Bernoulli principle visual demonstration teaching aid

Abstract

The utility model discloses a Bernoulli principle visualization demonstration teaching aid, comprising an air supply assembly having an air outlet, the air speed at the air outlet of the air supply assembly being adjustable; the bending sensor is arranged on one side, in the first direction, of the air supply assembly and is arranged on the downstream of the air outlet in the airflow direction, the first direction is perpendicular to the airflow direction, and the bending sensor bends towards the side close to the air supply assembly under the action of the airflow; and the acquisition module is connected with the bending sensor and is used for acquiring the resistance of the bending sensor, the Bernoulli principle visual demonstration teaching aid provides airflow with different flow speeds through the air supply assembly, and the Bernoulli principle visual demonstration is realized by using different resistance values of the bending sensor under different bending conditions.

Description

TECHNICAL FIELD

[0001] The utility model relates to a teaching aid for physical demonstration, in particular to a Bernoulli principle visualized demonstration teaching aid. BACKGROUND

[0002] Bernoulli principle points out that in fluid flow, fluid velocity increases will result in fluid pressure drop, on the contrary, when the flow slows down, the pressure will increase, the pressure difference on both sides of the object will produce force, resulting in object movement or deformation.

[0003] Bernoulli principle is one of the main contents in physical teaching, in the process of physical teaching, because Bernoulli principle is relatively complex, when the teacher explains Bernoulli principle, using traditional teaching method, students are not easy to understand, traditional experimental device can only observe object movement or deformation to observe the force generated under Bernoulli principle on the goods, cannot directly observe the force change caused by the difference of flow velocity on both sides of the object. UTILITY MODEL CONTENT

[0004] The utility model aims at at least solving one of the technical problems existing in the prior art, for this purpose, the utility model provides a Bernoulli principle visualized demonstration teaching aid, which realizes Bernoulli principle visualized demonstration and can directly observe the force change caused by the difference of flow velocity on both sides of the object.

[0005] To achieve the above object, according to the embodiment of the utility model provides a Bernoulli principle visualized demonstration teaching aid, the Bernoulli principle visualized demonstration teaching aid includes: air supply assembly, air supply assembly has air outlet, the air speed of air supply assembly air outlet is adjustable;

[0006] Bending sensor, the bending sensor is arranged on one side in the first direction of air supply assembly and is arranged downstream of air outlet in the direction of airflow, the first direction is perpendicular to the direction of airflow, the bending sensor bends to the side close to air supply assembly under the action of airflow;

[0007] Acquisition module, the acquisition module is connected with the bending sensor, and is used for acquiring the resistance of the bending sensor.

[0008] According to the Bernoulli principle visualized demonstration teaching aid of the utility model embodiment, the air supply assembly provides airflow with different flow velocities, and the bending sensor realizes Bernoulli principle visualized demonstration by using different resistance values under different bending conditions.

[0009] In addition, the Bernoulli principle visualized demonstration teaching aid according to the above embodiment of the utility model can also have the following additional technical features:

[0010] According to one embodiment of the present application, the thickness direction of the bending sensor is perpendicular to the airflow direction.

[0011] And / or, the bending sensor bends to one side in the thickness direction, and at least one of the two side surfaces in the thickness direction of the bending sensor is provided with a direction mark.

[0012] And / or, the projection of the bending sensor in the plane of the air outlet in the unstressed state is located at the edge of the air outlet or outside the air outlet.

[0013] According to one embodiment of the present application, the axial distance between the bending sensor and the air outlet is less than 15 cm.

[0014] And / or, the radial distance between the bending sensor and the air outlet is less than 8 cm.

[0015] According to one embodiment of the present application, the air outlet is a circular air outlet, and the diameter of the air outlet is less than half the length of the bending sensor.

[0016] According to one embodiment of the present application, the air supply assembly comprises a shell and a fan, the shell defines an air duct, and the air outlet is formed in the first direction of the shell and communicates with the air duct, and the fan is arranged in the air duct.

[0017] And / or, the maximum air speed at the air outlet is not less than 4 m / s.

