Experimental demonstration is the best way to stimulate students to learn physics. However, due to various conditions, the laboratory cannot provide all experimental teaching AIDS. In this case, we have to make our own teaching AIDS to explore the mysteries of science. Although the self-made teaching AIDS are not so sophisticated, they also add a lot of elegance to the physics class.
Keywords: physics experiment with self-made teaching AIDS
Because of the particularity of physics, experiment is an indispensable part of it. My long-term experience in front-line work tells me that it is very important to do experiments well in physics teaching, which can also be said to be the best way to make students interested in physics. The course of physics is to study the laws of objects. Explain "reason" clearly. The traditional teaching method of "one powder" and "reason" is no longer applicable in the new era. Chairman Mao once said, "If you want to know the taste of pears, you have to eat them yourself." The same is true when we study physics. If you want to know that "principle", you must do experiments yourself and get the truth from practice. However, due to various conditions, the laboratories of various schools, especially rural schools, cannot provide all experimental teaching AIDS. We must continue our physics class. What should we do? At this point, self-made teaching AIDS can solve these problems.
First, self-made teaching AIDS can make up for the shortage of experimental teaching AIDS.
"If we don't have guns, we will build them ourselves", and actively respond to the slogan of "Do it yourself and have plenty of food and clothing" put forward by Comrade Chairman Mao. Physics studies the "principles" around us, so we should be able to use common objects around us to make our own teaching AIDS for inquiry experiments. It can be used to fill the shortage of experimental teaching AIDS, especially in rural schools. Due to the pressure of funds, some expensive experimental instrument schools simply can't afford or don't have enough funds to maintain the existing teaching AIDS, which leads to serious shortage or damage of experimental teaching AIDS. So there is no way to carry out many experiments close to teaching AIDS in the laboratory. For example, what we are studying now is the slightly changed knowledge points in the section "Elasticity". Students all know that when we squeeze sponges, stranded wires and other objects, there are obvious deformations, and students can directly observe them with their eyes. Everyone understands this. Now, you said that when we squeeze the desktop or the wall with our fingers, the desktop and the wall are also deformed. At this time, our students squeezed the desktop or wall with their hands and didn't see the desktop or wall deformed. As the saying goes, "Seeing is believing, but listening is empty", then students can't accept this "reason". If they accept it, they can only force their memory. However, our problem now is that there is no experimental teaching aid to observe the change of smile in the laboratory. In order to solve this problem, we can only make our own teaching AIDS. We can finish this experiment with a glass bottle with a big belly and a narrow mouth. The specific method is as follows: prepare a glass bottle, a slender glass tube, a rubber stopper, some water mixed with red ink and wax blocks, insert the glass tube into the rubber stopper, fill the glass tube with water mixed with red ink, then plug the glass tube with the rubber stopper, and finally seal the leaking part of the bottle mouth with wax. In this way, a simple self-made experimental teaching aid for studying micro-deformation is ready. When we squeeze the glass bottle by hand, we will find that the red ink in the glass tube will rise, and the water will fall when we release our hands. Whether the water level in the glass tube rises or falls, it is caused by the tiny deformation of the glass tube after being squeezed. Making several common daily necessities into experimental teaching AIDS has the advantages of low cost, simple operation and obvious phenomenon, and it has advantages over excellent factory-made teaching AIDS in some aspects.
Second, self-made teaching AIDS can improve the shortcomings of existing experimental teaching AIDS.
Although the experimental teaching AIDS made by the factory are excellent, the experimental teaching AIDS made by the factory sometimes feel that they are not enough because of the updating of courses or the aging of teaching AIDS. For example, when we study that no matter whether an object is light or heavy, it has the same acceleration of gravity, we will use Newton tube to demonstrate it to students. Theoretically, when there is air in Newton's pipe, the feathers and iron pieces inside will not fall to the bottom of the pipe at the same time because of air resistance; When the air in Newton's tube is evacuated, both of them fall to the bottom of the tube at the same time. But when we did the experiment, we found that the effect was not obvious whether there was air in the pipe or not. It seems that two people fell to the bottom of the pipe at the same time. It turns out that the feather inside is the root of hair, which is much harder and heavier than we thought. Moreover, the air extractor equipped with Newton tube is also a big trouble. This is a heavy guy and inconvenient to use. For such an experimental teaching aid, I think many teachers are reluctant to use it in class. Actually, we want to finish this experiment. All we need is a piece of paper and a chalk head. At the beginning, when the paper is unfolded and the chalk head is released at the same position, we will find that the chalk head touches the ground first. If we knead the paper into a ball or put it in the same position as the chalk head, we will find that both fall to the ground at the same time, which also plays the role of "Newton tube" It can be seen that this self-made teaching aid is much better than Newton's tube.
When junior high school physics explores the "buoyancy essence" problem, it is usually explored through the demonstration instrument of the relationship between pressure and depth and theoretical analysis: students can only know that the object in the liquid has pressure through the demonstration instrument of the relationship between pressure and depth, and it changes with the change of depth, and then we analyze the forces on the upper, lower, left and right surfaces of the object, and analyze that the essence of buoyancy is caused by the pressure difference between the upper and lower surfaces of the object. This kind of inquiry is acceptable to students, but students may not be deeply impressed. In order to leave a deeper impression on students, we can improve the shortcomings of this experimental teaching aid by making our own experimental teaching aid.
