connected into a complete design on the basis of certain logical thinking.
Experiment preparation
Mendel pea experiment
People tend to 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 certain theories.For example, GalileoToriThe thermometers used by Charlie and others are made on the assumption that the liquid and gas expand proportionally with the "degree of heating".In 1878, the resolution of the International Commission on Weights and Measures on standard thermometers stipulated as follows: "The temperature shall be measured with chemically pure hydrogenConstant volumeThe pressure at the melting point of ice is 1000mm high.Therefore, every instrument adopted actually means the introduction of some theories.The selection of materials is also based on certain theories.
For example,MendelPeas were selected as experimental materials because of their strict self pollination, easy cultivation, short growth period, and obvious distinguishable traits.Without certain theoretical and logical thinking, the preparation of experimental instruments, equipment and materials cannot be carried out.
implementation phase
The second stage of scientific experiments can be calledImplementation phase of the experiment。
In this stage, the experimenter operates certain instruments and equipment to act on the experimental object to obtain certain experimental effects and data.The interaction between instruments and experimental objects is a regular manifestation that does not depend on human will.Therefore, the activity at this stage is an objective material activity.As an objective perceptual material activity, the experiment implementation process is the test of people's existing knowledge, and also provides new facts for people to understand.
Result processing stage
The third stage of scientific experiments can be calledProcessing stage of experimental results。
At this stage, people analyze the experimental results.Because although people have made careful consideration in the experiment design, there will still be some subjective and objective factors that have not been estimated in advance during the implementation of the experiment.The so-called objective factors mainly refer to the accidental changes of experimental instruments and equipmentinitial condition Accidental changes in environmental conditions, some differences in varieties and specifications of experimental materials, etc.The so-called subjective factors mainly refer to the missing consideration of some possible system errors in the experimental design, the sensory bias in reading data, and so on.The impact of these factors is mixed.Therefore, people must analyze the results of the experiment initially to distinguish what should be eliminated and what should be the results of the experiment.
In scientific experiments, people are changing the objective material object, which makes it have the same aspects as people's production activities.Because production activity, as an activity that people actively transform the objective world, is also an activity that changes material objects.Because of this, scientific experiments, like production activities, belong to the category of practical activities to transform the objective world and become a basic form of practice.But there are differences between scientific experiments and production activities.
First, they have different direct purposes.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 they need for life and reproduction.
Newton
Secondly, they produce different results.The result of scientific experiments is that people have gained knowledge of facts and tested certain theories.The result of production activities is that people get the products they need.Of course, this difference is not absolute.Especially in modern times, scientific experiments and production activities have obviously infiltrated each other.The development of production provides the premise 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 problems in production and become part of production activities. Many production activities have the nature of scientific experiments, which also answer some scientific research topics while producing material products.On the relationship between scientific experiments and production activities, this isSociology of ScienceIt is an important subject of research.
The experimental method refers to the method of determining the relationship between things under human control through special arrangementsresearch method。Experimental method is one of the earliest research methods widely used in the field of natural science researchModern Natural ScienceSome foreign scholars believe that research is a process of experiment, experiment, re experiment and repeated search.Da VinciGalileoNewtonPeople have made great scientific achievements by making full use of experimental methods.
Experimental composition
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No matter what kind of scientific experiments, they are composed of three parts.
Experimenter
This is the person who organizes, designs and conducts scientific experiments.No link can be separated from the experimenter in the determination of experiment purpose, the design of experiment scheme, the formulation of experiment steps, the operation of experiment process, the processing and interpretation of experiment results, etc.The experimenter is the main body of experimental activities.Experimenters engage in scientific experiments to gain knowledge of specific objects in nature.Without the subject of knowledge of the experimenter, scientific experiments would not occur.However, it should be pointed out here that the experimenter cannot be understood as an isolated individual.In any case.The experimenters are not acting as isolated individuals, but as social people.The experimenter inherits the positive achievements made by the predecessors, also draws on the successful experience and failure lessons of the same era, and also relies on the collaborative work among people in all aspects.Therefore, any beneficial results obtained by the experimenter will be integrated into the overall social spiritual wealth.In this way, it is not to deny the individual creative ability of the experimenter, but to say that this creative ability can be brought into play only when it is not separated from the basis of society.
