Experiment teaching device for measuring gravitational acceleration

Abstract

The utility model provides an experiment teaching device for measuring gravitational acceleration, which relates to the technical field of physics teaching experiment devices and comprises a base, a supporting module, a main control module and a ball falling module. Each magnetic Hall switch of the ball falling module is arranged on a first fixing rod, a non-magnetic small ball is adsorbed below each magnetic Hall switch, and a pressure sensor is arranged under each non-magnetic small ball; the main control module is used for controlling the (i + 1) th magnetic Hall switch to release the adsorbed non-magnetic small ball when the ith pressure sensor is triggered; and the timing module is used for starting timing when the first pressure sensor is triggered and ending timing when the Nth pressure sensor is triggered so as to determine the time from the beginning of falling of the second non-magnetic small ball to the ending of falling of the Nth non-magnetic small ball. The scheme is convenient and fast, the time measurement accuracy is higher, and the measurement efficiency and the measurement accuracy of the gravitational acceleration can be improved.

Description

Technical Field

[0001] The utility model relates to the technical field of physics teaching experimental devices, in particular to an experimental teaching device for measuring gravity acceleration. Background Art

[0002] Gravitational acceleration is a basic vector in geophysical research and an important parameter that needs to be considered when conducting mechanical analysis on general mechanical systems. The measurement of gravitational acceleration is of great significance to physics, geophysics, gravity prospecting, space science, etc. Therefore, the measurement demonstration experiment of gravitational acceleration has also become an important experiment for middle schools and universities to explore gravitational acceleration.

[0003] The first person to measure the acceleration of gravity was Galileo, who used a method to change the measurement of the acceleration of gravity g to the measurement of the tiny acceleration a=gsinθ, where θ is the inclination angle of the inclined plane; the second was Atwood, who used a method to connect heavy blocks of the same mass M with ropes, placed them on a smooth light pulley, and then added a much smaller mass m on top of the heavy block to produce a tiny acceleration of gravity. Both of the above scientists used the tiny method to measure the acceleration of gravity, providing the initial scheme for measuring the acceleration of gravity.

[0004] At present, the falling ball method is commonly used in the gravity acceleration measurement experiment in schools to measure gravity acceleration, that is, by letting the ball do free fall motion, the gravity acceleration is calculated by the falling distance and time. The principle is simple, intuitive and easy to demonstrate, but this method has a short falling time and a large error in measuring time. Later, in order to reduce the error in measuring time, dotting timers were gradually applied to gravity acceleration measurement experiments. Although this method has solved the problem of short time and inaccurate measurement to a certain extent, it ignores the friction between the paper tape and the dotting timer, making the time measurement accuracy poor. In addition, because the distance between each dotting point needs to be measured multiple times, the measurement becomes more cumbersome, the measurement takes a long time, and the measurement efficiency is low. Utility Model Content

[0005] In view of this, in order to address the above shortcomings, it is necessary to propose an experimental teaching device for measuring gravitational acceleration that is convenient and fast and has higher time measurement accuracy, so as to improve the measurement efficiency and accuracy of gravitational acceleration.

[0006] The utility model provides an experimental teaching device for measuring gravitational acceleration, comprising: a base, a support module, a main control module and a ball-dropping module; the support module comprises a first bracket, a second bracket and a first fixing rod, the first bracket and the second bracket are both vertically fixed on the base, and the two ends of the first fixing rod are respectively connected to the upper ends of the first bracket and the second bracket; the ball-dropping module comprises N magnetic Hall switches, N non-magnetic balls and N pressure sensors, the N magnetic Hall switches are evenly distributed on the first fixing rod, a non-magnetic ball is adsorbed below each magnetic Hall switch, a pressure sensor is arranged directly below each non-magnetic ball, and the non-magnetic ball on the magnetic Hall switch can fall on the corresponding pressure sensor below when falling; the main control module is electrically connected to the N magnetic Hall switches and the N pressure sensors respectively; N≥3, and N is an integer;

[0007] The main control module is used to control the i+1th magnetic Hall switch to release the adsorbed non-magnetic ball when the i-th pressure sensor is triggered; and to start timing when the first pressure sensor is triggered by the pressure generated by the falling non-magnetic ball, and to end timing when the N-th pressure sensor is triggered by the pressure generated by the falling non-magnetic ball, so as to determine the time taken from the start of the falling of the second non-magnetic ball to the end of the falling of the N-th non-magnetic ball; wherein 1≤i≤N-1, and i is an integer.

[0008] Preferably, both ends of the first fixing rod are movably connected to the first bracket and the second bracket so as to be adjustable along the direction of the bracket.

