First, the background of principle materialization
One day, Percy, an electrician from Raytheon, USA? Spencer happened to find that the chocolate candy in his coat pocket melted when he was doing radar vibration experiment. Percy is a thinker. He didn't let the accident go. He was thinking, "Great, why does chocolate melt?" However, another time, just as he climbed the radar tower, the chocolate in his hand began to melt again. Looking around, there is no stove, only the radar is emitting powerful electromagnetic waves. He guessed that electromagnetic waves have the function of heating food. After a series of experimental studies, he confirmed this speculation and discovered the principle that microwave can make molecules in food move and generate heat. Thus, the world's first microwave oven was born in Percy's hands in 1947, and he realized the pioneering work of "cooking" food without fire.
From 1864, the British scientist Maxwell discovered electromagnetic waves to the invention of microwave ovens, it was only more than 80 years before and after, and people turned a physical principle into a practical technology, benefiting countless families. There are countless examples of concretization of this principle. Therefore, physical principles come from life, serve life, and more importantly, create life. The goal of physics teaching is to combine physics principles with innovative practice, encourage students to use physics knowledge and scientific principles flexibly, make inventions and technological innovations in combination with problems encountered in daily study and life, and continuously improve their innovative ability.
Principle materialization 1: Application of pressure principle ―― Constant liquid level ink bottle
As shown in figure 1, the ink level in the ink bottle in which the pen is dipped in water remains unchanged, so that the ink does not pollute the pen when the pen is dipped in water or absorbs water. It makes use of the pressure principle in physics knowledge: when the liquid level at the dip is lowered (lower than the air port) by using the pen to absorb water, air will enter the ink bottle, at this time, the pressure in the bottle will increase and the water pressure will come out until the pressure in the bottle is equal to the liquid level at the dip. At this time, the pressure in the bottle is the sum of the pressure generated by air entering the bottle and the pressure generated by the ink column (ink level difference), and the pressure at the liquid level of the dip nozzle is atmospheric pressure. In this cycle.
Second, the principle of materialization steps
Principle materialization is a creative practical activity that sets out from a certain scientific principle and solidifies the abstract principle into a creative and technical scheme of a new product or method through creative thinking design. First of all, the creator needs to use the scientific principles and knowledge he has learned to create a product or a new technology, which is the embodiment of innovative spirit; Secondly, in order to invent new products, creators need to learn and master many practical production techniques, and their hands-on ability will be strengthened; Thirdly, the creators have successfully transformed scientific principles into objects through creative thinking and hands-on production, which will greatly stimulate their interest in learning and creativity.
The creation mode of general principle materialization is shown in Figure 2.
1. Explore physical principles
Physical principles are all constructed by certain laws. Learning the principle of physics requires not only knowing what it is, but also knowing why it is. We must never be satisfied with memorizing the content. In other words, we should not only know the contents of physical laws, but also understand their backgrounds, and what physical phenomena are summarized through analysis; At the same time, we should pay attention to the exploration of physical principles and laws, especially experimental exploration. Try to do the experiment yourself, and the laws we find or get (even if they are repeated by others) are easier to understand.
2. Create a theme option
Guide students to look for inconvenient, inconvenient problems or unsatisfactory things in daily study, life and social activities with creative eyes, and then combine the physical knowledge and principles they have learned to make purposeful inventions or innovations.
Principle Materialization 2: Application of Siphon Principle ―― Never Leak Water Tank
(1) Life problem: The bottom of the sink is connected with a drainage device. Over time, due to the aging of parts and materials, gaps become larger and water seeps, which brings troubles to life.
(2) Physical principle: siphon principle
(3) Invention: Design a water tank with no water outlet at the bottom, and then use a siphon to discharge the water, as shown in Figure 3. Push the piston push rod down to the bottom, and water is forced into the drain pipe. According to the siphon principle, the water in the sink is automatically discharged until it is used up. Pull the piston push rod up to its original position for reuse. Because there is no water outlet at the bottom of the sink, the purpose of never leaking water is achieved.
3. Relevant information query
In order not to infringe others' intellectual property rights, we need to investigate our own creative goals, that is, market research, online inquiry and patent retrieval. If others have already made the same or similar products, then you can't continue to develop them, otherwise it will be a waste of effort and you won't get intellectual property rights.
4. Physical and chemical model design
According to the basic scientific principles, give full play to your intuition and creativity, and design the shape, structure, method and implementation plan of the topic. The design scheme is simple in materials, ingenious in structure and easy to realize, and it is a good design scheme.