[0018] According to one embodiment of the present application, the Bernoulli principle visual demonstration teaching aid further comprises a control module and an alarm device, the control module communicates with the acquisition module and the alarm device, and controls the alarm device to alarm when the resistance value acquired by the acquisition module is lower than the preset value.

[0019] According to one embodiment of the present application, the acquisition module comprises a resistance measuring instrument.

[0020] According to one embodiment of the present application, the acquisition module further comprises a control circuit, the control circuit comprises a power supply circuit, a detection circuit and an alarm circuit, the power supply circuit is used to provide power, the alarm circuit is connected with the alarm device, and the power supply circuit and the alarm circuit are respectively electrically connected with the detection circuit; the detection circuit comprises the bending sensor, and the detection circuit is adapted to connect the power supply circuit and the alarm circuit when the bending sensor is bent.

[0021] According to one embodiment of the utility model, the Bernoulli principle visual demonstration teaching aid further includes a fixing support, the air supply assembly is fixedly arranged on the fixing support through a first fixing part, and the bending sensor is fixedly arranged on the fixing support through a second fixing part.

[0022] According to one embodiment of the utility model, the first fixing part includes a bandage, and / or the second fixing part includes a fixing clamp, and / or the air supply assembly includes a blower.

[0023] The additional aspects and advantages of the utility model will be partially given in the following description, some will become obvious from the following description, or be known through the practice of the utility model. BRIEF DESCRIPTION OF DRAWINGS

[0024] The above and / or additional aspects and advantages of the utility model will become apparent and more readily appreciated from the following description of the embodiments, with reference to the following drawings, in which:

[0025] Figure 1 is the structure schematic view of Bernoulli principle visual demonstration teaching aid according to the utility model embodiment;

[0026] Figure 2 is the local structure schematic view of Bernoulli principle visual demonstration teaching aid according to the utility model embodiment.

[0027] Reference Signs:

[0028] Demonstration teaching aid 100, air supply assembly 101, blower 102, shell 11, air outlet 111, bending sensor 2, fixing support 3, acquisition module 4, bandage 5, fixing clamp 6, alarm device 7, power supply 8. DETAILED DESCRIPTION

[0029] The present application is made based on the discovery and understanding of the inventor on the following facts and problems:

[0030] Bernoulli principle points out that in fluid flow, fluid velocity increases will result in fluid pressure drop, and vice versa, when the flow rate slows down, the pressure will increase, and the pressure difference on both sides of the object will produce force, causing the object to move or deform.

[0031] Bernoulli principle is one of the main contents in physics teaching, in the process of physics teaching, because Bernoulli principle is relatively complex, when the teacher explains Bernoulli principle, the traditional teaching method is used, students are not easy to understand, the traditional experimental device can only observe the movement or deformation of the object to observe the force acting on the object under Bernoulli principle, and the change of the force acting on the object caused by the difference of flow rate on both sides cannot be observed directly.

[0032] To this end, the utility model discloses an embodiment designs a kind of through bending sensor 2 realizes Bernoulli principle visual demonstration teaching aid 100, when the fluid flow rate of bending sensor 2 thickness direction two sides is different, different pressure difference will produce force to drive bending sensor 2 stress deformation, when the fluid flow rate of bending sensor 2 thickness direction two sides is different, the force that bending sensor 2 is different, bending degree is different, bending sensor 2 with different properties of different bending degree, specifically, bending sensor 2 bends to different degree with different resistance value, whereby, by changing the fluid flow rate of at least one side of bending sensor 2 thickness direction, observe the bending shape change and resistance value change of bending sensor 2 under different flow rate, i.e. the fluid flow rate difference of thickness direction two sides under different flow rate, that is, the force change that two sides different flow rate difference leads to under the action of Bernoulli principle can be directly observed, realizes Bernoulli principle visual demonstration.

[0033] The embodiments of the utility model are described in detail below, and the examples of the embodiments are shown in the drawings, wherein the same or similar reference signs represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary, only for explaining the utility model, and cannot be understood as limiting the utility model.

