Demonstration experiment device and method for verifying Biot-Savart law

Abstract

The invention belongs to the technical field of electromagnetism experiment teaching instruments, and particularly relates to a demonstration experiment device and method for verifying the Biot-Savart law. The device is reasonable in design, the geomagnetic field serves as a reference magnetic field, indirect measurement of the magnetic induction intensity around the current-carrying wire is achieved by measuring the deflection angle of the magnetic needle under the action of the current-carrying wire according to the vector superposition principle of the magnetic field, a traditional measurement mode depending on a Hall sensor or a fluxmeter is replaced, and the measurement accuracy is improved. A measurement basis is provided for a verification experiment of the Biot-Savart law; the device is structurally composed of an angle positioning bottom plate, a current-carrying wire assembly and a magnetic needle measuring assembly, the relative magnetic induction intensity is obtained through visual angle reading, and data calculation is achieved in combination with the magnetic field vector superposition relation. By measuring the relationship between the magnetic induction intensity on the symmetry axis of the current-carrying bent conductor and the vertical distance, the current magnitude and the bending angle, experimental verification demonstration of the Biot-Savart law is realized.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electromagnetic experiment teaching instruments, and particularly relates to a demonstration experiment device and method for verifying the Biot-Savart law. BACKGROUND

[0002] Biot and Savart first set a compensating magnet to offset the influence of the geomagnetic field, and measured the force of the current-carrying conductor on the magnetic needle by using the periodic oscillation method, and obtained that the square of the oscillation period of the magnetic needle is proportional to the vertical distance of the magnetic needle to the current-carrying straight conductor. They also designed to measure the relationship between the force of the magnetic pole on the angle bisector of the bending conductor and the change of the bending angle, obtained the quantitative expression of the force of the bending conductor on the magnetic pole, and obtained the Biot-Savart law with the help of Laplace's theoretical analysis. The experiment lays the foundation for the quantitative conclusion of the current magnetic effect in theory, but the experimental device is relatively complex, the operation steps are cumbersome, and there are many influencing factors, which is difficult to reproduce in ordinary teaching scenes.

[0003] The accurate measurement of the magnetic field around the current-carrying conductor is the cornerstone of verifying the Biot-Savart law and Ampere's loop theorem and other core theories of electromagnetism, and is also an important experimental measurement basis in university physics experiment teaching, and has certain value in scientific research and engineering technology application. However, a fundamental challenge is that the magnetic induction intensity generated by the ordinary current-carrying straight conductor in the near field is usually of the order of microtesla (μT), which is comparable to the strength of the horizontal component of the geomagnetic field (about 20-65 μT). Thus, the target magnetic field signal is easily overwhelmed by the geomagnetic field, making direct measurement difficult.

[0004] With the development of measurement technology, weak magnetic field measurement gradually turns to electronicization. In the prior art, electronic measurement devices such as Hall sensors, magnetic flux sensors, magnetoresistance sensors or high-sensitivity magnetometers are commonly used. Although these instruments have high precision, they have problems such as high cost, poor anti-interference performance and weak environmental adaptability. For example: 1) the precision of the commonly used gauss meter (about 10 μT) cannot meet the precision requirements of the experiment, and high-precision magnetic field strength devices are expensive and not suitable for popularization of basic teaching experiments; 2) the sensor is highly sensitive to position and angle, and is obviously responsive to external electromagnetic noise; 3) zero-point calibration and temperature drift correction are required before measurement; 4) most of them are point measurement type detection methods, which are difficult to directly display the magnetic field distribution characteristics, and are not conducive to students' understanding of the concept of magnetic field vector.

