CN113593378A

CN113593378A - Multiple probability ratio presentation device of adjustable levelness

Info

Publication number: CN113593378A
Application number: CN202110976725.4A
Authority: CN
Inventors: 高大伟; 张宁; 郑玉; 陶俊伊
Original assignee: Zhengzhou University of Light Industry
Current assignee: Zhengzhou University of Light Industry
Priority date: 2021-08-24
Filing date: 2021-08-24
Publication date: 2021-11-02

Abstract

The invention relates to a multiple probability ratio demonstration device capable of adjusting levelness, which comprises a base, wherein a circular ring is fixed at the upper end of the base, a disc which universally rotates around the gravity center of the disc but cannot rotate around the axis direction of the disc is arranged in the middle of the circular ring, a rotating shaft is inserted in the middle of the disc, a shell is arranged above the disc, a feed hopper is arranged on the shell, a plurality of through holes are formed in the disc, the shell can be fixed when positioned above any through hole, a cylindrical block is fixed in each through hole, three ball outlet holes are formed in the lower end surface of each cylindrical block, at least three ball inlet holes are formed in the upper end surface of each cylindrical block, each ball outlet hole is communicated with at least one ball inlet hole, each ball inlet hole is communicated with only one ball outlet hole, and three cylinders which rotate along with the rotating shaft are arranged under the shell; the invention ensures the randomness of demonstration by adjusting the levelness of the disc, realizes the switching of the cylindrical blocks with different probability ratios, and can demonstrate various results, and the same ball with the same specification is adopted, so that the subsequent statistics is more intuitive and is not easy to make mistakes.

Description

Multiple probability ratio presentation device of adjustable levelness

Technical Field

The invention relates to the field of mathematical teaching, in particular to a multiple probability ratio demonstration device capable of adjusting levelness.

Background

Probability, also called probability, chance rate, probability (probability) or likelihood, is the basic concept of probability theory. Probability is a measure of the probability of a random event occurring, and generally represents the magnitude of the probability of an event occurring in a real number between 0 and 1;

probability is an abstract and difficult-to-understand concept, when a student explains the concept, an expected effect is difficult to achieve, and in order to help the student understand the concept, a real object or an intuitive teaching aid is usually used for demonstrating, and further abstract knowledge is understood through actual observation;

however, for probability demonstration, the existing partial method and the existing partial method have many defects, such as: the experimental result is easily influenced by external factors such as manpower, levelness or part matching errors and the like; the demonstration mode is single, and one device can only demonstrate one result; since the counting needs to be repeated and each counting has an interval, the counting error and the like are easily caused by error recording.

Disclosure of Invention

Aiming at the situation, in order to overcome the defects of the prior art, the invention provides the demonstration device capable of adjusting the levelness and the multiple probability ratios, so that the influence of the inclination on the experimental result during probability demonstration is reduced, and the problems that the experimental result is not visual and the multiple ratios cannot be demonstrated are solved.

The demonstration device comprises a base, wherein two support rods in the vertical direction are fixed at the upper end of the base, a ring in the horizontal direction is fixedly connected at the upper ends of the two support rods, a disc is arranged in the middle of the ring, the disc can universally rotate around the center of gravity of the disc in the middle of the ring but cannot rotate around the axis direction of the disc, the disc can be kept in a horizontal state without being influenced by the levelness of the base by adjusting the relative position of the disc and the ring, and the disc can be fixed at any position;

a rotary shaft which penetrates through the upper end surface and the lower end surface of the disc and can rotate is inserted in the middle of the disc, a cylindrical shell with an opening at the lower end is arranged above the disc, the shell is fixed on the rotary shaft, a feed hopper is fixed in the middle of the upper end of the shell, a plurality of small balls with the same shape and size can be contained in the feed hopper and can enter the shell one by one, a plurality of through holes which penetrate through the upper end surface and the lower end surface are arranged on the disc, the axes of all the through holes are positioned on the moving track of the center of the opening at the lower end of the shell, the opening at the lower end of the shell can be fixed when positioned right above any through hole, a detachable cylindrical block is fixed in each through hole, three ball outlet holes are arranged on the lower end surface of the cylindrical block, at least three ball inlet holes are arranged on the upper end surface, each ball outlet hole is communicated with at least one ball inlet hole, each ball inlet hole is communicated with only one ball outlet hole, three cylinders which rotate along with the rotary shaft are arranged right below the shell, the drum is a vertically placed cylindrical shell with an opening at the upper end, and when any through hole corresponds to the opening at the lower end of the shell, the small balls discharged along the three ball discharging holes can respectively fall into the three drums.