[0034] In the description of the utility model, it needs to be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" are based on the orientation or positional relationship shown in the drawings, only for the convenience of describing the utility model and simplifying the description, and cannot be understood as indicating or implying that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, therefore, cannot be understood as limiting the utility model. In addition, the features limited as "first", "second" can be explicitly or implicitly include one or more features. In the description of the utility model, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0035] In the description of the utility model, it needs to be explained that, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting" should be understood broadly, for example, can be fixed connection, or detachable connection, or integrally connected, can be directly connected, or indirectly connected through intermediate medium, can be the communication inside two elements. For ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood according to specific circumstances.

[0036] The following describes a Bernoulli principle visualization demonstration teaching aid 100 according to an embodiment of the present invention with reference to the accompanying drawings.

[0037] like Figures 1-2 As shown, the Bernoulli principle visualization demonstration teaching aid 100 according to an embodiment of the present invention includes: an air supply component 101, a bending sensor 2 and an acquisition module 4.

[0038] The air supply component 101 has an air outlet 111, and the wind speed at the air outlet 111 of the air supply component 101 is adjustable. The bending sensor 2 is arranged in the first direction (eg Figure 1 The bending sensor 2 is arranged on one side of the direction shown in A in the middle) and is located downstream of the air outlet 111 in the airflow direction. The first direction is perpendicular to the airflow direction. The bending sensor 2 bends toward the side close to the air supply component 101 under the action of the airflow.

[0039] The air supply component 101 can drive the airflow to change the fluid flow rate difference on both sides of the thickness direction of the bending sensor 2, wherein the thickness direction of the bending sensor 2 is the same as the first direction, and the bending sensor 2 is arranged on one side of the first direction of the air supply component 101, that is, the airflow generated by the air supply component 101 driving the air is located on the other side of the first direction of the bending sensor 2. Since the airflow on the other side of the first direction of the bending sensor 2 is driven by the air supply component 101, the flow speed is faster. The Bernoulli principle points out that an increase in fluid velocity will cause a decrease in fluid pressure. The pressure on one side of the first direction of the bending sensor 2 is high, and the pressure on the other side is low. The force generated by the pressure difference will drive the bending sensor 2 to bend toward the other side of the first direction.

[0040] The wind speed at the air outlet 111 of the air supply component 101 is adjustable, that is, the air supply component 101 can provide wind with different flow rates. By adjusting the wind speed at the air outlet 111 during the experiment, the fluid flow rate difference on both sides of the bending sensor 2 in the thickness direction is different in different experimental stages. Different flow rate differences lead to different forces and different bending degrees on the bending sensor 2 in different experimental stages. The bending sensors 2 with different bending degrees have different properties.

[0041] The bend sensor 2 has different resistance values ​​when bent to different degrees. The acquisition module 4 is connected to the bend sensor 2 and is used to obtain the resistance of the bend sensor 2. Therefore, by changing the fluid flow rate on at least one side of the bend sensor 2 in the thickness direction, the changes in the bending shape and resistance value of the bend sensor 2 under different flow rates, that is, different flow rate differences on both sides in the thickness direction, are observed. In this way, the changes in the force acting on the object caused by the different flow rates on both sides under the action of the Bernoulli principle can be intuitively observed, realizing a visual demonstration of the Bernoulli principle.

[0042] According to the Bernoulli principle visualization demonstration teaching aid 100 of the embodiment of the present invention, the Bernoulli principle visualization demonstration teaching aid 100 provides airflows with different flow rates through the air supply component 101, and realizes the visualization demonstration of the Bernoulli principle by using the different resistance values ​​of the bending sensor 2 under different bending conditions.

[0043] Among them, reference Figure 1 The thickness direction of the bending sensor 2 is perpendicular to the airflow direction, and the width and length directions of the bending sensor 2 are parallel to the airflow direction, so as to avoid the airflow directly driving the deformation of the bending sensor 2, and ensure that the bending deformation of the bending sensor 2 is caused by the different flow velocity differences on both sides of the thickness direction of the bending sensor 2, thereby ensuring the accuracy of the experiment.

[0044] Among them, the bending sensor 2 is suitable for bending to one side in the thickness direction. In order to ensure the accurate installation of the bending sensor 2, at least one of the two side surfaces in the thickness direction of the bending sensor 2 is provided with a direction mark, which can ensure that the bendable side faces the direction of the airflow during the experiment.