[0009] Preferably, the device also includes a positioning module; the positioning module includes at least one second fixed rod and N ball drop tubes, and both ends of each second fixed rod are movably connected to the first bracket and the second bracket respectively, and both can be adjusted along the bracket direction; a ball drop tube is arranged under each of the non-magnetic balls, and the ball drop tube is adjustably fixed on the second fixed rod, and the upper end opening of each ball drop tube faces a non-magnetic ball, and the lower end opening faces the pressure sensor corresponding to the non-magnetic ball.

[0010] Preferably, the ball drop tube is made of a transparent acrylic plate.

[0011] Preferably, the device also includes a ball collection groove, which is a U-shaped structure; the opening of the ball collection groove is upward, and the two ends are respectively fixedly connected to the first bracket and the second bracket, and N pressure sensors are distributed and fixedly arranged in the U-shaped groove.

[0012] Preferably, the U-shaped groove is open at one end close to the first bracket and closed at one end close to the second bracket, and there is a gap between each pressure sensor and the bottom of the inner side of the U-shaped groove, which can allow non-magnetic balls to pass through.

[0013] Preferably, a display module is also provided on the base, which is electrically connected to the main control module and is used to display the time taken from the start of the fall of the second non-magnetic ball to the end of the fall of the Nth non-magnetic ball determined by the main control module.

[0014] Preferably, the device further comprises a trigger button; the trigger button is electrically connected to the first magnetic Hall switch and is used for releasing the non-magnetic ball adsorbed by the first magnetic Hall switch after being triggered by an operator.

[0015] Preferably, the first bracket and / or the second bracket are provided with scales.

[0016] Preferably, the device further comprises a power supply module fixedly arranged on the base, wherein the power supply module is electrically connected to each electrical component to supply power to each electrical component.

[0017] It can be seen from the above technical scheme that the experimental teaching device for measuring gravitational acceleration provided by the embodiment of the utility model includes a base, a support module, a main control module and a falling ball module, wherein the falling ball module is fixed on the first fixed rod of the support module, and N magnetic Hall switches electrically connected to the main control module are fixedly installed on the first fixed rod, and a non-magnetic ball is adsorbed on each magnetic switch, and a pressure sensor electrically connected to the main control module is arranged directly below each non-magnetic ball. The main control module can control the i+1th magnetic Hall switch to release the adsorbed ball when the i-th pressure sensor is triggered, and can start timing when the first pressure sensor is triggered by the pressure generated by the falling non-magnetic ball, and end timing when the N-th pressure sensor is triggered by the pressure generated by the falling non-magnetic ball. In this way, the first magnetic Hall switch is triggered to release the adsorbed non-magnetic ball, and the non-magnetic ball falls on the first pressure sensor. At this time, the main control module starts timing, and the first pressure sensor is triggered to cause the second magnetic Hall switch to release the adsorbed non-magnetic ball. In this way, each non-magnetic ball is released in turn until the Nth non-magnetic ball falls on the Nth pressure sensor and the timing ends. In this way, the time between the start of the second non-magnetic ball and the end of the Nth non-magnetic ball falling is obtained, and the gravity acceleration can be calculated by further combining the distance between the magnetic Hall switch and the pressure sensor. It can be seen that the measurement of this scheme is simple and convenient, and does not require frequent distance measurement, thereby improving the measurement efficiency of gravity acceleration. Moreover, the measurement of time will not be affected by friction compared to the dot timing method, so the measured time is more accurate, which can improve the measurement accuracy of gravity acceleration. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1The present invention is a three-dimensional schematic diagram of an experimental teaching device for measuring gravitational acceleration provided by an embodiment of the present invention.

[0019] Figure 2 A top view of an experimental teaching device for measuring gravitational acceleration provided by an embodiment of the utility model.

[0020] In the figure: base 10, support module 20, first bracket 21, second bracket 22, first fixing rod 23, main control module 30, ball falling module 40, magnetic Hall switch 41, non-magnetic ball 42, pressure sensor 43, display module 50, positioning module 60, second fixing rod 61, ball falling tube 62, ball collecting groove 70, power supply module 80, wire tube 90, trigger button 100. DETAILED DESCRIPTION