The inner fringe face of disc outer fringe face and ring be endocentric spherical face, the disc can be universal rotatory in the ring, a cross bore that runs through the ring inside and outside has been seted up to the ring left end, the terminal surface is parallel to each other around the cross bore, there is a horizontal pole in the cross bore, the cross bore is stretched out at both ends about the horizontal pole, the horizontal pole is laminated and the last lower face interval is less than the interval from top to bottom of cross bore around the front and back of horizontal pole and cross bore, the horizontal pole right-hand member is fixed with universal ball, the logical groove of terminal surface about a running through the disc is seted up to the disc left end, the other end of universal ball is fixed in logical groove bottom, the horizontal pole can restrict the disc and rotate around self axis.

The lower end of the rotating shaft is fixed with a hemispherical rotating block, the spherical surface of the rotating block faces downwards, the spherical center of the rotating block is superposed with the spherical centers of the circular ring and the circular disc, the spherical surface of the rotating block is provided with an annular groove which takes the axis of the rotating shaft as the center of a circle, the center of the upper end of the base is rotationally connected with a rotary disc in the horizontal direction, the rotary disc can rotate around the axis of the rotary disc and can be fixed at any position, the rotary disc is fixed with a support column, the support column is rotationally connected with a worm, a slide block is arranged above the worm, the slide block is arranged in the annular groove and can slide along the annular groove, the outer end of the slide block is fixed with a rack which is radially arranged along the annular groove, the arc rack has the same radian and the same as the spherical surface of the rotating block, the worm is meshed with the rack, the outer end of the slide block is provided with an arc through groove which the center of the spherical center of the rotating block is superposed with the spherical center of the rotating block, one end of the support column is slidably connected in the through groove, and the worm can rotate by rotating block.

The base be iron material, articulated on the carousel have a pendulum rod, the free end of pendulum rod articulates has a magnet, when the pendulum rod swing to the carousel outside, magnet can adsorb and restrict the carousel and rotate on the base.

The top of pivot and the one end of worm rotate respectively and connect a hand rocker, rotate the hand rocker and can make pivot and worm rotate around the axis respectively.

The cylinder fix the up end at the turning block, every cylinder all adopts transparent material and the outer wall all is provided with scale and number of degrees, the diameter of a pellet is the unit scale.

Feeder hopper lower extreme discharge gate be fixed with the standpipe, the standpipe left side is fixed with the straight-bar of vertical direction, the casing upper end is fixed with the motor, motor shaft and straight-bar fixed connection, the motor can drive the straight-bar rotatory, be fixed with the baffle that two-layer level was placed about the straight-bar, every layer of baffle comprises 1/4 plectanes that two centrosymmetries placed and the centre of a circle and straight-bar axis coincidence, upper and lower two-layer baffle interval is a bit bigger than bobble diameter and two-layer baffle horizontal direction contained angle 90 settings, open the logical groove that has the horizontal direction in the standpipe middle part, ability shutoff standpipe lower extreme opening when lower floor's baffle rotates the standpipe position, can insert inside and cut the standpipe inner pipe way through leading to the groove when upper baffle rotates the standpipe position, the rotational speed of baffle is less than the falling speed of bobble.

The lower end of the vertical rod is provided with grooves corresponding to the number and the positions of the through holes along the circumference, the left side of the vertical rod is provided with a protruding block fixed on the disc, the protruding block is connected with a pin horizontally and arranged in a sliding mode, when the shell rotates to a position right above any one of the through holes, the pin slides rightwards and can be inserted into one of the grooves in the vertical rod to limit the vertical rod to rotate, a spring is fixed between the pin and the protruding block, and the spring enables the pin to receive pushing force sliding towards the grooves.