[0045] Furthermore, in order to avoid the influence of airflow on the demonstration of Bernoulli principle and to ensure that a significant flow velocity difference can be formed on both sides of the bending sensor 2 in the thickness direction, it is avoided that the bending sensor 2 is placed at the air outlet 111, which causes the airflow velocity on both sides of the thickness direction to be consistent. Figure 1 In the unstressed state, the projection of the bending sensor 2 on the plane where the air outlet 111 is located is located at the edge of the air outlet 111 or outside the air outlet 111. Therefore, when the air outlet 111 of the air supply component 101 supplies air outward, the wind can only flow through the other side of the bending sensor 2 in the first direction. The air flow velocity on one side of the bending sensor 2 in the first direction tends to be stationary, resulting in an obvious flow velocity difference.

[0046] Among them, the axial distance between the bending sensor 2 and the air outlet 111 is less than 15 cm, and the airflow blown out by the air supply component 101 through the air outlet 111 is dispersed after passing through the air outlet 111. The axial distance between the bending sensor 2 and the air outlet 111 is less than 15 cm, which can ensure that the airflow can be stably formed on one side of the bending sensor 2 in the thickness direction, and a flow velocity difference is formed on both sides of the bending sensor 2 in the thickness direction.

[0047] Furthermore, the radial distance between the bending sensor 2 and the air outlet 111 is less than 8 cm to avoid the bending sensor 2 being too far away from the air outlet 111, resulting in the airflow at the air outlet 111 being unable to drive the airflow on the other side of the bending sensor 2 in the first direction. The airflow velocities on both sides of the thickness direction of the bending sensor 2 cannot produce a flow rate difference, and then the bending sensor 2 cannot be used to demonstrate the Bernoulli principle.

[0048] like Figure 1As shown, the air outlet 111 is a circular air outlet 111, and the diameter of the air outlet 111 is less than half the length of the bending sensor 2. The tail end of the bending sensor 2 is fixed. In order to ensure that the bending sensor 2 can bend as much as possible, the force-bearing position of the bending sensor 2 during the bending process is as far away as possible from the fixed position of the bending sensor 2, which can make the bending angle of the bending sensor more obvious and facilitate observation.

[0049] The acquisition module 4 can be composed of different devices. The acquisition modules 4 composed of different devices can support the Bernoulli principle visualization demonstration teaching aid 100 to complete different experiments and achieve different experimental effects.

[0050] In some embodiments, reference Figure 1 , the acquisition module 4 includes a resistance measuring instrument. At this time, the Bernoulli principle visualization demonstration teaching aid 100 can complete the Bernoulli principle visualization demonstration through the following experimental steps.

[0051] First, secure the bend sensor 2 to one side of the air supply assembly 101 in the first direction and downstream of the airflow, with its thickness perpendicular to the airflow direction. To ensure accurate data, the bend sensor 2 should be positioned as close to the edge of the air outlet 111 as possible in the radial direction. The air supply assembly 101 should be turned on, and the airflow velocity at the air outlet 111 should be gradually increased. The resistance values ​​of the bend sensor 2 obtained by the resistance measuring instrument at different flow rates should be recorded.

[0052] Specifically, taking a bending sensor 2 with a length of 195 mm, a width of 8 mm, and a thickness of 0.4 mm as an example, in a horizontal state, the resistance value of the bending sensor 2 is 25 kilo-ohms, and the resistance difference error of the bending sensor 2 is within 20%.

[0053] When wind with a speed of 0 m / s-3.9 m / s is delivered to one side of the bending sensor 2 in the thickness direction through the air supply assembly 101, the bending degree of the bending sensor 2 is small, and the resistance value of the bending sensor 2 does not change much, and the resistance value of the bending sensor 2 is above 2000 ohms.

[0054] When the air supply component 101 delivers wind with a speed of more than 3.9 m / s on one side in the thickness direction of the bending sensor 2, the bending degree of the bending sensor 2 gradually increases, and the resistance value of the bending sensor 2 gradually decreases, and the resistance value of the bending sensor 2 is below 2000 ohms.