[0005] To eliminate the influence of the geomagnetic field, the traditional method often adopts a compensation magnetic field scheme, for example, a uniform magnetic field is generated by using a Helmholtz coil to offset the geomagnetic field, or a reverse magnetic field is generated by using a permanent magnet to compensate. Although the compensation method can improve the measurement sensitivity, it still has the disadvantages of complex structure, large volume, high precision requirement for installation and adjustment, obvious magnetic hysteresis effect, and small measurable space range. Especially in the teaching scene, the Helmholtz coil system has very high requirements for the space environment and geometric symmetry, which is not conducive to students to independently build and operate. Some teaching experiments also qualitatively observe the current magnetic field direction by using a magnetic needle to illustrate electromagnetic interaction, but only the direction change of the magnetic field can be reflected, and the quantitative measurement of the magnetic induction intensity cannot be realized. Due to the superimposed influence of the geomagnetic background, the magnetic needle deflection is difficult to directly correspond to the theoretical value, thereby limiting the application of the method in quantitative research and accurate verification.

[0006] Therefore, in the prior art system, the experimental verification of the Biot-Savart law still mainly depends on high-precision electronic measurement or a complex compensation system. There is a lack of a teaching-type experimental device which is simple in structure, low in cost, and capable of realizing quantitative measurement of the magnetic field intensity under the geomagnetic background. SUMMARY

[0007] The purpose of the present application is to overcome the above-mentioned problems in the prior art, and to provide a demonstration experiment device and method for verifying the Biot-Savart law. By using the magnetic needle deflection angle to indirectly calculate the magnetic induction intensity under the condition of superposition of the geomagnetic field and the current-carrying wire magnetic field, the quantitative verification of the Biot-Savart law is realized. This method avoids complex compensation structure and expensive sensing equipment, and has the characteristics of simple device, intuitive measurement, low cost, and strong repeatability, and is especially suitable for university basic physics experiments and weak magnetic field measurement teaching, and has both theoretical rigor and operational feasibility.

[0008] To achieve the above technical purposes and effects, the present application is realized by the following technical solutions:

[0009] The present application provides a demonstration experiment device for verifying the Biot-Savart law, comprising:

[0010] An angle positioning bottom plate is used to establish a reference measurement plane, and a direction reference line consistent with the north-south direction of the geomagnetic field is arranged on the bottom plate, and a measurement scale structure for recording the bending angle of the wire α and the distance between the magnetic needle and the wire r is arranged on the bottom plate;

[0011] A current-carrying wire assembly comprises a bendable wire with a central angle of 2 α , and a stabilized direct current power supply connected to both ends of the wire; the plane of the bendable wire is perpendicular and coplanar with the direction reference line, and the stabilized direct current power supply is used to provide the required current for measurementI ;

[0012] A magnetic needle measuring assembly is arranged at a measuring position directly above the bending point of the current-carrying conductor assembly, and a magnetic needle of the magnetic needle measuring assembly can rotate freely around a vertical axis, indicating the direction of the magnetic field and measuring the deflection angle.

[0013] Further, in the demonstration experiment device for verifying the Biot-Savart law, the direction of the magnetic induction intensity generated by the current-carrying conductor assembly is kept perpendicular to the horizontal component direction of the geomagnetic field, so that the magnetic needle deflects under the combined magnetic field of the geomagnetic field and the magnetic field of the current-carrying conductor, thereby realizing indirect measurement of the magnetic induction intensity.

[0014] Further, in the demonstration experiment device for verifying the Biot-Savart law, the magnetic needle measuring assembly adopts a high-sensitivity compass, and the vertical distance between the center of the magnetic needle and the bending point of the conductor is accurately limited through an adjustable support r to improve the measurement repeatability.

[0015] Further, in the demonstration experiment device for verifying the Biot-Savart law, the current-carrying conductor assembly is made of oxygen-free copper wire and is fixed through symmetrically arranged insulation support structures, and the conductor connection part extends in a direction perpendicular to the plane of the conductor, so as to reduce the interference of the connected current on the magnetic field in the measurement area; in order to avoid interference of the excess conductor, the current-carrying conductor assembly adopts a conductor with a length of about 5000 mm and is fixed with a 1000 mm wooden stick on both sides of the midpoint, thereby limiting the effective measurement section, and the remaining part is used as a connecting wire.

