高中生物新课程中对照实验和对比实验的例谈（A case study of controlled experiment and comparative experiment in new biology course in Senior High School）A case study of controlled experiment and comparative experiment in new biology course in Senior High SchoolWang Qiong (Feidong No.1 middle school, Anhui 231600)[Abstract] this paper gives an example to analyze what is a contrast experiment and a contrast experiment, thus further explaining the difference and connection between the contrast experiment and the contrast experiment.[Key words] experiment design, contrast experiment, contrast experiment.In the biology curriculum of new senior high school, the experimental design is much better than before, while contrast experiment and contrast experiment are two important aspects of experiment design. Therefore, the new curriculum emphasizes on it and requires students to really understand and apply the differences and connections between the two experimental designs. The comparison between old and new high school biology curriculum can be found, the new curriculum in the background of quality education, advocate to find problems on the concept, so as to improve the students' ability of scientific research, natural science and find out the problems and to explore the necessary to design experiments to solve. Here is an example to talk about two important experimental design methods -- control experiment and contrast experiment, in order to helpstudents understand and apply biological experiment design.1. Control experiments1.1 control group: control experiment, two groups of experiments, one blank experimental group or normal experimental group or the experimental group known as the control group.1.2.1 example[experimental] experimental topic: design experiments prove that an insect respiratory effects produce CO2.Experimental procedure:A: take the same kind of live insects and divide them into two groups.After B and the killing of group B insects, two groups of insects were placed in airtight devices, all communicated with clarified lime water. The other conditions were the same and suitable. After a period of time, the two groups of lime water were observed.Results: the first clear limewater turbid, group B clarify lime had no change.Experimental results: an insect can produce CO2 by respiration.Analysis: in the above experiments, because the group B insectswere equal dead insects, which were equal to the experimental materials, the experimental group was the blank group, and the control group. We don't think it is not a blank control group to the control group in any processing factors, treatment factors just don't add variables in the experimental group, blank control group actually still need some treatment, such as blank control group group B in the above experiment is made to kill insects processing.[experimental group] experimental topic: design experiments prove that thyroid hormone can improve the excitability of animal nervous system.Experimental procedure: A: take two normal rats of equal size, number two, B and B.B: the first feeding amount and add a certain amount of thyroid hormone, normal diet group was fed with B, other conditions (temperature, humidity, brightness, etc.) are the same and appropriate, after a period of time, to compare nerve excitability in two groups of mice.Results: the group of mice compared with group B mice is jumping up and down, it is difficult to calm......Conclusion: thyroid hormone can improve the excitability of animal nervous system.Analysis: the above experiment, the group B rats not fed thyroid hormone, but also know everything before the experiment the rats of normal physiology, including nerve excitability, thenormal experimental group, control group control experiment.[experimental results] experimental topic: design experiments to verify that thyroid gland can affect the development of young animals.Experimental procedure: A: take two rats of the same kind and size;B: a thyroid gland was removed, B was not removed, other living conditions were the same and suitable for a period of time. The development of the two young rats was compared.Results: the first stop in growth, while group B rats in normal growth and development.Conclusion: thyroid gland gland can affect (promote) the development of young animals.Analysis: in the above experiments, because the young rats did not remove the thyroid gland, which itself is a normal development, known as the experimental results of the experimental group, so as the control of the experimental group.Here it is worth more than normal: the experimental group (without thyroid hormone) and the known experimental results in the experimental group (without resection of the thyroid gland), experimental verification is understood as independent variables per capita as the blank control, is justified.1.3 experimental group: Based on the control group to do an experiment, and draw a scientific conclusion, generally unknown experimental results of the experimental group, in general, is artificially processed the independent variables of the experimental group.1.3.1 for example, in the example above (1.2.1) in group A were put live insects, resection of the thyroid and thyroid hormone fed feed, were the experimental group treated with artificial variables, as the experimental group, no longer.2 、 contrast experiment2.1 definition: set up two or more than two experimental groups, by comparing the results to explore, explore the relationship between a certain factor and the experimental object, generally applicable to inquiry experiments.2.2 understand: a comparative experiment is refers to the comparison between experimental results, is a parallel relationship between experimental groups, no significant difference between control group and experimental group between group and group, if the specified one as the experimental group, the other group was the control group at the same time, the group can also be the control group group, the contrast experiment and the category than the control experiment, because the contrast between the two groups in each experiment any is actually a control experiment, because between the two groups is a different factors (independent variables). Therefore, some people call the contrast experiment a reciprocal contrast experiment.2.3 examples: experimental topic: design experiments to explore the appropriate concentration of willow cuttings rooting solution.Experimental procedure: A prepared the mass percent content of 0.1%, 0.2%, 0.3%, 0.4%, 0.5% concentration of auxin