[0055] When the air supply assembly 101 supplies air at a speed of 4.09 m / s on one side in the thickness direction of the bending sensor 2, the bending degree of the bending sensor 2 becomes large, and the resistance value of the bending sensor 2 gradually becomes small, and the resistance value of the bending sensor 2 is between 700 ohms and 2000 ohms.

[0056] When the air supply assembly 101 supplies air at a speed of 4.6 m / s on one side in the thickness direction of the bending sensor 2, the bending degree of the bending sensor 2 becomes large, and the resistance value of the bending sensor 2 gradually becomes small, and the resistance value of the bending sensor 2 is between 500 ohms and 800 ohms.

[0057] When the air supply assembly 101 supplies air at a speed of 5 m / s on one side in the thickness direction of the bending sensor 2, the bending degree of the bending sensor 2 becomes large, and the resistance value of the bending sensor 2 gradually becomes small, and the resistance value of the bending sensor 2 is between 210 ohms and 250 ohms.

[0058] When the air supply assembly 101 supplies air at a speed of 5.1 m / s on one side in the thickness direction of the bending sensor 2, the bending degree of the bending sensor 2 becomes large, and the resistance value of the bending sensor 2 gradually becomes small, and the resistance value of the bending sensor 2 is between 170 ohms and 200 ohms.

[0059] When the air supply assembly 101 supplies air at a speed of 5.2 m / s on one side in the thickness direction of the bending sensor 2, the bending degree of the bending sensor 2 becomes large, and the resistance value of the bending sensor 2 gradually becomes small, and the resistance value of the bending sensor 2 is between 130 ohms and 140 ohms.

[0060] When the air supply assembly 101 supplies air at a speed of 5.5 m / s on one side in the thickness direction of the bending sensor 2, the bending degree of the bending sensor 2 becomes large, and the resistance value of the bending sensor 2 gradually becomes small, and the resistance value of the bending sensor 2 is between 125 ohms and 140 ohms.

[0061] When the air supply assembly 101 supplies air at a speed of 5.75 m / s on one side in the thickness direction of the bending sensor 2, the bending degree of the bending sensor 2 becomes large, and the resistance value of the bending sensor 2 gradually becomes small, and the resistance value of the bending sensor 2 is between 125 ohms and 130 ohms.

[0062] When the air supply assembly 101 supplies air at a speed of 6.2 m / s on one side in the thickness direction of the bending sensor 2, the bending degree of the bending sensor 2 becomes large, and the resistance value of the bending sensor 2 gradually becomes small, and the resistance value of the bending sensor 2 is between 120 ohms and 130 ohms.

[0063] When the air with a speed of 6.38 m / s is delivered by the air supply assembly 101 on one side of the bending sensor 2 in the thickness direction, the bending degree of the bending sensor 2 becomes larger, the resistance value of the bending sensor 2 gradually becomes smaller, and the resistance value of the bending sensor 2 is between 110 ohms and 120 ohms.

[0064] When the air with a speed of 6.74 m / s is delivered by the air supply assembly 101 on one side of the bending sensor 2 in the thickness direction, the bending degree of the bending sensor 2 becomes larger, the resistance value of the bending sensor 2 gradually becomes smaller, and the resistance value of the bending sensor 2 is between 100 ohms and 105 ohms.

[0065] When the air with a speed of 7.0 m / s is delivered by the air supply assembly 101 on one side of the bending sensor 2 in the thickness direction, the bending degree of the bending sensor 2 becomes larger, the resistance value of the bending sensor 2 gradually becomes smaller, and the resistance value of the bending sensor 2 is between 98 ohms and 103 ohms.

[0066] When the air with a speed of 7.14 m / s is delivered by the air supply assembly 101 on one side of the bending sensor 2 in the thickness direction, the bending degree of the bending sensor 2 becomes larger, the resistance value of the bending sensor 2 gradually becomes smaller, and the resistance value of the bending sensor 2 is between 91 ohms and 93 ohms.

[0067] When the air with a speed of 7.15 m / s is delivered by the air supply assembly 101 on one side of the bending sensor 2 in the thickness direction, the bending degree of the bending sensor 2 becomes larger, the resistance value of the bending sensor 2 gradually becomes smaller, and the resistance value of the bending sensor 2 is between 83 ohms and 86 ohms.