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0022] See also Figure 1-2 The embodiment of the utility model provides an experimental teaching device for measuring gravitational acceleration, comprising: a base 10, a support module 20, a main control module 30 and a ball-dropping module 40; the support module 20 comprises a first bracket 21, a second bracket 22 and a first fixing rod 23, the first bracket 21 and the second bracket 22 are both vertically fixed on the base 10, and the two ends of the first fixing rod 23 are respectively connected to the upper ends of the first bracket 21 and the second bracket 22; the ball-dropping module 40 comprises N magnetic Hall switches 41, N non-magnetic balls 42 and N pressure sensors 43, the N magnetic Hall switches 41 are evenly distributed on the first fixing rod 23, a non-magnetic ball 42 is adsorbed below each magnetic Hall switch 41, a pressure sensor 43 is arranged directly below each non-magnetic ball 42, and the non-magnetic ball 42 on the magnetic Hall switch 41 can fall on the corresponding pressure sensor 43 below when falling; the main control module 30 is electrically connected to the N magnetic Hall switches 41 and the N pressure sensors 43 respectively; N≥3, and N is an integer;

[0023] The main control module 30 is used to control the i+1th magnetic Hall switch 41 to release the adsorbed non-magnetic ball 42 when the i-th pressure sensor 43 is triggered; and to start timing when the first pressure sensor 43 is triggered by the pressure generated by the falling non-magnetic ball 42, and to end timing when the N-th pressure sensor 43 is triggered by the pressure generated by the falling non-magnetic ball 42, so as to determine the time taken from the start of the falling of the second non-magnetic ball 42 to the end of the falling of the N-th non-magnetic ball 42; wherein 1≤i≤N-1, and i is an integer.

[0024] In this embodiment, the main control module 30 can control the i+1th magnetic Hall switch 41 to release the adsorbed ball when the i-th pressure sensor 43 is triggered, and can start timing when the first pressure sensor 43 is triggered by the pressure generated by the falling of the non-magnetic ball 42, and end timing when the N-th pressure sensor 43 is triggered by the pressure generated by the falling of the non-magnetic ball 42. In this way, the first magnetic Hall switch 41 is triggered to release the adsorbed non-magnetic ball 42, and the non-magnetic ball 42 falls on the first pressure sensor 43. At this time, the main control module 30 starts timing, and at the same time, the first pressure sensor 43 is triggered to cause the second magnetic Hall switch 41 to release the adsorbed non-magnetic ball 42, so that each non-magnetic ball 42 is released in turn until the N-th non-magnetic ball 42 falls on the N-th pressure sensor 43 and the timing ends. In this way, the time from the second non-magnetic ball 42 starting to fall to the Nth non-magnetic ball 42 finishing falling is obtained, and the gravity acceleration can be calculated by further combining the distance between the magnetic Hall switch 41 and the pressure sensor 43. It can be seen that the measurement of this scheme is simple and convenient, and does not require frequent distance measurement, thereby improving the measurement efficiency of gravity acceleration. Moreover, compared with the dot timing method, the measurement of time will not be affected by friction, so the measured time is more accurate, which can improve the measurement accuracy of gravity acceleration.

[0025] When calculating the gravitational acceleration, assuming that the total time for the last n balls to fall is t, then the falling time of each ball is The height of the magnetic Hall switch 41 from the pressure sensor 43 is h. According to the free fall motion displacement formula: Can be pushed Therefore In this scheme, n = N-1, then That is, the value of gravitational acceleration can be calculated based on this formula.

[0026] Furthermore, the device further includes a trigger button 100; the trigger button 100 is electrically connected to the first magnetic Hall switch 41, and is used to release the non-magnetic ball 42 adsorbed by the first magnetic Hall switch 41 after being triggered by an operator. In this way, the operator can release the non-magnetic ball 42 adsorbed by the first magnetic Hall switch 41 by pressing the trigger button 100 to start the measurement experiment.

[0027] Of course, it should be pointed out that the N non-magnetic balls 42 should be completely identical.

[0028] In addition, a scale may be set on the first bracket 21 and / or the second bracket 22, so that the operator can directly read the height h from the scale on the first bracket 21 or the second bracket 22, that is, read the falling height of the non-magnetic ball 42, saving the operator's measurement time. Of course, the first bracket 21 and the second bracket 22 can be made of a transparent acrylic plate, which is not only low in cost and has sufficient strength, but also convenient for setting the scale.

[0029] Further, the base 10 is also provided with a display module 50, which is electrically connected to the main control module 30, and is used to display the time taken from the second non-magnetic ball 42 determined by the main control module 30 to the end of the falling of the Nth non-magnetic ball 42. In this way, the main control module 30 can display the total time taken for the measured N-1 non-magnetic balls 42 to fall through the display module 50 after the measurement is completed. The operator can directly read the time from the display module 50 to directly bring it into the formula for calculation, without connecting to the host computer and other equipment for time display, which is convenient and fast. The display module 50 can be a digital display tube, an LCD display, an OLED liquid crystal display, etc. The main control module 30 can use a Mego2560 core main control board with a high-precision timing function.