Subjects
This is what the experimenter needs to know.Experimental objects can be natural objects and phenomena, 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 for the experimenter to change and control, but also the object for the experimenter to understand.Therefore, from the epistemological point of view.The experimental object is in the position of cognitive object.
Experimental means
The experimental means areExperimental instrument、tool、equipmentAnd other objective material conditions,Experimental instrumentIs the main component.
The role of experimental means is mainly manifested in two aspects:
On the one hand, the experimenter transfers his intention to change and control the experimental object to the experimental object through experimental means, so that the experimenter's intention can be materialized.
On the other hand, the experimental means show the characteristics of the experimental object, and transmit the state of the experimental object after undergoing change and control to the experimenter, so that the experimenter can obtain relevant knowledge about the experimental object.
Therefore, experimental means are the intermediary link between the experimenter and the experimental object.Without proper experimental means, some characteristics of the experimental object cannot be exposed, and people cannot gain knowledge of these characteristics.
In this sense, the state of experimental means determines the level of understanding that scientific experiments can achieve.Every step of improvement of experimental means means an increase in people's observable observation of experimental objects and the improvement of scientific experiment level.It can be seen from the history of science that the adoption of new experimental means often brings about major breakthroughs and developments in scientific theory.Therefore, it is a strategic measure to consciously improve the experimental means.However, the experimental means of an era were also the concrete expression of the productivity level of that era, which was restricted by the development of productivity at that time.Therefore, the improvement of experimental means and the equipment of new experimental means can only be realized with the improvement of the productivity level of the whole society.
model experiment After it came into being, people experimented with models instead of prototypes.What part does the model belong to in the structure of scientific experiments?In scientific experiments, models have dual properties.As far as the model is the object that the experimenter uses experimental means to carry out actual change and control, the model is the experimental object.The experimenter carries out various experiments on the model, so as to obtain various understandings about the model.However, as far as the model is only a substitute for the prototype, the real purpose of the experimenter is to obtain knowledge about the prototype. The real object of the experiment is the prototype, while the model is still the experimental means used by the experimenter.This is an expanded means.Perhaps it is precisely because of this dual nature of the model that it occupies a particularly important position in scientific experiments.
Experimental effect
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Simplification and purification
The experimental method can make use of the conditions caused by scientific instruments and equipment, according to the research purpose, highlight the main factors of the research object, eliminate secondary factors, accidental factors and external interference, so that some attributes of the things to be known can be displayed in a specific state, so that the essence and laws of things can be more accurately understood.For example, in 1799, the British physicist Henry David kept the experimental instruments in waterfreezing pointThe heat exchange between the experimental objects and the surrounding environment was excluded, which proved that the heat needed for ice melting came from friction, and denied the dominant "heat element theory" at that time.
Strengthen or weaken
Superconductor
Many things can not fully expose their essence under normal conditions. Experiments can create an environment that is impossible to appear in nature, so as to better understand the research object.For example, Dutch scientists in 1911Onnis When the temperature of mercury is lowered below O'C, it is found that the resistance of mercury suddenly disappears and becomes the so-called superconductor, which opens the door to superconductivity research.American scientistWu JianxiongCobalt-60 was put in the extreme state of ultra-low temperature, and successfully verifiedWeak interactionThe assumption that the lower parity is not conserved.
Natural process
Many things in nature are fleeting, some take a long time, and some have changed, 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 the control of human beings.1953 American scientistMillerExperiments on the earth's atmosphere and lightning are carried out. He imitates the natural conditions of the earth's lightning and conducts experiments on various gases put into the vacuum tubeSpark discharge。After eight days of repeated action, five important amino acids that make up the protein were finally obtained, and this process would take hundreds of millions of years in the natural state.
