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1、 Biological experiments on the test problems can easily ariseIn recent years, although the theoretical knowledge on the test organisms, but biological experimental operation has been compulsory in the examination content. Thus, the biological experiments in junior high school biology plays an import
2、ant role in the experimental years of junior high remedial teaching practice, I address students in the biological experiments operating problems can easily arise in a few personal views. First, experimental purposes, and equipment use is not clear Despite a third-year students, but they rarely have
3、 the opportunity to do experiments. For this reason, although the first day and two days when they have learned theoretical knowledge, but the specific operation is still quite strange experiment. Team bench side of the apparatus, they are not afraid to get involved, is poking at a stretch while we
4、are focusing on what experiment, the test questions in the test experiment of all living things are placed together, the experimental stage of the instrument is quite more, and specific to each instrument used in an experiment is not the same, which requires students to experiment, to be clear inten
5、t of the experiment and the equipment, otherwise the purpose is not clear, the role of experimental apparatus is unclear, wrong in the experiment do not know. Sometimes, though experiments to be completed, but the experimental results, test quality is not good. For example, the experimental observat
6、ion of the structure of kidney bean seeds, the main purpose is to recognize the structure of bean seeds. Use to dip with a soft bean seeds, single blade, tweezers, petri dishes, anatomy, such as acupuncture. One of the single blade can be used to draw on the seed coat a small opening can not, take t
7、he forceps can be used to clip the seed or the stripped seed coat, embryo dissection needle is used to indicate various parts of the structure. Some students pick up the blade on one side indiscriminately together, cut beans, tomatoes, onions, and then dissected in a petri dish with a mix needle or
8、tweezers, toothpick wearing you can eat, humorous, a few students do so. Most of the students are holding a single bean seeds go cut the blade surface, place the single-sided blade do not know beans, seeds can be used to draw the seed coat. Thus, the clear intent of the experiment before the experim
9、ent and the equipment use is very important. Second, the experimental procedure is not standardized Experimental operational capability of students, the first requires students to proficiency, standardized experiment to master the instruments and tools used in the experiment pre-school teachers to p
10、repare, what to do personally under the experimental content and master the whole process of experiment, the experimental the whole process to make reasonable arrangements. For example, in experiments using a microscope, requiring teachers to demonstrate strict compliance with procedures. To pick up
11、 the mirror and placed it, while I preach : Hold the mirror hand mirror hand holding the seat arm, while operating a demonstration students to experiment along with the author. This is easy to develop students ability to regulate the experimental operation the same time added, are interchangeable le
12、ft and right, but not with one hand take a mirror, so tilt the microscope eyepiece to prevent the fall. Light should be careful not to pull with a high power objective lens or light, observation should adhere to the eyepiece with an inside look at the other eye open and so on. Drop tube must be stre
13、ssed that when the eyes look from the side of the lens, to prevent the slide to be crushed, pressed film clip to hold the two ends of the slide, slide in the observation process to prevent falls. Then let the students under the guidance of teachers to complete the experiment in strict accordance wit
14、h standard operation, the accumulation of such a meeting, the students will gradually operating capacity. Third, the observation with blindness Biology of each experiment, has a clear purpose of the request, the purpose of the request should be clear to the students, to reduce the blindness of the e
15、xperiment to ensure that students focus on the observed object. Links to free download :/eng.hi138 example, observe the temporary installation of films, some of the students to focus on playing with a microscope to observe the wandering of the bubble, while ignoring the key observation target. Again
16、 students of low magnification and high magnification of choice, often not based on the observed characteristics of the object and purpose of observing a reasonable choice to use. Students often because of curiosity and low magnification, high-power characteristics of ignorance, is always one up on
17、the use of high-power, low-fold better than that high-power microscope clearly. This blindness is the result of the students do not understand the microscope The basic principle, do not understand the high-power magnification of large, high resolution, but see the actual size, that is, small field o
18、f view, and the higher the multiple, the more to see the thickness of the material is thin, high-power microscope suitable for observation of local and details In some experiments, some illusion, the non-observation of the object as object of observation, which will affect the observed results. Teac
19、hers should guide students to avoid such interference, see the need to observe things, for example, using a microscope in a number of experiments required , the first experiment the students will tend to dirt on the microscope, fitted sheet on the bubble as the object of observation, this is the ill
20、usion of interference, should be promptly corrected. Fourth, the experiment used to easily commit errors After several experiments, the students are no longer committed an error in principle, but the total can not be used to avoid errors, for example, use mounts in the experiment, get loaded film is
21、 easy to commit habitual errors, get loaded films should take the mounts on both sides, and not take sides, from the first experiment has been stressed that the method to get fitted sheet, and in a long period of time, many students will make that mistake and they get that piece installed Hand and m
22、ounts on both sides of the contact area, it is not easy to fall off. then the teacher must give students clear, hand fitted sheet fitted on both sides are likely to encounter on-chip samples, or wear the label on the chip installed, students understand this truth, the general can do both sides are n
23、o longer fitted sheet to take. Clean glass slide in when a student habitually rub back and forth this time, students can give an example of life, Cabo desktop, rub in one direction than the rubbing back and forth to clean the student will be able to remember what. Cut maize seeds and tomato, the stu
24、dents habitually cut on the desktop, only one questioning the teacher will be able to solve the problem, the cooking at home, you can cut directly on the table it? students picked up a small wooden smile In experiments using a microscope, a third-year students were generally larger effort, habitually put a hand over a microscope to get the teacher made it clear that the purpose is to prevent unexpected microscope tilt so the saying goes habits into a natural