[0068] When the air with a speed of 7.40 m / s is delivered by the air supply assembly 101 on one side of the bending sensor 2 in the thickness direction, the bending degree of the bending sensor 2 becomes larger, the resistance value of the bending sensor 2 gradually becomes smaller, and the resistance value of the bending sensor 2 is between 78 ohms and 80 ohms.

[0069] According to the above experimental results, when the wind speed reaches 3.9 m / s or above, the bending sensor begins to bend and deform under the action of the pressure difference between the two sides. After the bending sensor begins to bend, the resistance rapidly decreases, and the resistance value of the bending sensor 2 decreases to below 2000 ohms.

[0070] When the wind speed reaches 4.6 m / s or above, the relationship between the wind speed and the resistance tends to be stable, which can be used to explore gas and liquid speed measurement or fluid flow measurement based on uniform cross-section.

[0071] The maximum wind speed at the air outlet 111 should be at least 4 m / s to ensure that the wind speed provided by the air supply assembly 101 can provide sufficient pressure difference to drive the bending sensor 2 to bend and deform.

[0072] In some embodiments, in order to more vividly and intuitively realize the visualization of Bernoulli principle, the Bernoulli principle visualization demonstration tool 100 further comprises a control module and an alarm device 7, the control module is in communication with the acquisition module 4 and the alarm device 7, and the control module controls the alarm device 7 to alarm when the resistance value acquired by the acquisition module 4 is lower than a preset value.

[0073] Therefore, through the Bernoulli principle visualization demonstration tool 100, the visualization demonstration of Bernoulli principle can be realized while the overspeed alarm is realized.

[0074] Specifically, taking the bending sensor 2 with a length of 195 mm, a width of 8 mm, and a thickness of 0.4 mm as an example, in the horizontal state, the resistance value of the bending sensor 2 is 25 kilo-ohms, and the resistance difference error of the bending sensor 2 is within 20%. The experimental process is as follows: first, the bending sensor 2 is fixed on one side of the first direction of the air supply assembly 101 and downstream of the air flow direction with the thickness direction perpendicular to the air flow direction. In order to ensure the accuracy of the data, the setting position of the bending sensor 2 in the radial direction of the air outlet 111 should be as close to the edge of the air outlet 111 as possible, and the distance from the air outlet 111 should also be as close as possible.

[0075] The control module is adjusted so that the alarm device 7 alarms when the resistance value acquired by the acquisition module 4 is lower than a certain preset value. For example, the control module is adjusted so that the alarm device 7 alarms when the resistance value acquired by the acquisition module 4 is lower than 2000 ohms, the air supply assembly 101 is controlled to be turned on, the air supply assembly 101 is controlled to supply air, and the air flow speed at the air outlet 111 is controlled to gradually increase. When the wind speed is lower than 3.9 m / s, the bending sensor 2 is not deformed or not obviously deformed, the resistance value is large, and the alarm device 7 does not alarm.

[0076] When the wind speed reaches 3.9 m / s or more, the bending sensor starts to bend and deform under the action of the pressure difference between the two sides. After the bending sensor starts to bend, the resistance rapidly decreases, the resistance value of the bending sensor 2 decreases to below 2000 ohms, and the alarm device 7 alarms when the acquisition module 4 acquires the information that the resistance value is lower than 2000 ohms.

[0077] At this time, the bending deformation of the bending sensor 2 can be directly observed through the bending sensor 2, and the information of the bending deformation of the bending sensor 2 can be obtained through the alarm of the alarm device 7, and the visualization demonstration of Bernoulli principle is more directly realized.

[0078] Meanwhile, the device can also realize overspeed alarm, and a preset value is selected according to the wind speed, for example, the alarm device 7 needs to start alarming when the wind speed reaches 5 m / s. The experimental process is that first, the bending sensor 2 is fixed on one side of the air supply assembly 101 in the first direction and downstream of the air flow direction in a manner that the thickness direction is perpendicular to the air flow direction. In order to ensure the accuracy of the data, the setting position of the bending sensor 2 in the radial direction of the air outlet 111 should be as close to the edge of the air outlet 111 as possible, and the distance from the air outlet 111 should also be as close as possible.