[0030] In one embodiment, in order to facilitate the adjustment of the falling height of the non-magnetic ball 42, both ends of the first fixing rod 23 are movablely connected to the first bracket 21 and the second bracket 22 in an adjustable direction along the bracket. In this way, the operator can adjust the height of the first fixing rod 23 according to the experimental requirements, thereby adjusting the falling height of the non-magnetic ball 42.

[0031] In order to prevent the falling non-magnetic ball 42 from deviating from the falling path due to various reasons and failing to fall onto the pressure sensor 43 below, thereby causing the next magnetic Hall switch 41 to fail to be triggered or causing a timing error, the present scheme considers setting up a positioning module 60, which includes at least one second fixed rod 61 and N ball drop tubes 62, and both ends of each second fixed rod 61 are movably connected to the first bracket 21 and the second bracket 22, respectively, and both can be adjusted along the bracket direction; a ball drop tube 62 is arranged under each non-magnetic ball 42, and the ball drop tube 62 is adjustably fixed on the second fixed rod 61, and the upper end opening of each ball drop tube 62 is opposite to a non-magnetic ball 42, and the lower end opening is opposite to the pressure sensor 43 corresponding to the non-magnetic ball 42.

[0032] In this embodiment, a ball drop tube 62 is provided, and the openings at both ends of the ball drop tube 62 are respectively facing the non-magnetic ball 42 above and the pressure sensor 43 below, so that the ball will not deviate from the falling path and fail to fall on the pressure sensor 43, thereby ensuring the success rate of the experiment.

[0033] Furthermore, the ball drop tube 62 can be made of a transparent acrylic plate, which makes it convenient for operators to observe the falling of the ball, which can not only deepen the understanding of the gravity acceleration measurement experiment, but also determine the reliability of the current experimental data.

[0034] In one embodiment, in order to avoid the non-magnetic balls 42 from being scattered everywhere after falling, it takes more time to collect the non-magnetic balls 42. This solution considers setting up a ball collection groove 70, which is a U-shaped structure; the opening of the ball collection groove 70 is upward, and the two ends are respectively fixedly connected to the first bracket 21 and the second bracket 22, and N pressure sensors 43 are distributed and fixedly arranged in the U-shaped groove. In addition, the U-shaped groove is open at one end close to the first bracket 21, and closed at one end close to the second bracket 22. There is a gap between each pressure sensor 43 and the bottom of the inner side of the U-shaped groove, and it can meet the non-magnetic balls 42. When the experiment is over, the non-magnetic balls 42 can be taken out from the open end of the U-shaped groove. In this way, the non-magnetic balls 42 will enter the U-shaped groove after falling, and will not be scattered everywhere, so there is no need to spend extra time to find and collect the non-magnetic balls 42, and it will not affect the next set of experiments.

[0035] Of course, in one embodiment, the device further includes a power supply module 80 fixedly disposed on the base 10, and the power supply module 80 is electrically connected to each electrical component to supply power to each electrical component. The cable between the magnetic Hall switch 41 and the main control module 30 can be arranged by setting a wire tube 90 to make the device more compact and beautiful.

[0036] In addition, it should be pointed out that the order of the 1st to the Nth pressure sensors, magnetic Hall switches or non-magnetic balls mentioned in the text is defined according to the order of actual installation and setting, such as Figure 1 As shown in the figure, the 1st to 6th ones can be defined from left to right in the figure. It is easy to understand that the magnetic Hall switch, the non-magnetic ball and the pressure sensor should have a corresponding relationship. For example, the non-magnetic ball adsorbed under the first magnetic Hall switch is the first non-magnetic ball, and the pressure sensor directly below is the first pressure sensor.

[0037] When conducting the experiment, after connecting the above devices, you can perform the experimental operation through the following steps:

[0038] 1) Install the experimental instrument on a horizontal table and check the stability of each bracket and fixing rod;

[0039] 2) Adjust the height of the first fixing rod 23 so that the magnetic Hall switch 41 is at a suitable height, and use a leveling instrument to check whether the magnetic Hall switch 41 is at the same height;

[0040] 3) Turn on the power supply to ensure that each magnetic Hall switch 41 and pressure sensor 43 work normally, so that all magnetic Hall switches 41 are in a closed state. Even if the magnetic Hall switch 41 is magnetic, place a non-magnetic ball 42 at the bottom of the magnetic Hall switch 41;

[0041] 4) Press the trigger button to start the experiment;

[0042] 5) After the balls finish falling one by one, read the time on the display screen;

[0043] 6) Substitute the measured data into the formula to calculate the acceleration due to gravity;

[0044] 7) Repeat the above experimental steps;

[0045] 8) Arrange experimental equipment;

[0046] 9) Analyze experimental errors.