[0016] The application also provides a demonstration experiment method for verifying the Biot-Savart law, which is realized based on the demonstration experiment device for verifying the Biot-Savart law and includes the following steps:

[0017] 1) Read the initial deflection direction of the magnetic needle in the state without current, obtain the horizontal component direction of the geomagnetic field, and vertically fix the angle positioning bottom plate in the direction parallel to the geomagnetic field;

[0018] 2) Fix the current-carrying conductor at the corresponding bending angle , connect the current I , so that the current-carrying conductor generates a magnetic field;

[0019] 3) Record the deflection angle of the magnetic needle in the steady state ;

[0020] 4) Calculate the magnetic induction intensity of the current-carrying conductor based on the superposition relationship of the magnetic field vectors B c :

[0021]

[0022] Biot-Savart law. is the horizontal component of the geomagnetic field, is the deflection angle of the magnetic needle.

[0023] Further, the demonstration experiment method for verifying the Biot-Savart law as described above, by changing the current I records the deflection angle of the magnetic needle, and verifies the magnetic induction intensity B c is proportional to the current. I

[0024] Further, the demonstration experiment method for verifying the Biot-Savart law as described above, by changing the distance r records the deflection angle, and verifies the magnetic induction intensity B c is inversely proportional to the distance. r

[0025] Further, the demonstration experiment method for verifying the Biot-Savart law as described above, in the bent wire configuration, records the deflection angle of the magnetic needle under different included angles 2 α verifies B c is proportional to tan( α / 2).

[0026] Further, the demonstration experiment method for verifying the Biot-Savart law as described above, the magnetic needle and the wire are always arranged in the same plane to ensure that the magnetic field superposition is a two-dimensional model, and the vertical component of the geomagnetic field has a negligible effect on the deflection, thereby improving the measurement accuracy.

[0027] The application also provides a demonstration experiment device for verifying the Biot-Savart law, which is applied to quantitative measurement of the magnetic field distribution around the current-carrying wire in university physics teaching experiments and verification of the Biot-Savart law.

[0028] The application has the following beneficial effects:

[0029] 1. The weak magnetic field can be quantitatively measured without a magnetic field compensation system, simplifying the structure and operation process.

[0030] 2. The mechanical magnetic needle measurement method is used instead of the electronic sensing system, reducing the cost and improving the reliability.

[0031] 3. The quantitative law of the magnetic field and the current, distance, and spatial geometric relationship is more easily observed and understood through the intuitive indication of the deflection angle of the magnetic needle, significantly improving the visualization effect of the teaching experiment.

[0032] 4. The device is simple in structure and easy to build, and can be implemented in a general physics laboratory without the support of professional magnetic shielding or precise measurement equipment.

[0033] ​​Of course, implementing any product of the present application does not necessarily require achieving all of the above advantages at the same time. BRIEF DESCRIPTION OF DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed for the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and all other drawings obtained by those of ordinary skill in the art without creative effort based on these drawings also belong to the protection scope of the present application.

[0035] Figure 1 It is a schematic diagram of the device of the present application as a whole.

[0036] Figure 2 It is a schematic diagram of the angle positioning base plate in the present application.

[0037] Figure 3 It is a schematic diagram of the current-carrying wire assembly in the present application.

[0038] Figure 4 It is a schematic diagram of the magnetic needle measurement assembly in the present application.

[0039] Figure 5 It is a flow chart of the experimental measurement steps of the device of the present application.

[0040] Figure 6 It is a curve diagram of the relative value of magnetic induction intensity changing with current and vertical distance under the experimental condition of straight wire of the device of the present application.

[0041] Figure 7 It is a curve diagram of the magnetic needle deflection angle and the relative value of magnetic induction intensity changing with the bending angle under the experimental condition of bending wire of the device of the present application.

[0042] In the drawings, the reference numbers of the components are as follows:

[0043] 1-angle positioning base plate, 2-current-carrying wire assembly, 3-magnetic needle measurement assembly. DETAILED DESCRIPTION

[0044] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the drawings of the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort also belong to the protection scope of the present application.

