Millikan oil drop experiment device

Abstract

The invention discloses a Millikan oil drop experiment device, and belongs to the technical field of physical experiment devices, the Millikan oil drop experiment device comprises an oil drop box, an upper pole plate, a lower pole plate, a microscopic imaging system and a voltage regulation system, the oil drop box is internally provided with an inertia separation baffle and a slit type channel limiter; the inertia separation baffle is an arc-shaped guide plate and is positioned on the inner side of the oil mist inlet of the oil drop box, and the concave surface directly faces the inlet of the observation area; the slit-type channel limiter is arranged below the inertia separation baffle and located at the top end of the inlet of the observation area, the movable sliding plate is installed in the fixed base plate in a sliding mode, and a width-adjustable limiting slit is formed between the movable sliding plate and the fixed base plate; the microscopic imaging system is used for recording an observation area and displaying output voltage; the voltage adjusting system is used for adjusting the output voltage. According to the invention, the efficiency of obtaining ideal experimental oil drops is improved, and a reliable hardware basis is provided for high-quality experimental data.

Description

Technical Field

[0001] This invention belongs to the field of physical experimental apparatus technology, specifically relating to a Millikan oil drop experiment apparatus. Background Technology

[0002] The Millikan oil drop experiment, a pivotal experiment in the history of physics for determining the fundamental electric charge, was designed and perfected by American physicist Robert Millikan in 1909. His experimental results earned him the 1923 Nobel Prize in Physics. This experiment verifies the quantization of electric charge by observing the equilibrium motion of a charged oil droplet in both electric and gravitational fields, and remains one of the essential fundamental experiments in high school and university physics education.

[0003] The traditional Millikan oil drop experiment apparatus mainly consists of an oil drop box, parallel plates, a microscopic imaging system, and a voltage regulation system. Its basic principle is to adjust the voltage between the plates to bring the charged oil droplet into equilibrium or uniform motion under the influence of gravity and electric field, thereby calculating its charge. However, in practical teaching and research applications, traditional instruments still have several technical problems that urgently need to be solved.

[0004] First, the efficiency of oil droplet generation and selection is low. Traditional devices often use manually operated press-type spray bottles (such as triangular thin-layer spray bottles) to generate oil droplets. This method produces droplets of uneven size, low atomization rate, and the large droplets easily clog the oil mist orifice, requiring frequent cleaning and severely impacting experimental efficiency. The process of manually searching for suitable objects of size and charge from a large number of random oil droplets is time-consuming, akin to "finding a needle in a haystack," becoming one of the main bottlenecks in experimental operation.

[0005] Secondly, the lack of an effective and controllable flow guidance structure for oil droplet selection means that the oil droplets become charged naturally through friction with the nozzle. Their initial velocity direction and charge magnitude distribution are random, leading to a large influx of unsuitable oil droplets (such as those that are too large, too small, or have undesirable charge) into the observation area. This not only interferes with the search for target oil droplets but also increases the error and uncertainty in data acquisition.

[0006] Therefore, how to provide a Millikan oil drop experimental apparatus that can effectively screen oil droplets before they enter the electric field region has become a problem that needs to be considered by those skilled in the art. Summary of the Invention

[0007] In view of this, the present invention provides a Millikan oil drop experiment apparatus to solve the above problems.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A Millikan oil drop experiment apparatus includes: an oil drop box, an upper electrode and a lower electrode disposed within the oil drop box, a microscopic imaging system, and a voltage regulation system. The oil drop box is equipped with an inertial separation baffle and a slit-type channel limiter. The inertial separation baffle is an arc-shaped guide plate located inside the oil mist inlet of the oil drop box, with its concave surface facing the inlet of the observation area formed by the upper and lower electrode plates. It is used to separate and guide oil droplets of different masses by utilizing the inertial differences of the oil droplets. The slit-type channel limiter is located below the inertial separation baffle and at the top of the entrance to the observation area. It includes a fixed base plate and a movable slide plate. The movable slide plate is slidably installed inside the fixed base plate and forms an adjustable-width limiting slit with the fixed base plate, which is used to perform secondary trajectory regulation on the oil droplets that pass through the inertial screening. One end of the microscopic imaging system extends into the oil droplet box to record the observation area and display the output voltage; the voltage adjustment system is electrically connected to the upper and lower electrodes to adjust the output voltage.

[0009] Furthermore, the inertial separation baffle is adjustablely installed on the inner side of the top plate of the oil drop box via an adjustment mechanism. The adjustment range of the vertical distance between the apex of the inertial separation baffle and the slit-type channel limiter is 3mm to 8mm.