[0047] The modules or units in the device of the embodiment of the utility model can be combined, divided and deleted according to actual needs. The above disclosure is only the preferred embodiment of the utility model, and of course it cannot be used to limit the scope of the rights of the utility model. Ordinary technicians in this field can understand that all or part of the processes of the above embodiments are implemented, and equivalent changes made according to the claims of the utility model still fall within the scope of the utility model.

Claims

1. An experimental teaching device for measuring gravitational acceleration, characterized in that: include: Base, support module, main control module and ball drop module; The support module includes a first bracket, a second bracket and a first fixing rod, the first bracket and the second bracket are both vertically fixed on the base, and the two ends of the first fixing rod are respectively connected to the upper ends of the first bracket and the second bracket; the ball falling module includes N magnetic Hall switches, N non-magnetic balls and N pressure sensors, the N magnetic Hall switches are evenly distributed on the first fixing rod, a non-magnetic ball is adsorbed under each magnetic Hall switch, a pressure sensor is arranged directly under each non-magnetic ball, and the non-magnetic ball on the magnetic Hall switch can fall on the corresponding pressure sensor below when falling; the main control module is electrically connected to the N magnetic Hall switches and the N pressure sensors respectively; N≥3, and N is an integer; The main control module is used to control the i+1th magnetic Hall switch to release the adsorbed non-magnetic ball when the i-th pressure sensor is triggered; and to start timing when the first pressure sensor is triggered by the pressure generated by the falling non-magnetic ball, and to end timing when the N-th pressure sensor is triggered by the pressure generated by the falling non-magnetic ball, so as to determine the time taken from the start of the falling of the second non-magnetic ball to the end of the falling of the N-th non-magnetic ball; wherein 1≤i≤N-1, and i is an integer.

2. The experimental teaching device for measuring gravitational acceleration according to claim 1, characterized in that: Both ends of the first fixing rod are movably connected to the first bracket and the second bracket so as to be adjustable along the direction of the bracket.

3. The experimental teaching device for measuring gravitational acceleration according to claim 2, characterized in that: The device also includes a positioning module; the positioning module includes at least one second fixed rod and N ball drop tubes, and both ends of each second fixed rod are movably connected to the first bracket and the second bracket respectively, and both can be adjusted along the bracket direction; a ball drop tube is arranged under each of the non-magnetic balls, and the ball drop tube is adjustably fixed on the second fixed rod, and the upper end opening of each ball drop tube faces a non-magnetic ball, and the lower end opening faces the pressure sensor corresponding to the non-magnetic ball.

4. The experimental teaching device for measuring gravitational acceleration according to claim 3, characterized in that: The ball drop tube is made of a transparent acrylic plate.

5. The experimental teaching device for measuring gravitational acceleration according to claim 1, characterized in that: The device also includes a ball collection groove, which is a U-shaped structure; the opening of the ball collection groove is upward, and the two ends are respectively fixedly connected to the first bracket and the second bracket, and N pressure sensors are distributed and fixedly arranged in the U-shaped groove.

6. The experimental teaching device for measuring gravitational acceleration according to claim 5, characterized in that: The U-shaped groove is open at one end close to the first bracket and closed at one end close to the second bracket. There is a gap between each of the pressure sensors and the bottom of the inner side of the U-shaped groove, and a non-magnetic ball can pass through.

7. The experimental teaching device for measuring gravitational acceleration according to claim 1, characterized in that: The base is also provided with a display module, which is electrically connected to the main control module and is used to display the time taken between the start of the fall of the second non-magnetic ball and the end of the fall of the Nth non-magnetic ball determined by the main control module.

8. The experimental teaching device for measuring gravitational acceleration according to claim 1, characterized in that: The device also includes a trigger button; the trigger button is electrically connected to the first magnetic Hall switch and is used to release the non-magnetic ball adsorbed by the first magnetic Hall switch after being triggered by an operator.

9. The experimental teaching device for measuring gravitational acceleration according to claim 1, characterized in that: The first bracket and / or the second bracket are provided with scales.

10. The experimental teaching device for measuring gravitational acceleration according to any one of claims 1 to 9, characterized in that: The device also includes a power supply module fixedly arranged on the base, and the power supply module is electrically connected to each electrical component to supply power to each electrical component.

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