[0045] This invention simplifies and improves upon the historical experimental approach of Biot and Savart in verifying the magnetic field distribution of a current-carrying conductor using a complex periodic oscillation method. By using the Earth's magnetic field as a reference field and employing the magnetic needle deflection method for indirect measurement, the core principles of the Biot-Savart law are successfully verified in a simpler, more intuitive, and lower-cost manner. This invention not only enables intuitive verification of the Biot-Savart law in university physics experiments, improving students' understanding of electromagnetic laws and their experimental skills, but also has applications in teaching demonstrations of weak magnetic field measurement methods, geomagnetic environment determination, and the development and calibration of basic electromagnetic measurement devices. It possesses high practical value and promising prospects for widespread application.

[0046] The specific embodiments of the present invention are as follows:

[0047] Example 1

[0048] like Figure 1 As shown, this embodiment provides a demonstration experimental device for verifying the Biot-Savart law using a small magnetic needle and the Earth's magnetic field.

[0049] In terms of equipment configuration, it can be divided into three categories:

[0050] Angle positioning base plate 1: such as Figure 2 As shown, this system is used to establish an experimental reference plane and provides functions for conductor angle calibration and direction alignment, ensuring precise alignment of the conductor with the north-south direction of the Earth's magnetic field. The base plate integrates an angle scale structure, with corresponding fixing slots on each angle scale for securing the wooden rod and fixing the conductor at the corresponding bending angle. An adjustable-height bracket is located above the base plate to adjust the vertical distance between the small magnetic needle and the conductor. A level is located above the angle positioning base plate as a reference standard for determining the verticality of the base plate.

[0051] Current-carrying conductor assembly 2: such as Figure 3 As shown, the device is constructed from flexible oxygen-free copper wire, which has good conductivity and mechanical stability. It is fixed by hollow straight wooden sticks to provide stable support and precise positioning, ensuring uniform current distribution and reducing additional magnetic field interference. The device is connected to a regulated DC power supply to provide a stable and adjustable current output to the current-carrying wire, ensuring a constant current during the experiment and improving the accuracy and repeatability of the measurement.

[0052] Magnetic needle measuring component 3: such as Figure 4 As shown, a high-precision compass is selected as the core of the measurement. It has a fine scale and a reading window, which can accurately read the pointer angle. The reading accuracy of the pointer angle is 1°. It is used to sensitively indicate the direction of the magnetic field and measure the deflection angle.

[0053] In this embodiment, regarding the selection of the regulated DC power supply, the Biot-Savart law describes the basic law of magnetic field distribution caused by a current element in space. In order to accurately verify this law, the stability of the current output must be ensured during the experiment to maintain the consistency of the magnetic field in time and space, thereby improving the repeatability and controllability of the measurement results.

[0054] Based on this requirement, this embodiment uses a regulated DC power supply with a maximum output of 20V 50A to provide a constant current output, thereby creating a stable magnetic field environment. This helps to accurately observe and measure the deflection angle of the magnetic needle, ensuring the validity and reliability of the experimental data.

[0055] In this embodiment, the core measuring element of the magnetic needle measurement component is a small magnetic needle, whose performance directly affects the accuracy of deflection angle measurement and the repeatability of experimental data. To improve the sensitivity and stability of the measurement, a high-precision compass was selected. The small magnetic needle has a diameter of 35 mm and features rapid response and high sensitivity, with a measurement accuracy of up to 1°. It can effectively reflect the deflection caused by minute changes in the magnetic field, helping to obtain more reliable and consistent experimental results.

[0056] In this embodiment, high-purity oxygen-free copper was selected as the current-carrying conductor to improve the conductivity of the wire, reduce heat generation and energy loss, and ensure the stability of the current during transmission. Simultaneously, to avoid interference with experimental data due to poor contact or resistance fluctuations and to further improve experimental accuracy, the conductor was coated with a high-temperature resistant insulating enamel layer, which not only prevents short circuits but also enhances the safety and reliability of the system. The experiment requires a strong magnetic field to facilitate the measurement of the magnetic needle deflection angle, thus necessitating a sufficiently large current flow. Copper wires that are too thin are prone to overheating and melting under high current, failing to meet experimental requirements; while copper wires that are too thick, although capable of carrying a large current, are rigid and lack flexibility, hindering subsequent bending and wiring operations. Considering both conductivity and ease of operation, a 2mm diameter copper wire was chosen for the device, as it can withstand the required current while possessing good flexibility, facilitating its fabrication according to the experimental design.