Experimental principles
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Master theory
Be familiar with the theory and experience related to the experimental subject.
Experimental method is a process of conducting research on the research object under artificial control, so it is necessary to carefully design the experimental scheme.In the process of designing experimental schemes and conducting specific experiments, theoretical guidance and the accumulation of previous experience are indispensable.The experimenter only has the necessaryTheoretical knowledgeAnd experimental skills, we can have a keen observation of new things in the experiment. When things appear beyond the original theoretical framework, we can catch them in time and discover their essence.
suggest a hypothesis
Peptide chain
Hypothesis or opinions and theories that need to be tested shall be put forward in advance.Experiments have two main purposes in scientific research: one is to explore and discover new phenomena or laws;The second is to test the correctness of existing knowledge or theory.
From 1902 to 1907, German chemist Fischer conducted in-depth research on the chemical conclusion of protein, proposed the peptide bond theory of protein, and then synthesized 18 amino acidspolypeptideLong chain to verify its reflectionprotein structureThe correctness of the theory.
Well designed
It shall be carefully designed and organized.
As the saying goes, "Knowing oneself and the enemy is the best way to win a hundred battles".The experiment to be done must be carefully designed, closely organized, and well understood, so that the success rate can be greater.According to certain theories and specific research objects, different research methods can be adopted.For example, Taylor has put forward scientific management methods through careful design and strict organization, using experiments of moving iron blocks, mining experiments of iron sand and coal, metal cutting experiments, etc.
make preparation
The experimental environment should be selected and the experimental tools should be prepared.
Butyl particle
The experimental environment has a great relationship with the success of the experiment. For example, when observing celestial bodies, it is necessary to choose good weather to achieve ideal results.
The routine state of the subject shall be maintained.
Regardless of whether the research object is a thing in the nature or a human being, in order to maintain the objectivity of the experimental results, we should try to maintain the regular state of the subject.Only in the normal state, what things or people show is their true situation.Under normal conditions, Mayo improved working conditions and environmentWelfare Experiment, telephone coil assembly experiment, interview experiment, etc.
Control factors
It shall be able to effectively control various factors affecting the experiment.
Galileo falling body experiment
During the experiment, we should try to control various factors in the experiment according to the research purpose.It is necessary to highlight the main factors, eliminate secondary factors, accidental factors and external interference, so as to understand the essence of things more accurately.Galileo's falling body experiment, inclined plane experiment andSimple pendulum experimentThe success was achieved under the condition that the main factors were highlighted and the secondary factors were eliminated.
Observe carefully
Careful observation should be made to obtain accurate data as far as possible.
In the history of science and technology, some scientists often regret when some important discoveries are published, because they have seen similar phenomena before, but they lost the great opportunity of discovery because they did not pay attention.FrenchCurie, JorioIn use.Particle bombardmentBerylliumneutron, but he didn't pay attention and mistook it forY particle, let it slip away.Later,ChadwickIt is proved that it is not gamma ray but neutronThe nobel prize in physics。It can be seen that in the process of scientific experiments, only careful observation can achieve ideal results.
Repeated experiment
Experiments should be repeated from small to large.
Gravitational wave
Generally speaking, before doing in-depth large-scale experiments, we need to do some exploratory experiments, which are simple first and then complex, so that we can accumulate relevant information and ideas for future experimental work.The experiment should pay attention to its repeatability.Only repeated times can show that the results can be recognized by everyone.1959 American physicistweberHe once announced that his experimental device had directly received theGravitational radiation, directly verifiedEinsteinA prediction about gravitational waves.However, its experiments could not be repeated in more than a dozen laboratories in the world, so it was not recognized by the scientific community.
Check conclusion
The conclusions drawn after the experiment should be carefully checked.
After the experiment, the data obtained in the experiment should be further processed and sorted outScientific factsOr some regular theory.In the process of analysis, it is necessary to use statistical analysis methods and computer and other means to deal with the causal relationship, origin relationship, functional relationship, structural relationship and other aspects and levels of data.