[0079] The adjustment control module controls the alarm device 7 to alarm when the resistance value acquired by the acquisition module 4 is lower than 250 ohms, controls the air supply assembly 101 to start, controls the air supply assembly 101 to supply air, and controls the air flow speed at the air outlet 111 to gradually increase. When the wind speed is lower than 5 m / s, the resistance value of the bending sensor 2 is greater than 250 ohms, and the alarm device 7 does not alarm. When the resistance value of the bending sensor 2 is less than 250 ohms, the alarm device 7 alarms after the acquisition module 4 acquires the information that the resistance value is lower than 250 ohms, that is, it can be judged that the wind speed reaches 5 m / s at this moment.

[0080] With reference to Figure 2 , the acquisition module 4 can also include a control circuit, the control circuit includes a power supply 8 circuit, a detection circuit and an alarm circuit, the power supply 8 circuit is used to provide the power supply 8, the alarm circuit is connected with the alarm device 7, and the power supply 8 circuit and the alarm circuit are respectively electrically connected with the detection circuit; the detection circuit includes the bending sensor 2, and the detection circuit is suitable for connecting the power supply 8 circuit and the alarm circuit when the bending sensor 2 bends.

[0081] The control circuit can be a traditional sensor sensing switch control circuit board, and the sensor sensing switch control circuit board is integrated with a relay, a variable resistor and the like. Before the bending sensor 2 bends and deforms, the resistance value of the bending sensor 2 is large, and the detection circuit is not conductive. After the bending sensor 2 bends and deforms, the resistance value of the bending sensor 2 is greatly reduced, the detection circuit is conductive, the power supply 8 circuit and the alarm circuit are connected, the power supply 8 supplies power to the alarm device 7, and the alarm device 7 starts to alarm.

[0082] The experimental process is that first, the bending sensor 2 is fixed on one side of the air supply assembly 101 in the first direction and downstream of the air flow direction in a manner that the thickness direction is perpendicular to the air flow direction. In order to ensure the accuracy of the data, the setting position of the bending sensor 2 in the radial direction of the air outlet 111 should be as close to the edge of the air outlet 111 as possible, and the distance from the air outlet 111 should also be as close as possible.

[0083] The power supply 8, the alarm device 7, the sensor sensing switch control circuit board and the bending sensor 2 are connected together through wires, for example, adjusting the rheostat on the sensing switch control circuit board, to ensure that the alarm device 7 can start alarming after the bending sensor 2 is bent, to control the air supply assembly 101 to start, to control the air supply assembly 101 to supply air, and to control the air flow rate at the air outlet 111 to gradually increase, when the wind speed is lower than 3.9 m / s, the bending sensor 2 is not deformed or the deformation is not obvious, the resistance value is large, and the alarm device 7 does not alarm.

[0084] When the wind speed reaches 3.9 m / s or above, the bending sensor starts to bend and deform under the action of the pressure difference on both sides, after the bending sensor starts to bend, the resistance rapidly decreases, the resistance value of the bending sensor 2 decreases to below 2000 ohms, until the resistance value of the bending sensor 2 decreases to be able to connect the power supply 8 circuit and the alarm circuit, the power supply 8 supplies power to the alarm device 7, and the alarm device 7 starts to alarm.

[0085] At this time, the bending deformation of the bending sensor 2 can be directly observed through the bending sensor 2, and the information of the bending deformation of the bending sensor 2 can be known through the alarm of the alarm device 7, and the Bernoulli principle visualization demonstration is more directly realized.

[0086] In some embodiments, the air supply assembly 101 includes a housing 11 and a fan, the housing 11 defines an air duct, and the air outlet 111 is provided on one side of the housing 11 in the first direction and communicates with the air duct, the fan is arranged in the air duct, the air flow in the air duct is driven by the rotation of the fan, the wind speed at the air outlet 111 is controlled by controlling the rotating speed of the fan, and the controllable air supply speed of the air supply assembly 101 is realized.