[0057] In this embodiment, the fixation of the copper wire in the current-carrying conductor assembly is crucial. The appropriate selection of various structural components is essential for the accuracy of the measurement and the stability of the experiment during the setup of the experimental apparatus. To facilitate bending and shaping the copper wire while maintaining its stability, the copper wire is threaded through two hollow, straight wooden sticks with an outer length of 1000 mm, an outer radius of 10 mm, and an inner radius slightly larger than the conductor radius for auxiliary fixation. Wood itself is non-conductive and non-magnetic, facilitating operation without affecting the magnetic field distribution.

[0058] In this embodiment, to approximate the condition of an "infinitely long wire" in the theoretical model as closely as possible, the wire length was chosen to be 5000 mm to reduce the influence of edge effects on the magnetic field distribution, thereby improving the accuracy and reliability of the experiment. 2000 mm of this wire serves as the conductor generating the electromagnetic field, while the remaining portion acts as a connecting wire, achieving a good balance between performance, practicality, and theoretical consistency. Furthermore, the connecting wire is kept as perpendicular as possible to the angle positioning base plate to minimize the interference of the magnetic induction intensity generated by the current in the connecting wire on the measurement results.

[0059] In this embodiment, the angle positioning base plate is a 1200 mm × 2400 mm wooden flat plate. The plate has angle markings and corresponding fixing slots for the corresponding bending angles (15~90° in the experiment, with a step size of 7.5°), facilitating the fixing of the wire at the required bending angle. The angle positioning base plate is equipped with a level and tilt adjustment support, providing a standard for keeping the bent wire vertical in space. This design not only facilitates the measurement operation but also helps to construct an experimental scenario close to ideal conditions.

[0060] In this embodiment, for the measurement scale structure, in order to meet the requirements of fixing and observing the magnetic needle, the project adopted an adjustable height plastic bracket. Its material does not interfere with the magnetic field and can effectively avoid magnetic disturbances introduced by the metal bracket, thereby ensuring the accurate measurement of the magnetic needle deflection angle.

[0061] Device design and construction:

[0062] To avoid interference from excess wires with the magnetic field in the measurement area and to ensure that the magnetic fields they cause can cancel each other out or move away from the measurement area, first, a 5000 mm long copper wire is threaded through two 1000 mm long hollow straight wooden sticks to fix the wire, and ensure that about 8 mm of wire is left between the two hollow straight wooden sticks and that the length of the connecting wire left on both sides of the wooden sticks is roughly equal.

[0063] Observe and determine the north-south direction of the geomagnetic field using a compass, and then fix the angle positioning base plate in that direction. In practice, keep the compass firmly against the wooden board, ensuring its reading is stable at 0° or 180°, and guarantee that the angle positioning base plate is aligned with the north-south geomagnetic direction. Then, use the level and tilt adjustment device above the angle positioning base plate to adjust it to a vertical position.

[0064] In this embodiment, the midpoint of the conductor is suspended from the bending point on the angle positioning base plate, while both ends are fixed at 1000 mm from their respective angles. A compass is mounted on a plastic bracket, positioned directly above the bending point of the conductor, ensuring that the north-south direction of the compass is coplanar with the conductor. Finally, the connecting wire is straightened, its height adjusted to ensure that the plane of the connecting wire is as perpendicular as possible to the plane of the bent conductor, and then symmetrically connected to the output terminals of a regulated DC power supply to ensure a uniform and stable magnetic field and effective control of experimental conditions.

[0065] This embodiment uses the Earth's magnetic field as a reference magnetic field. Utilizing the principle of vector superposition of magnetic fields, it indirectly measures the magnetic flux density around a current-carrying conductor by measuring the deflection angle of a magnetic needle under the influence of the conductor. This replaces traditional methods relying on Hall sensors or fluxmeters, providing a measurement basis for the verification experiment of the Biot-Savart law. The device structure consists of an angle positioning base plate, a current-carrying conductor assembly, and a magnetic needle measurement assembly. Relative magnetic flux density is obtained through visualized angle readings, and data calculation is performed by combining the vector superposition relationship of magnetic fields. By measuring the relationship between the magnetic flux density on the axis of symmetry of the bent current-carrying conductor and the vertical distance, current magnitude, and bending angle, the experimental verification demonstration of the Biot-Savart law is achieved.