Principle materialization 3: Application of Faraday electromagnetic induction principle ―― Battery-free remote controller
(1) Life problems: Remote controllers are widely used in household appliances, which leads to a large amount of battery consumption, followed by serious environmental pollution problems, so it is necessary to invent a remote controller without batteries.
(2) Physical principle: Faraday electromagnetic induction principle.
(3) Information inquiry: ① After patent inquiry, the self-generating flashlight already exists, but the battery-free remote controller has not, so the project can be developed; ② We can refer to the principle of self-generating flashlight when developing, which conforms to the technology of invention-transplanting invention. Or, directly based on the principle of electromagnetic induction.
5. Other skills assistance
Logic means that writing articles or doing things can be done in order, and so can invention and creation. In the process of creation, all scientific principles, methods, skills, experiences and technologies are "principles". Only by arming these "principles" can you gallop on the battlefield of "creation" and reach the other side of success. Therefore, in addition to teaching students physical knowledge and principles, we should also infiltrate some creative methods and skills, and even train some practical production techniques, such as combinatorial invention and machining technology. Only in this way can it be possible to turn virtuality into reality and intangible physical principles into tangible inventions.
6. Inventions and achievements
According to the pre-designed scheme, make a model to test and see if the design scheme is effective. Then, constantly revise and improve until the work is completed.
Principle materialization 4: Application of buoyancy principle ―― faucet water stop and opening protector
(1) Creative theme: Sometimes you forget to turn off the tap when water is stopped. Sudden water will easily lead to water overflow, which will not only waste water resources, but also cause losses such as water leakage. Make a device that can close the waterway when water comes.
(2) Information inquiry: "Alarm of tap water not turned on" already exists, and no other report has been found.
(3) Physical principle: the definition of buoyancy-the pressure difference between the upper and lower surfaces of an object in fluid (including liquid and gas). Many teachers have done an important experiment when verifying this principle-buoyancy disappears, as shown in Figure 4.
Equipment: a glass funnel of suitable size, a ping-pong ball and a glass of red water.
Steps: ① Push the ping-pong ball into the water intentionally, and it will float quickly after being released. (2) Hold the funnel with your hand, put the ping-pong ball in, hold the ping-pong ball with your thumb, pour water into the funnel, and loosen your thumb, and you can see that the ping-pong ball does not float. At this time, there is water flowing out from the lower mouth of the funnel handle, which is because the ping-pong ball is not tightly connected with the funnel. Block the water outlet with your fingers, and you can see that the water level in the handle of the funnel rises gradually. When the water level rises to table tennis, table tennis immediately floats.
(4) Physical and chemical design and experiment: Inspired by the experiment of "buoyancy disappearing", a student invented the "faucet protector", and its structural principle is shown in Figure 5.
Material: PVC pipe as the main body, with self-defined size; Floating balls should be hollow balls made of rubber.
Verification: ① Place the floating ball from the ball placement opening; (2) respectively connecting the water inlet pipe of the protector with the tap water pipeline, and connecting the water outlet pipe with the faucet; (3) Close the tap water inlet valve and open the faucet to let the water flow out; (4) Open the tap water inlet valve, and the faucet will flow out without water, indicating that the floating ball sinks and blocks the water outlet; ⑤ Wait for a while after turning off the tap. According to the principle of buoyancy, the floating ball should float, and then turn on the tap, and water should flow out, but no water will come out. The experiment failed. Why?
Exploration: ① The water does not flow out, indicating that the floating ball does not float, that is, the floating ball has no buoyancy. What is the reason? (2) Actually, the step (4) of verification has predicted the problem. Because there is no gap between the floating ball and the smooth pipe wall and no water flows out, there will always be no water under the floating ball (even if the faucet is turned off), so it is not surprising that the floating ball can't get buoyancy and can't float. (3) roughening the pipe wall between the floating ball and the water outlet to make a small amount of water leak from the water outlet. ④ Repeat the verification again, and it was successful.
(5) Creating achievements: ① Selecting suitable materials and certain sizes to make finished products; ② The protector has a defect, that is, the floating ball can never completely close the water outlet, and a small amount of water must be released, which will also cause a small amount of water to be wasted. Therefore, follow-up research is needed to improve the creative achievements.
To sum up, physics teaching should not only improve students' scientific literacy, but also let students learn to innovate, be brave in creating and constantly enhance their skills. Principle materialization is a very effective means.
(Editor Guo)
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