The through-hole be circular through-hole, the cylinder piece can the cartridge in the through-hole, cylinder piece outer fringe face is provided with the jut, and the heavy groove of vertical direction is seted up to the through-hole inner wall, the jut can restrict the cylinder piece at the through-hole internal rotation with heavy groove, the through-hole lower extreme is provided with the fender ring, plays the supporting role to the cylinder piece of placing in the through-hole.

The upper end face of the cylindrical block is provided with a plurality of funnel-shaped sinking grooves, each sinking groove corresponds to one ball inlet, all the sinking grooves are the same in size and just divide the area of the upper end face of the cylindrical block equally, and the sinking grooves can assist small balls to enter the ball inlets.

The upper end of the rotating shaft is fixed with a horizontal bubble which can display the horizontal condition of the disc, so that the levelness of the disc can be adjusted in an auxiliary mode.

The invention ensures the randomness of demonstration by adjusting the levelness of the disc, realizes the switching of the cylindrical blocks with different probability ratios, and can demonstrate various results, and the same ball with the same specification is adopted, so that the subsequent statistics is more intuitive and is not easy to make mistakes.

Drawings

Fig. 1 is a front view of the present invention.

Fig. 2 is a front sectional view of the present invention.

Fig. 3 is a partially enlarged view of a in fig. 2 according to the present invention.

Fig. 4 is a top cross-sectional view a-a of fig. 1 of the present invention.

FIG. 5 is a top cross-sectional view B-B of FIG. 1 in accordance with the present invention.

FIG. 6 is a perspective view of a cylindrical block with three ball inlet holes according to the present invention.

Fig. 7 is a sectional perspective view of the internal structure of a cylindrical block having four ball inlet holes according to the present invention.

Fig. 8 is a sectional perspective view of the inner structure of a cylindrical block having five ball inlet holes according to the present invention.

FIG. 9 is a perspective view of the shaft, disk, through-hole, turning block and annular groove of the present invention.

Detailed Description

The following description of the embodiments of the present invention will be made in detail with reference to the accompanying drawings.

As shown in fig. 1 to 9, the present invention includes a base 1, two support rods 3 in a vertical direction are fixed at the upper end of the base 1, a ring 2 in a horizontal direction is fixedly connected at the upper end of each support rod 3, a disc 16 is arranged in the middle of the ring 2, the disc 16 can rotate around the center of gravity of the disc 2 in a universal manner but cannot rotate around the axis direction of the disc, the disc 16 can be kept in a horizontal state without being affected by the levelness of the base 1 by adjusting the relative positions of the disc 16 and the ring 2, and the disc 16 can be fixed at any position;

a rotating shaft 4 which penetrates through the upper end face and the lower end face of a disc 16 and can rotate is inserted in the middle of the disc 16, a cylindrical shell 11 with an opening at the lower end is arranged above the disc 16, the shell 11 is fixed on the rotating shaft 4, a feed hopper 14 is fixed in the middle of the upper end of the shell 11, a plurality of small balls 13 with the same shape and size can be placed in the feed hopper 14 and can enter the shell 11 one by one, a plurality of through holes 18 which penetrate through the upper end face and the lower end face are formed in the disc 16, the axes of all the through holes 18 are positioned on the moving track of the center of the opening at the lower end of the shell 11, the opening at the lower end of the shell 11 can be fixed when being positioned right above any through hole 18, a detachable cylindrical block 17 is fixed in each through hole 18, three ball outlet holes 31 are formed in the lower end face of the cylindrical block 17, the upper end face is provided with at least three ball inlet holes 30, each ball outlet hole 31 is communicated with at least one ball inlet hole 30, and each ball inlet hole 30 is communicated with only one ball outlet hole 31, three cylinders 10 rotating along with the rotating shaft 4 are arranged right below the shell 11, the cylinders 10 are vertically arranged and are cylindrical shells with openings at the upper ends, and when any through hole 18 corresponds to an opening at the lower end of the shell 11, the small balls 13 discharged along the three ball discharging holes 31 can respectively fall into the three cylinders 10.