dilution solution.B, soaking the same length and thick willow roots for three times in each long life dilution solution, and observing the rooting status of each willow branch for a period of time.The results showed that the average number of rooting was the highest in the 0.2% groups.Conclusion: 0.2% auxin solution can promote the rooting of willow cuttings.2.4 analysis: in 0.2% of the auxin solution, willow cuttings rooting most, but if there is no other group of control, we can not say that 0.2% of auxin solution is above the concentration of auxin solution in the most appropriate concentration. Of course, without 0.2% of auxin solution as a control, we can not say that other auxin solutions are not the best concentration, so the parallel relationship between the experimental groups in the comparative experiment is parallel. It is worth noting here is a concentration gradient, pH gradient, temperature gradient in the experiment design, the appropriate gradient range to determine the precise design of the smaller gradient, such as auxin solution presented above 0.2% could promoterooting of switchgrass, we can in a concentration of 0.2% or less concentration gradient design to measure, such as 0.18%, 0.19%, 0.20%, 0.21%, 0.22%...... There is no best, only better. In addition, compared with the gradient experiment design in the experiment, we should design more than three groups at least.Finally, it is also clear that not all experimental designs need to be designed as a control group, and some factorial experiments do not require the control group, such as Mendel's genetic law, and the experiment does not require a control group.To sum up, we know that the experiment design is important and difficult knowledge of traditional biology teaching in senior high school, a kind of questions in recent years in the college entrance examination is compulsory, so students still need to understand the difference and connection between the experimental and control experiments. It is helpful to improve the ability of experiment design by means of example analysis, comparison experiment and contrast experiment.ReferenceBiology (ordinary high school curriculum standards, experimental textbooks, compulsory 1), people's education press, Zhu Zhengwei, Zhao Zhanliang editor in chief.Interpretation of experimental design principles in the new biology curriculum of senior high schoolWang Qiong (Feidong No.1 middle school, Anhui 231600)[Abstract] combining the subject characteristics of the new curriculum of biology in senior high school, this paper interprets the six principles that should be followed in the experiment design by means of concepts and examples. Accurate grasp of the principles of experimental design is the premise of the conclusion of scientific experiments.Interpretation of the principles of experimental designA new round of basic education curriculum reform has a profound impact on Teachers' thinking patterns and educational ideas. Biological science, as a natural science, speaks with natural facts. It always advocates inquiry learning, especially the new curriculum standard, which pays more attention to the development of students' scientific inquiry ability. Through the experimental design to cultivate students' scientific inquiry ability, comprehensive practical ability, knowledge application ability and innovation ability, is a very good means. The following is the author through the teaching practice of experimental design required to follow the six principles of interpretation.1, the control principleIn the experiment design, usually set in the control group, the intervention or control subjects to eliminate or reduce the error in the experiment of differential treatment factors (independent variables) with non treatment factors (independent variables) difference. Many control methods canbe used in the experimental design, in addition to the standard control, self control and mutual control, usually using control principle, which is called the control group any processing factors, it is worth emphasizing that, without any treatment to the control group, the experimental group and the other factor is relative, in fact the control group still need to do some the processing, processing factors only without the experimental group.The principle of comparison is the first consideration in experimental design, because there is no comparison, and the conclusion drawn from the single experiment is one-sided and can not explain any problem. For example, to verify that an oral preparation can be used to inhibit the growth of cancer cells, if only to some cancer mice oral preparation to observe the results, so that it is isolated results.Because people can think so: the preparation is to promote the growth of cancer cells, or inhibit the growth of cancer cells, or the growth of cancer cells have no stimulative effect, nor inhibition. If there is another group of the same cancer mice oral preparation (oral saline), at the end of the two groups of mice appear different results were compared, the conclusion is convincing.2, the principle of single factor variablesThe principle of single factor variable, that is, control other factors unchanged, only change one of the factors (independent variables), observe its impact on the experimental results. In addition to the experimental factors to be dealt withthroughout the experiment, other experimental conditions are required to be consistent.The single variable principle is as important as the comparison principle, and it is the core principle that makes the experimental results convincing and must be observed. In order to follow the single factor principle accurately, we usually do the following design according to the following procedures.First of all, define the topic of experimental design. Some students in the reading material test questions often found in the process of teaching (not directly given experimental design, but the experimental design in information reading and chimeric to experimental materials), in the experimental subject did not find the case, just start writing up, which is equivalent to Tomb-sweeping Day grave worship. "The cemetery not found" (subject) and "cry", so that the results of the experiment are as can be imagined, remote from the subject.Secondly, in determining the subject of the experiment, we must find the theme of the experimental design in the subject, that is, the object that the experiment should explore or verify. If he did not find the theme, it is difficult to determine the