(1) prepared utensils: a large glass water tank with an open top, a small glass box sealed around, a rubber tube, a plastic beverage bottle stopper, wax block and super glue;
(2) Instrument installation: As shown in the figure, small holes with appropriate size are opened on the left and right sides of the sealed small glass box, and the rubber tube is bonded with the small hole on the right side with super glue to ensure water leakage; Then, a hole slightly smaller than the plastic bottle stopper is opened above the glass box, a layer of wax block is coated around the hole edge, and it is ground flat, and the plane of the bottle stopper is pressed down on the hole.
(3) Experimental content: Inject a proper amount of water into the large glass water tank, and press the left hole of the small glass tank with your fingers, so that the water will not enter the tank from the left hole when the small glass tank is filled with water; Put the small glass box into the water smoothly and gently until the bottle cap is at a distance from the water surface, and one end of the rubber tube leads to the outside of the large glass box. At this time, you will see that the plastic bottle cap is not floating in the water. Slowly release the finger pressing the left hole, and water will enter the glass box from the hole. When the small glass box is filled with water, the plastic bottle cap will float.
(4) Experimental principle: In this experiment, the rubber tube is connected with the outside world, the atmospheric pressure inside and outside the small glass box is the same, and the pressure on the lower surface of the plastic bottle cap is the same as the outside world. When the plastic bottle cap sinks into the water, it will also be under the downward pressure of the water. At this time, the pressure at the top of the bottle cap is greater than that at the bottom, and the plastic bottle cap will not float. When the hole on the left side of the small glass box is loosened, the glass box is filled with water, and the water contacts with the lower surface of the bottle cap. At this time, the pressure of water on the lower surface of the bottle cap is greater than that on the upper surface, and the bottle cap floats under the action of the pressure difference between the upper and lower surfaces, indicating that buoyancy is caused by the pressure difference between the upper and lower surfaces.
(5) The advantages of this experiment are: (1) During the whole experiment, the pressure on the bottle cap has a changing process: when the bottle cap is in the water, it cannot float due to the downward pressure of the water; When the air in the glass box is emptied, under the pressure of water, the surface of the bottle cap is larger than the upper surface, and the bottle cap floats; (2) The experimental process is a dynamic process. Compared with static experiments, dynamic experiments can arouse students' interest and stimulate them to think. (3) Although this experimental teaching aid looks very complicated, in fact, it only needs tens of dollars to make this experimental teaching aid, and the glass shop can do it, which is very cost-saving.
Third, self-made teaching AIDS can cultivate students' innovative spirit.
The production of experimental teaching AIDS can also be completed by students. As the saying goes, "Two heads are better than one", and students' thinking should not be underestimated. Students with the same knowledge point can exert their intelligence and make different experimental teaching AIDS. Classes can regularly carry out appraisal activities and reward students with practical and innovative teaching AIDS, which not only cultivates students' innovative spirit, but also stimulates students' interest in learning physics. Self-made experimental teaching AIDS are not a simple process. Students should first understand the principle of the experiment, then choose the props of self-made teaching AIDS from their side, and then design, make and innovate. The same material, through different designs, can be made into a variety of experimental teaching AIDS, such as common plastic bottles around us, which can be seen everywhere. What's the use? It's actually very useful. After processing, it can be made into experimental teaching AIDS involving mechanics, optics, heat, electricity and other knowledge: (1) Exploring the friction experiment, holding a plastic bottle in your hand, the bottle did not fall, indicating that it was subjected to vertical static friction; (2) An experimental teaching aid to experience the existence of atmospheric pressure. A plastic bottle is filled with water, pressed tightly on the bottle mouth with a piece of cardboard, and then the bottle mouth is facing down. It is found that cardboard can hold water, which strongly proves the existence of atmospheric pressure. (3) Experimental teaching AIDS for experiencing light refraction. Through the plastic bottle filled with water, you can find that the object has become bigger and you can experience the phenomenon of light refraction. (4) Experience the phenomenon of friction electrification. Rub a small plastic bottle with silk or Mao Mao skin and put it near the paper. You will find that the paper is attracted, which is caused by the charged plastic bottle attracting light and small objects. A common and possibly inconspicuous object in life can actually be made into a teaching aid for physics experiments. The key is to see if there is a sense of innovation. Adhere to the habit of cultivating students' self-made teaching AIDS, and students' physical thinking will become wider and wider; In fact, if teachers insist on trying to make their own teaching AIDS, their comprehensive professional level will be greatly improved.
In short, insisting on self-made teaching AIDS will play a positive role in our physics teaching quality, teaching reform and the improvement of teachers' professional level.
References:
[1] Chen. Developing self-made teaching AIDS to solve experimental teaching problems. Teaching Instruments and Experiments, 2007( 12).
[2] Lu Dongmei. Ge yongwen Making physics teaching aids in middle schools. Middle school physics teaching reference 200 1, (09).
[3] Liu Youju. Self-made teaching aids in middle school physics teaching. Journal of Baoshan Teachers College, 2000, (04)
[4] Bao Liang. Design and manufacture of physics teaching aids in middle schools. New Curriculum Learning (Social Synthesis) 2009, (03).