16 outer fringe face of disc and ring 2's interior fringe face be concentric spherical face, disc 16 can be universal rotation in

ring

2, 2 left ends of ring have been seted up one and have been run through the inside and outside cross bore 27 of ring 2, the terminal surface is parallel to each other around the cross bore 27, there is a horizontal pole 28 in the cross bore 27, cross bore 27 is stretched out at both ends about horizontal pole 28, horizontal pole 28 is laminated and the last lower surface interval is less than the interval of cross bore 27 from top to bottom around the front and back of horizontal pole 28 and the laminating of cross bore 27, horizontal pole 28 rightmost end is fixed with universal ball 29, disc 16 left end sets up a logical groove that runs through terminal surface about disc 16, the other end of universal ball 29 is fixed in logical groove bottom, logical groove can give the horizontal pole 28 that reciprocates and give the position, horizontal pole 28 can restrict disc 16 around self axis rotation.

A hemispherical rotating block 6 is fixed at the lower end of the rotating shaft 4, the spherical surface of the rotating block 6 faces downwards, the spherical center of the rotating block 6 is coincided with the spherical centers of the circular ring 2 and the circular disc 16, an annular groove 24 which takes the axis of the rotating shaft 4 as the center of a circle is arranged on the spherical surface of the rotating block 6, a turntable 7 in the horizontal direction is rotatably connected at the upper end center of the base 1, the turntable 7 can rotate around the axis of the turntable 7 and can be fixed at any position, a support column is fixed on the turntable 7, a worm 8 is rotatably connected on the support column, a sliding block 9 is arranged above the worm 8, the sliding block 9 is arranged in the annular groove 24 and can slide along the annular groove 24, a rack 26 which is arranged along the radial direction of the annular groove 24 is fixed at the outer end of the sliding block 9, the rack 26 is an arc rack, the radian and the center of the arc are the same as the spherical surface of the rotating block 6, the worm 8 is meshed with the rack 26, an arc through groove which the center of the circle is coincided with the spherical center of the rotating block 6 is arranged at the outer end of the sliding block 9, one end of the support column is connected in the through groove in a sliding way, the worm 8 can be rotated to drive the rotating block 6 to rotate around the sphere center by the sliding block 9.

The base 1 be iron material, articulated on the carousel 7 have a pendulum rod 22, the free end of pendulum rod 22 is articulated to have a magnet 23, when pendulum rod 22 swung the carousel 7 outside, magnet 23 can adsorb and restrict carousel 7 and rotate on the base 1.

The top of pivot 4 and the one end of worm 8 rotate respectively and connect a hand rocker, rotate the hand rocker and can make pivot 4 and worm 8 rotate around the axis respectively.

The cylinders 10 are fixed on the upper end face of the rotating block 6, each cylinder 10 is made of transparent materials, scales and degrees are arranged on the outer wall of each cylinder, and the diameter of one small ball 16 is a unit scale.

14 lower extreme discharge gate of feeder hopper be fixed with standpipe 25, standpipe 25 left side is fixed with straight-bar 19 of vertical direction, 11 upper ends of casing are fixed with motor 15, motor 15 pivot and straight-bar 19 fixed connection, motor 15 can drive the rotation of straight-bar 19, be fixed with baffle 20 that two-layer level was placed about on the straight-bar 19, every layer of baffle 20 comprises two central symmetry places and the 1/4 plectanes of centre of a circle and the coincidence of straight-bar 19 axis, two-layer baffle 20 interval is slightly greater than 13 diameters of bobble and two-layer baffle 20 horizontal direction contained angle 90 settings about, open the logical groove that has the horizontal direction in standpipe 25 middle part of standpipe 25, can shutoff standpipe 25 lower extreme opening when lower floor's baffle 20 rotates to standpipe 25 positions, can insert inside shutoff standpipe 25 inside pipeline of standpipe 25 through leading to the groove when upper baffle 20 rotates to standpipe 25 positions, the rotational speed of baffle 20 is less than the falling speed of bobble 13.

The lower end of the vertical rod 20 is circumferentially provided with grooves corresponding to the number and the positions of the through holes 18, the left side of the vertical rod 20 is provided with a protruding block 12 fixed on the disc 16, the protruding block 12 is connected with a horizontally arranged pin 21 in a sliding manner, when the shell 11 rotates to a position right above any one of the through holes 18, the pin 21 slides rightwards and can be inserted into one of the grooves on the vertical rod 20 to limit the rotation of the vertical rod 20, a spring is fixed between the pin 21 and the protruding block 12, and the spring enables the pin 21 to be pushed by sliding force towards the grooves.