independent variables, there is no way to follow the principle of the single factor variable, which is equal to theTomb-sweeping Day grave worship, to find a "graveyard", but did not find the "grave" (theme experimental subject) "cry", the experimental results obtained and the objective real results what is the.Finally, after defining the experimental topic, the principleof the single variable is followed by the principle of whether the subject (independent variable) has or not dealt with or not dealt with, which captures the backbone and lifeblood of the experimental design. For example: in order to verify whether insulin can reduce blood sugar, the problem here is clear, and the theme is the amount of insulin, insulin in the experimental group and the control group in the US is determined with and without the theme, but in reality, some students designed to do different insulin concentration gradient, so the conclusion suitable concentration of insulin is to reduce blood sugar. Instead of verifying that insulin lowers blood sugar levels, this is not the subject of the experiment. Here I would like to put forward some questions in the experiment is more than one theme, such as photosynthesis and chloroplast verification need light, two theme here are light and chloroplasts, should be dealt with separately these two themes, generally set up a group as the control group in the two experimental groups were set to no light and no theme the theme of chloroplast.3, the principle of portabilityThe principle of feasibility refers to the materials, equipment and practices needed for the experiment, so as to meet the objective facts. For example, verify the root to back of and stem growth is caused by gravity, this experiment is the subject of gravity, according to the theme of some students put in groups of two plants were placed in equivalent gravity environment, another group was placed in the weightless environment, only the single factor variable for this design is yes, but in the real life of a middle school students, how to put the plants in the zero gravity environment is difficultto achieve, if the hand is difficult to achieve in space, on the other hand, it is difficult to control space and other factors. So in the feasibility under the guidance of the principle, to another idea, to put each plant morphological changes where they in the same geographical conditions (horizontal, vertical display, display tilting display etc.), through the observation of the experimental results, the experimental results are accurate.4, random principleRandom variation principle in experimental design, refers to the study sample was randomly selected in the population, is the significance of this: one is that it can eliminate or reduce the system error, the test has universal significance significant; two is to balance the various conditions to avoid the deviation of the experimental results. The random principle in scientific research to some macro reflected in the obvious, such as the investigation of a certain period of time in a certain area of the male to female ratio, a survey of plants in grassland ecosystems and species quantity by sampling method.5, the principle of parallel repetition:The principle of equal repetition, that is, controlling the magnitude of a factor, repeating the experiment under the same conditions, and observing the extent to which it affects the results of the experiment.The principle of parallel repetition is understood in two ways.First, design experiments must be repeated; in other words, others can repeat the experiment, which is a sign of science.A review of the classical experiments in the history of biological science,Such as Hershey, Zeiss and other people's phage infection bacteria experiments, Mendel's exploration of the two major genetic laws, experiments, etc., are able to repeat later generations, and the feasibility of the principle is corresponding. The second is the stochastic principle, which requires random sampling of the sample, which can offset the bias caused by non processing factors to a considerable extent. But it can not eliminate all its influence, and the principle of parallel repetition is put forward to solve the problem. For example: validation of suitable growth hormone concentration can promote the development of individual young animal, in the experimental group and the control group in the number of all the tadpole is not random one or a few, but random dozens of above, this would eliminate one or two individual tadpole vulnerability experiment of large deviation caused by the accident factor.6, the principle of saving raw materialsSaving raw materials means that in the experimental design process, without affecting the conclusion of scientific experiments, we should try to save the experimental materials, and make sure that we live within our means".The principle of saving raw materials surface looks a bit inconsistent, and the parallel repetition principle in fact,such as above with tadpoles as the experimental material, we each can have only one or a few, but can not be used only for tens of thousands of, with spinal afferent nerve reflex arc in frog proof and spread the nerve function (the college entrance examination in 2003 the content, we can use) own control measures, the premise with normal reflex function in complete reflex arc, then cut off the afferent and efferent nerve to verify them on excitatory afferent and efferent function, the entire experiment with a frog, but does not need to according to the afferent and efferent nerve of the two independent variables to design two experimental groups respectively, plus a control group, with three frogs, however the frog is a protected animal, not abuse.The following six principles are followed in the experimental design, and they have a certain order in the experimental design. But there is no priority in following the dynamics. A scientific experiment design must follow these principles, and the relations between these principles are inseparable, complement each other, complement each other.Reference material：1, the "biological" (experimental high school curriculum standard textbook, compulsory compulsory 1, 2) people's education press, Zhu Zhengwei, Zhao Zhanliang.2, "high school biology teaching material whole solution", Tianjin people's publishing house, Wu Junmin editor in chiefModify time: Sun Apr 13 21:34:30 Greenwich standard time +08002014------。
![[实验微课3] 辨别“对比实验与对照实验” 2021版高考生物(山东)一轮复习](https://img.taocdn.com/s1/m/a7d327606294dd88d0d26b89.png)