[0066] This device features a simple structure, high sensitivity, suitable measurement range, no need for precision measuring equipment, and low cost, effectively lowering the equipment threshold for electromagnetic experiments. Furthermore, its open-structure design facilitates multi-parameter experimental investigations, enhances teaching interactivity, and strengthens students' understanding of electromagnetic induction laws and quantitative magnetic field analysis methods. It has significant potential for widespread application in university physics experimental teaching and basic scientific research training.

[0067] Example 2

[0068] This embodiment describes the electromagnetic induction intensity measurement steps and law verification method based on the device in Embodiment 1. This system enables quantitative measurement of the magnetic field of a current-carrying conductor and experimental verification of the Biot-Savart law under geomagnetic conditions.

[0069] like Figure 5 As shown, the specific measurement steps are as follows:

[0070] 1) Measuring the magnitude of the horizontal geomagnetic field The magnetometer in the Phyphox mobile app is used to measure the magnitude of the Earth's magnetic field. The specific operation is based on the vertical horizontal plane. z The axis, the short side of the phone is x axis, with the longer side being y When measuring the horizontal component, the phone is placed on a horizontal surface, and the axis is determined by the center of the phone. z Rotate axis, record x When the axial magnetic field is 0, y Maximum value of the axis B max and minimum value B min The final value of the horizontal component The average value is obtained from multiple measurements.

[0071] 2) Adjust the specified distance r Adjust the height using the plastic bracket to ensure the vertical distance between the center of the magnetic needle and the bend point of the wire.r Adjust to the designated position and repeatedly measure to confirm accuracy.

[0072] 3) Fix a specified angle α The wire is fixed to the angle base plate at a specified angle using hollow straight wooden sticks. α Location.

[0073] 4) Adjust the specified current I Turn on the regulated DC power supply to direct the current. I Adjust precisely to the specified current.

[0074] 5) Read the initial reading Read the initial reading through the compass observation window. .

[0075] 6) Read the reading after power-on. Press the power output button and wait for the compass needle angle to stabilize before reading the compass reading while the device is powered on. Then, the power output is turned off.

[0076] 7) Take the average value , Repeat steps 5) and 6) multiple times, and take the average of the readings. , .

[0077] 8) Calculate the relative value Size: First calculate the deflection angle Then, the relative values ​​of magnetic induction intensity and geomagnetic field are obtained. .

[0078] 9) Calculate the magnetic induction intensity B c Finally, the formula is used. The magnetic flux density can then be calculated.

[0079] During the experiment, the magnetic flux density was investigated by controlling a single variable. B With current I Vertical distance r and the bending angle of the wire α The functional relationship between the three factors was investigated. In the experiment, the magnitude of the current, the distance between the magnetic needle and the bending point of the wire, and the included angle of the wire were adjusted sequentially. The deflection angle of the magnetic needle was recorded, and the corresponding magnetic induction intensity was calculated. Subsequently, the experimental data were compared and analyzed with the theoretical values ​​derived based on the Biot-Savart law.

[0080] Experimental results are as follows Figure 6 As shown, the magnetic induction intensity of a current-carrying straight conductor increases linearly with increasing current and is inversely proportional to the distance; asFigure 7 As shown, in the bent conductor configuration, the deflection angle of the magnetic needle is approximately linearly positively correlated with the bending angle. The magnetic induction intensity on the outer bisector of the current-carrying conductor angle increases with the increase of the included angle, and is related to tan( α / 2) Proportional. The experimental data of each group are highly consistent with the theoretical derivation of Biot and Savart in terms of both trend and value, indicating that the device can accurately reflect the spatial distribution law of the magnetic field of the current-carrying conductor, and has good measurement accuracy and repeatability. It can be used for teaching verification of Biot-Savart law and experimental research on weak magnetic field measurement.