The through hole 18 is a circular through hole, the cylindrical block 17 can be inserted into the through hole 18, the outer edge surface of the cylindrical block 17 is provided with a protruding block, the inner wall of the through hole 18 is provided with a sinking groove in the vertical direction, the protruding block and the sinking groove can limit the cylindrical block 17 to rotate in the through hole 18, the lower end of the through hole 18 is provided with a retaining ring which plays a supporting role for the cylindrical block 17 arranged in the through hole 18.

The upper end face of the cylindrical block 17 is provided with a plurality of funnel-shaped sinking grooves, each sinking groove corresponds to one ball inlet hole 30, the sinking grooves are the same in size and just divide the area of the upper end face of the cylindrical block 17 equally, and the sinking grooves can assist the small balls 16 to enter the ball inlet holes 30.

The upper end of the rotating shaft 4 is fixed with a horizontal bubble 5, and the horizontal bubble 5 can display the horizontal condition of the disc 16, so that the levelness of the disc 16 can be adjusted in an auxiliary manner.

It should be noted that the number of the ball outlet holes 31 determines the number of groups, the number of the ball inlet holes 30 communicated with each ball outlet hole 31 determines the size of the group, and the ball inlet holes 30 and the ball outlet holes 31 have theoretically infinite combinations according to the above-mentioned communication manner that each ball outlet hole 31 is communicated with at least one ball inlet hole 30 and each ball inlet hole 30 is communicated with only one ball outlet hole 31, so that the cylindrical blocks 17 with infinite probability ratios can complete the demonstration in the device, for example, the combination selected in the present scheme:

when the number of the ball inlet holes 30 on the cylindrical block 17 is different, as shown in fig. 6, 7 and 8, the numbers are respectively 1: 1: 1. 1: 1: 2 and 1: 2: 2;

when the number of the ball inlet holes 30 on the cylindrical block 3 is the same, the ball inlet holes 30 and the ball outlet holes 31 may have different communication modes, for example, as shown in fig. 8, which may be adjusted to 1: 2: 2 and 1: 1: 3;

when the number of the ball inlet holes 30 on the cylindrical block 17 is the same and the probability ratio of the verification is the same, the communication order of the ball inlet holes 30 can also be adjusted, for example, according to 1 in fig. 8: 2: 2, the ball inlets 30 in the two-in-one set may be arranged in a series, or may be arranged in a series at intervals, or the ball inlets 30 in the two-in-one set may be connected to the leftmost ball outlet 31 or the rightmost ball outlet 31.

In the present invention, the number of the ball outlet holes 31 is set to three, the corresponding demonstration result is a probability ratio of three groups of numbers, and the number of the probability ratio groups can be any number, so that the number of the ball outlet holes 31 can be set to any number and is not limited to three as mentioned in the present invention.

Before the invention is used, the cylindrical blocks 17 with different probability ratios are arranged in the through holes 18 on the disc 16, the cylindrical block 17 corresponding to the probability ratio to be demonstrated is selected, the rotating shaft 4 is rotated through the hand lever on the rotating shaft 4, the shell 11 and the cylinder 10 are rotated to the direction opposite to the cylindrical block 17, the three ball outlet holes 31 are respectively in one-to-one correspondence with the three cylinders 10, the pins 21 are arranged in the grooves on the rotating shaft 4, and the pins 21 can be always arranged in the grooves under the thrust of the spring to prevent the rotating shaft 4 from rotating;

then observing whether the bubbles on the horizontal bubble 5 are positioned in the middle, when the bubbles are positioned in the middle, indicating that the disc 16 is horizontally placed, when the bubbles are not positioned in the middle, rotating the turntable 7, when the central axis of the worm 8 on the turntable 7 is consistent with the offset direction of the bubbles, stopping rotating the turntable 7, contacting the magnet 23 with the base 1, so that the turntable 7 cannot rotate, then rotating the worm 8 through a hand lever, wherein the worm 8 drives the slider 9 to ascend or descend along the arc-shaped through groove through the rack 26, the slider 9 moves to drive the rotating block 6 to rotate around the sphere center, the rotating block 6 drives the disc 16 to rotate inside the circular ring 2 through the rotating shaft 4, meanwhile, the rotating shaft 4 swings to enable the bubbles on the horizontal bubble 5 to move towards the middle, and when the bubbles move to the middle, stopping rotating the worm 8, and at the moment, the disc 16 is horizontally placed;