[0010] Furthermore, the adjustment mechanism includes a stud and an adjustment sleeve; the adjustment sleeve is fixedly installed on the top wall of the oil drop box, the bottom end of the stud passes through the top wall of the oil drop box and the adjustment sleeve, and is fixedly connected to the inertial separation baffle; the stud is threadedly connected to the adjustment sleeve.

[0011] Furthermore, the adjustment mechanism also includes a limiting telescopic rod, the top end of which is fixedly connected to the top wall of the oil drop box, and the bottom end of which is fixedly connected to the inertial separation baffle to prevent the inertial separation baffle from rotating.

[0012] Furthermore, a flexible guide plate is connected to the bottom of the inertial separation baffle, and a conical oil collecting hopper is provided below the flexible guide plate. The conical oil collecting hopper is connected to the waste oil collection bottle outside the oil drop box via a flexible hose.

[0013] Furthermore, the movable slide plate is connected to an adjustment handle extending to the outside of the oil drop box. The adjustment handle is provided with a scale, and the side wall of the oil drop box is provided with a linear bearing corresponding to the position of the adjustment handle.

[0014] Furthermore, the oil mist inlet of the oil drop box is connected to a compressed air atomization module through an air intake pipe. The compressed air atomization module includes an air compressor and an atomizing cup connected by a pipe. A delay adjustment switch is provided on the power supply path of the air compressor.

[0015] Furthermore, the voltage regulation system is equipped with a photoelectric encoder, which is used to replace the traditional potentiometer to achieve contactless voltage regulation.

[0016] Furthermore, the width of the limiting slit is adjustable from 1.0 mm to 3.0 mm.

[0017] The beneficial effects of this invention are as follows: The inertial separation baffle designed in this invention, with its concave surface facing the oil mist inlet, effectively separates and guides oil droplets of different masses by utilizing the inertial differences of the droplets, initially filtering out excessively large or unsuitable droplets. Simultaneously, a slit-type channel limiter, composed of a fixed base plate and a movable sliding plate, forms a precisely adjustable slit to further regulate the trajectory of the oil droplets that have passed the inertial screening, ensuring that only droplets with the required direction of motion can enter the electric field observation area. This two-stage screening structure transforms the traditional time-consuming and experience-dependent manual process of finding oil droplets into a highly efficient and controllable automated screening process, significantly improving the efficiency of obtaining ideal observation droplets. This efficient and precise oil droplet screening mechanism provides stable, high-quality observation samples for subsequent electric field equilibrium measurements, reducing random errors introduced by the imperfect characteristics of the oil droplets themselves. Experimenters no longer need to expend considerable effort on a "needle-in-a-haystack" search, allowing them to focus more on understanding and measuring the physical phenomena themselves. This not only reduces operational difficulty but also makes the experimental results more stable and reliable. Furthermore, this invention has the advantages of high reliability, good durability and ease of implementation, providing powerful tool support for more accurate verification of the quantization properties of charge in teaching and scientific research. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0019] Figure 1 This is a cross-sectional view of the oil droplet box in the experimental apparatus of the present invention; Figure 2 for Figure 1 Sectional view at point AA; Figure 3 for Figure 1 Sectional view at point BB; Figure 4 This is a schematic diagram of the slit-type channel limiter structure of the present invention; Figure 5 This is a schematic diagram of the inertial separation baffle structure of the present invention; In the figure: 1-Oil drop box, 11-Oil mist inlet, 2-Upper electrode plate, 3-Lower electrode plate, 4-Microscopic imaging system, 5-Voltage regulation system, 6-Inertial separation baffle, 61-Stud, 62-Adjusting sleeve, 63-Conical oil collection hopper, 64-Flexible guide plate, 65-Waste oil collection bottle, 66-Limiting telescopic rod, 71-Fixed base plate, 72-Modible sliding plate, 73-Limiting slit, 74-Adjusting handle, 8-Air inlet pipe, 9-Atomizing cup. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Example 1

[0022] like Figure 1-5 As shown, this embodiment discloses a Millikan oil drop experiment apparatus, including an oil drop box 1, an upper electrode 2 and a lower electrode 3 disposed in the oil drop box 1, a microscopic imaging system 4, and a voltage adjustment system 5.