[0087] As shown in Figure 2 The Bernoulli principle visualization demonstration teaching aid 100 further includes a fixed support 3, the air supply assembly 101 is fixedly arranged on the fixed support 3 through a first fixing member, and the bending sensor 2 is fixedly arranged on the fixed support 3 through a second fixing member, so as to ensure that the relative position between the bending sensor 2 and the air outlet 111 is unchanged, and the accuracy of the experimental results is ensured.

[0088] In some embodiments, the air supply assembly 101 is a blower 102, the blower 102 has an irregular shape and is difficult to fix, and the first fixing member can include a binding strap 5 to simplify the fixing difficulty and ensure the stability of the fixing.

[0089] The second fixing member can include a fixing clamp 6 to simplify the fixing difficulty, ensure the stability of the fixing, and ensure that the posture of the bending sensor 2 can be maintained in the state of extending along the vertical direction.

[0090] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the illustrative use of the above terms does not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0091] Although the embodiments of the present invention have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and purpose of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A visual demonstration teaching aid for Bernoulli's principle, characterized in that: include: An air supply component having an air outlet, wherein the wind speed at the air outlet of the air supply component is adjustable; a bending sensor, the bending sensor being disposed on one side of the air supply assembly in a first direction and downstream of the air outlet in the direction of the airflow, the first direction being perpendicular to the direction of the airflow, and the bending sensor being bent toward a side closer to the air supply assembly under the action of the airflow; An acquisition module is connected to the bending sensor and is used to acquire the resistance of the bending sensor.

2. The Bernoulli principle visualization demonstration teaching aid according to claim 1, characterized in that: The thickness direction of the bending sensor is perpendicular to the airflow direction; and / or, the bending sensor is bent toward one side in the thickness direction, and a direction mark is provided on at least one of the two side surfaces of the bending sensor in the thickness direction; And / or, in an unstressed state, a projection of the bending sensor on the plane where the air outlet is located is located at an edge of the air outlet or outside the air outlet.

3. The Bernoulli principle visualization demonstration teaching aid according to claim 1, characterized in that: The axial distance between the bending sensor and the air outlet is less than 15 cm; And / or, a radial distance between the bending sensor and the air outlet is less than 8 cm.

4. The visual demonstration teaching aid for Bernoulli's principle according to claim 1, characterized in that: The air outlet is a circular air outlet, and the diameter of the air outlet is less than half the length of the bending sensor.

5. The Bernoulli principle visualization demonstration teaching aid according to claim 1, characterized in that: The air supply assembly includes a housing and a fan, wherein the housing defines an air outlet duct and an air outlet communicating with the air outlet is formed on one side of the housing in a first direction, and the fan is disposed in the air outlet duct; And / or, the maximum wind speed at the air outlet is not less than 4m / s.

6. The visual demonstration teaching aid for Bernoulli's principle according to claim 1, characterized in that: Also includes: A control module and an alarm device, wherein the control module communicates with the acquisition module and the alarm device, and controls the alarm device to sound an alarm when the resistance value acquired by the acquisition module is lower than a preset value.

7. The Bernoulli principle visualization demonstration teaching aid according to claim 1, characterized in that: The acquisition module includes a resistance measuring instrument.

8. The visual demonstration teaching aid for Bernoulli's principle according to claim 1, characterized in that: The acquisition module also includes a control circuit, which includes a power supply circuit, a detection circuit and an alarm circuit. The power supply circuit is used to provide power, and the alarm circuit is connected to an alarm device. The power supply circuit and the alarm circuit are respectively electrically connected to the detection circuit; the detection circuit includes the bending sensor, and the detection circuit is suitable for connecting the power supply circuit and the alarm circuit when the bending sensor is bent.

9. The Bernoulli principle visualization demonstration teaching aid according to claim 1, characterized in that: It also includes a fixed bracket, the air supply component is fixedly arranged on the fixed bracket through a first fixing piece, and the bending sensor is fixedly arranged on the fixed bracket through a second fixing piece.

10. The visual demonstration teaching aid for Bernoulli's principle according to claim 9, characterized in that: The first fixing member includes a strap; and / or the second fixing member includes a fixing clip; and / or the air supply assembly includes a blower.

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