when the invention is used, a plurality of small balls 13 with certain elasticity are placed in the feed hopper 14, the motor 15 is started at the same time, the motor 15 drives the baffle 20 to rotate through the straight rod 19, when the lower baffle 20 releases one small ball 13, the upper baffle 20 can block the falling of the upper small ball 13 once until the lower end of the vertical pipe 25 is sealed by the lower baffle 20, the upper baffle 20 releases the small balls 13, the circulation enables the small balls 13 to fall one by one, the falling small balls can only fall downwards from the middle part because the device is in a horizontal state, after the small balls fall onto the cylindrical block 17, because the upper end circumference of the cylindrical block 17 is uniformly provided with the sinking grooves, the probability of falling into any sinking groove of the cylindrical block 17 is the same, the small balls enter the corresponding ball inlet 30 along the sinking grooves and then are discharged into the cylinder 10 below the ball outlet 31 through the ball outlet 31, when all the small balls enter the cylinder 10 at the lower side, the motor 5 is turned off and the numbers corresponding to the uppermost pellet in the three cylinders 10 are noted, the numbers representing the number of pellets, and the counted numbers are compared with the imaginary ratio.

According to the invention, each ball outlet hole 31 is at least communicated with one ball inlet hole 30, and each ball inlet hole 30 is only communicated with one ball outlet hole 31, so that the theoretical probability of experimental demonstration is ensured to be established;

the cylindrical blocks 17 with different probability ratio structures fixed on the disc 16 can respectively correspond to the shell 1 and the cylinder 10 by rotating the disc 16, so that the different probability ratio demonstration can be rapidly switched, a set of device can perform demonstration experiments on various probability ratios, and the interestingness of the experiments is increased;

the three cylinders 10 for collecting the small balls 13 are made of transparent materials, and the outer walls of the three cylinders are provided with scales and degrees, so that the observation is more visual, the small balls 13 are in the same color and the same size, so that the small balls do not need to be distinguished in each recording, the error of probability is reduced, and the statistics is more convenient and quicker;

according to the invention, the disc 16 and the ring 3 are matched through a spherical surface, so that the disc 16 can rotate universally, structural support is provided for adjusting the parallelism of the disc 16, the slider 9 can slide in the annular groove 24, and the height of the slider 9 can be adjusted by meshing the worm 8 with the rack 26 on the slider 9, so that the slider 9 can adjust the deflection height of the rotating block 6 from any position on the annular groove 24, the adjustment of the levelness of the disc 16 is realized, and the influence of the levelness on the falling position of the small ball 13 is avoided, thereby influencing the experimental randomness;

the matching of the cross rod 28 and the cross hole 27 ensures that the disc 16 cannot rotate along the axial direction, ensures that the rotation of the rotating shaft 4 is the only variable in the corresponding situation of the adjusting shell 11 and the through hole 18, and reduces the adjusting difficulty and the adjusting error;

through 20 interval arrangements of upper and lower two-layer baffle and horizontal direction contained angle 90, make the bobble 13 in the standpipe 25 fall one after 19 every rotatory half circles of straight-bar, guarantee falling one by one of bobble, avoid the mutual interference influence experimental result between the back bobble of whereabouts simultaneously, make the randomness of experiment more persuasive.

Claims

1. A multiple probability ratio demonstration device capable of adjusting levelness is characterized by comprising a base (1), wherein two support rods (3) in the vertical direction are fixed at the upper end of the base (1), the upper ends of the two support rods (3) are fixedly connected with a ring (2) in the horizontal direction, a disc (16) is arranged in the middle of the ring (2), the disc (16) can rotate around the gravity center of the disc (2) in a universal mode but cannot rotate around the axis direction of the disc, the disc (16) can be kept in a horizontal state without being influenced by the levelness of the base (1) by adjusting the relative position of the disc (16) and the ring (2), and the disc (16) can be fixed at any position;