[0023] Specifically, the oil drop box 1 is equipped with an inertial separation baffle 6 and a slit-type channel limiter. The inertial separation baffle 6 is an arc-shaped guide plate with a specific radius of curvature (R=15mm) in its axial cross section. It is located inside the oil mist inlet 11 of the oil drop box 1. The concave surface of the inertial separation baffle 6 faces the inlet of the observation area formed by the upper electrode plate 2 and the lower electrode plate 3. It is fixed by screwing a stud 61 with an outer diameter of M8, which is rotatably connected to the center of the back of the arc-shaped guide plate, into a brass adjusting sleeve 62 with internal threads that is preset inside the top plate of the oil drop box 1. In order to achieve fine adjustment of the inertial separation baffle 6 and prevent the rotation of the inertial separation baffle 6, a limiting telescopic rod 66 is also provided at the connection between the stud 61 and the top plate of the oil drop box 1. The rotating stud 61 precisely changes the vertical distance between the inertial separation baffle 6 and the slit-type channel limiter, with an adjustment range of 3mm to 8mm. This allows for precise fine-tuning of the position of the baffle and the oil mist inlet 11. In this embodiment, the concave surface of the inertial separation baffle 6 is aligned with the axis of the oil mist inlet 11. This allows researchers to optimize the screening effect based on the initial velocity of the oil droplets and airflow conditions, improving the adaptability and operability of the equipment.

[0024] In a preferred embodiment of the present invention, a flexible guide plate 64 is fixedly connected to the bottom of the inertial separation baffle 6. The bottom of the flexible guide plate 64 is fixed, and a conical oil collecting hopper 63 is installed directly below it. The conical oil collecting hopper 63 passes through a hose through the sealed joint at the bottom of the oil drop box 1 and is led to a waste oil collecting bottle 65 outside the box. This is used to effectively collect and guide the large oil droplets and waste oil screened by the inertial separation baffle 6, prevent them from splashing or accumulating in the oil drop box 1, and keep the inside clean.

[0025] The slit-type channel limiter is located below the inertial separation baffle 6, at the top of the entrance to the observation area formed by the upper electrode plate 2 and the lower electrode plate 3. The slit-type channel limiter includes a fixed base plate 71 and a movable slide plate 72. The fixed base plate 71 is fastened to the specially designed mounting platform on the inner wall of the oil drop box 1 through the Φ3mm countersunk holes at its four corners using M3 hexagonal screws. It has a rectangular through hole with a width of 8mm in the center. The movable slide plate 72 is slidably mounted within the fixed base plate 71. By sliding and translating with the fixed base plate 71, it forms a limiting slit 73 with a gradually changing width (1.0mm to 3.0mm). The movable slide plate 72 is connected to an adjusting handle 74 extending to the outside of the oil drop box 1. The adjusting handle 74 has a scale, and a linear bearing is provided on the side wall of the oil drop box 1 corresponding to the position of the adjusting handle 74. By pulling the handle, the movable slide plate 72 can be driven to translate laterally relative to the fixed base plate 71, thereby changing the effective passage width of the limiting slit 73. The design of the scaled adjusting handle 74 and the linear bearing allows for precise and quantifiable adjustment of the slit width. The purpose is to allow the experimenter to accurately control the size of the oil droplets passing through the slit according to different experimental needs, greatly improving the accuracy and convenience of screening. A set of pre-compressed spring pins is embedded in the corresponding positioning recess on the back of the movable slide plate 72 to achieve initial positioning of the slit width. Finally, locking is achieved by tightening the star-shaped locking handwheel at the base of the handle to ensure that the movable slide plate 72 will not shift during the experiment.

[0026] It should be noted that the oil drop box 1 has holes on the outside corresponding to the position of the adjusting handle 74 and the oil collection pipe, and O-rings are used for dynamic or static sealing.

[0027] In a preferred embodiment of the present invention, the oil mist inlet 11 of the oil drop box 1 is connected to a compressed air atomization module via an air intake pipe 8. The compressed air atomization module includes an air compressor and an atomizing cup 9 connected by a pipe. A delay adjustment switch is provided on the power supply circuit of the air compressor. The high-speed compressed air flow generated by the air compressor enters the atomizing cup 9 through the air pipe, causing the oil in the cup to vibrate violently and vaporize, forming oil mist. The oil mist becomes charged by collision and friction with the inner wall of the atomizing cup, forming a large number of tiny charged oil droplets. These oil droplets are then guided into the sealed oil drop box 1 through the pipe. By precisely setting the time interval of the delay adjustment switch 93, the present invention can control the short start time of the compressor, thereby achieving precise control of the amount of oil sprayed, avoiding the obstruction of observation due to excessive oil mist in the oil drop box, or the blockage caused by excessive oil volume.