[0081] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A demonstration experimental apparatus for verifying the Biot-Savart law, characterized in that, include: An angle positioning base plate is used to establish a reference measurement plane. The base plate has a direction reference line aligned with the north-south direction of the geomagnetic field, and a system for recording the bending angle of the conductor. α and the distance between the magnetic needle and the wire r The measuring scale structure; Current-carrying conductor assembly, the current-carrying conductor assembly including a section whose center forms an included angle 2 α A bendable conductor and a regulated DC power supply connected to both ends of the conductor; the plane containing the bendable conductor is perpendicular and coplanar with the direction reference line, and the regulated DC power supply is used to provide the current required for measurement. I ; A magnetic needle measuring component is provided, which is positioned at a measuring location directly above the bending point of the current-carrying conductor assembly. The magnetic needle of the magnetic needle measuring component can rotate freely around a vertical axis to indicate the direction of the magnetic field and measure the deflection angle.

2. The demonstration experimental apparatus for verifying the Biot-Savart law according to claim 1, characterized in that, The magnetic induction intensity generated by the current-carrying conductor assembly is perpendicular to the direction of the horizontal component of the geomagnetic field, causing the magnetic needle to deflect under the combined magnetic field of the geomagnetic field and the magnetic field of the current-carrying conductor.

3. The demonstration experimental apparatus for verifying the Biot-Savart law according to claim 1, characterized in that, The magnetic needle measuring component uses a high-sensitivity compass and precisely limits the vertical distance between the center of the magnetic needle and the bend point of the wire via an adjustable bracket. r。 4. The demonstration experimental apparatus for verifying the Biot-Savart law according to claim 1, characterized in that, The current-carrying conductor assembly is made of oxygen-free copper wire and is fixed by a symmetrically arranged insulating support structure, with the conductor connection extending in a direction perpendicular to the plane of the conductor.

5. A demonstration experiment method for verifying the Biot-Savart law, implemented based on the demonstration experiment apparatus for verifying the Biot-Savart law as described in any one of claims 1-4, characterized in that, Includes the following steps: 1) Read the initial direction of the magnetic needle deflection in the absence of current to obtain the direction of the horizontal component of the geomagnetic field, and fix the angle positioning base plate vertically in a direction parallel to the geomagnetic field. 2) Fix the current-carrying conductor at the corresponding bending angle. Connect the current. I This causes the current-carrying conductor to generate a magnetic field; 3) Record the deflection angle of the magnetic needle in steady state. ; 4) Calculate the magnetic induction intensity of the current-carrying conductor based on the magnetic field vector superposition relationship. B c : ； In the formula: This refers to the horizontal component of the Earth's magnetic field. This is the deflection angle of the magnetic needle.

6. The demonstration experiment method for verifying the Biot-Savart law according to claim 5, characterized in that, By changing the current I Record the deflection angle of the magnetic needle to verify the magnetic induction intensity. B c With current I A direct proportional relationship.

7. The demonstration experiment method for verifying the Biot-Savart law according to claim 5, characterized in that, By changing the distance r Record the deflection angle and verify the magnetic induction intensity. B c With distance r The inverse relationship.

8. The demonstration experiment method for verifying the Biot-Savart law according to claim 5, characterized in that, In the configuration of the bent conductor, record different included angles 2. α The deflection angle of the compass needle was verified. B c With tan( α The direct proportional relationship is 1 / 2.

9. The demonstration experiment method for verifying the Biot-Savart law according to claim 5, characterized in that, The magnetic needle and the conductor are always arranged in the same plane to ensure that the magnetic field superposition is a two-dimensional model, and the influence of the vertical component of the geomagnetic field on the deflection can be ignored, thereby improving the measurement accuracy.

10. The application of the demonstration experimental device for verifying the Biot-Savart law according to any one of claims 1-4 in university physics teaching experiments for quantitative measurement of the magnetic field distribution around a current-carrying conductor and verification of the Biot-Savart law.

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