[0028] In a preferred embodiment of the present invention, the voltage regulation system 5 is electrically connected to the upper electrode plate 2 and the lower electrode plate 3 respectively. The voltage regulation system 5 is equipped with a photoelectric encoder, which replaces the traditional potentiometer. The purpose is to eliminate the wear problem of mechanical contacts, realize contactless and wear-free voltage regulation, thereby improving regulation accuracy, instrument life and operating feel. The microscopic imaging system 4 includes a CCD camera module, a light source, a display module, etc., for recording the observation area and displaying the output voltage.

[0029] The above descriptions are merely specific embodiments of the present invention, and common knowledge regarding the specific structures and characteristics of the solutions is not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

[0030] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0031] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A Millikan oil drop experiment apparatus, characterized in that, include: The oil drop box (1), the upper electrode plate (2) and the lower electrode plate (3) disposed in the oil drop box (1), the microscopic imaging system (4) and the voltage regulation system (5) are provided in the oil drop box (1). An inertial separation baffle (6) and a slit-type channel limiter are provided in the oil drop box (1). The inertial separation baffle (6) is an arc-shaped guide plate located inside the oil mist inlet (11) of the oil drop box (1). Its concave surface faces the entrance of the observation area formed by the upper electrode plate (2) and the lower electrode plate (3). It is used to separate and guide oil droplets of different masses by utilizing the inertial difference of oil droplets. The slit-type channel limiter is located below the inertial separation baffle (6) and at the top of the entrance to the observation area. It includes a fixed base plate (71) and a movable slide plate (72). The movable slide plate (72) is slidably installed inside the fixed base plate (71) and forms an adjustable-width limiting slit (73) between the fixed base plate (71) and the fixed base plate (71) for secondary trajectory regulation of oil droplets that pass through inertial screening. One end of the microscopic imaging system (4) extends into the oil drop box (1) to record the observation area and display the output voltage; the voltage regulation system (5) is electrically connected to the upper electrode plate (2) and the lower electrode plate (3) to regulate the output voltage.

2. The Millikan oil drop experiment apparatus according to claim 1, characterized in that, The inertial separation baffle (6) is adjustablely installed on the inner side of the top plate of the oil drop box (1) by an adjustment mechanism. The adjustment range of the vertical distance between the apex of the inertial separation baffle (6) and the slit channel limiter is 3mm to 8mm.

3. The Millikan oil drop experiment apparatus according to claim 2, characterized in that, The adjustment mechanism includes a stud (61) and an adjustment sleeve (62); the adjustment sleeve (62) is fixedly installed on the top wall of the oil drop box (1), the bottom end of the stud (61) passes through the top wall of the oil drop box (1) and the adjustment sleeve (62), and is fixedly connected to the inertial separation baffle (6), and the stud (61) is threadedly connected to the adjustment sleeve (62).

4. The Millikan oil drop experiment apparatus according to claim 2, characterized in that, The adjustment mechanism also includes a limiting telescopic rod (66), the top end of which is fixedly connected to the top wall of the oil drop box (1), and the bottom end of which is fixedly connected to the inertial separation baffle (6) to prevent the inertial separation baffle (6) from rotating.

5. The Millikan oil drop experiment apparatus according to claim 1, characterized in that, The bottom of the inertial separation baffle (6) is connected to a flexible guide plate (64), and a conical oil collecting hopper (63) is provided below the flexible guide plate (64). The conical oil collecting hopper (63) is connected to the waste oil collection bottle (65) outside the oil drop box (1) through a hose.

6. The Millikan oil drop experiment apparatus according to claim 1, characterized in that, The movable slide (72) is connected to an adjustment handle (74) extending to the outside of the oil drop box (1). The adjustment handle (74) is provided with a scale, and the side wall of the oil drop box (1) is provided with a linear bearing corresponding to the position of the adjustment handle (74).

7. The Millikan oil drop experiment apparatus according to claim 1, characterized in that, The oil mist inlet (11) of the oil drop box (1) is connected to the compressed air atomization module through the air intake pipe (8). The compressed air atomization module includes an air compressor and an atomizing cup (9) connected through a pipe. The power supply path of the air compressor is equipped with a delay adjustment switch.

8. The Millikan oil drop experiment apparatus according to claim 1, characterized in that, The voltage regulation system (5) is equipped with a photoelectric encoder, which is used to replace the traditional potentiometer to achieve contactless voltage regulation.

9. The Millikan oil drop experiment apparatus according to claim 1, characterized in that, The width of the limiting slit (73) is adjustable from 1.0 mm to 3.0 mm.

Images