a rotating shaft (4) which penetrates through the upper end face and the lower end face of the disc (16) and can rotate is inserted in the middle of the disc (16), a cylindrical shell (11) with an opening at the lower end is arranged above the disc (16), the shell (11) is fixed on the rotating shaft (4), a feed hopper (14) is fixed in the middle of the upper end of the shell (11), a plurality of small balls (13) with completely the same shape and size can be placed in the feed hopper (14), the small balls (13) can enter the shell (11) one by one through the feed hopper (14), a plurality of through holes (18) which penetrate through the upper end face and the lower end face are formed in the disc (16), the axes of all the through holes (18) are positioned on the moving track of the center of the opening at the lower end of the shell (11), the opening at the lower end of the shell (11) can be fixed when positioned right above any through hole (18), a detachable cylindrical block (17) is fixed in each through hole (18), three ball outlet holes (31) are formed in the lower end face of the cylindrical block (17), the upper end face is opened and is had quantity to be no less than three goal hole (30), every ball hole (31) communicate with one goal hole (30) at least and every goal hole (30) only with one play ball hole (31) intercommunication, position has three drum (10) along with pivot (4) rotation under casing (11), drum (10) are vertical place and upper end open-ended cylinder casing, when arbitrary through-hole (18) and casing (11) lower extreme opening correspond, can drop respectively in three drum (10) along three little ball (13) of ball hole (31) discharge.

2. The demonstration device for multiple probability ratios with adjustable levelness according to claim 1, wherein the outer edge surface of the disc (16) and the inner edge surface of the ring (2) are concentric spherical surfaces, the disc (16) can universally rotate in the ring (2), the left end of the ring (2) is provided with a transverse hole (27) penetrating through the inside and outside of the ring (2), the front end surface and the rear end surface of the transverse hole (27) are parallel to each other, a transverse rod (28) is arranged in the transverse hole (27), the left end and the right end of the transverse rod (28) extend out of the transverse hole (27), the front end and the rear end surface of the transverse rod (28) are attached to the front end and the rear end surface of the transverse hole (27), the distance between the upper surface and the lower surface of the transverse hole (27) is smaller than that between the upper surface and the lower surface of the transverse hole (27), the rightmost end of the transverse rod (28) is fixed with a universal ball (29), the left end of the disc (16) is provided with a through groove penetrating through the upper end and the lower end surface of the universal ball (29), and the other end of the universal ball is fixed at the bottom of the through groove, the cross bar (28) can limit the disc (16) to rotate around the axis thereof.

3. The demonstration device for multiple probability ratios capable of adjusting levelness according to claim 2, wherein a hemispherical rotating block (6) is fixed at the lower end of the rotating shaft (4), the spherical surface of the rotating block (6) faces downwards, the spherical center of the rotating block (6) coincides with the spherical centers of the circular ring (2) and the circular disc (16), an annular groove (24) taking the axis of the rotating shaft (4) as the center of circle is formed in the spherical surface of the rotating block (6), a horizontal rotating disc (7) is rotatably connected to the center of the upper end of the base (1), the rotating disc (7) can rotate around the axis of the rotating disc and can be fixed at any position, a supporting column is fixed on the rotating disc (7), a worm (8) is rotatably connected to the supporting column, a sliding block (9) is arranged above the worm (8), the sliding block (9) is arranged in the annular groove (24) and can slide along the annular groove (24), and a rack (26) arranged along the radial direction of the annular groove (24) is fixed at the outer end of the sliding block (9), the rack (26) is an arc rack, the radian and the circle center of the arc rack are equal to those of the spherical surface of the rotating block (6), the worm (8) is meshed with the rack (26), the outer end of the sliding block (9) is provided with an arc through groove with the circle center coinciding with the sphere center of the rotating block (6), one end of the supporting column is connected in the through groove in a sliding mode, and the sliding block (9) can be driven to rotate around the sphere center by rotating the worm (8).

4. The demonstration device for multiple probability ratios capable of adjusting levelness according to claim 3, wherein the base (1) is made of iron, the rotary disc (7) is hinged with a swing rod (22), the free end of the swing rod (22) is hinged with a magnet (23), and when the swing rod (22) swings to the outer side of the rotary disc (7), the magnet (23) can be adsorbed on the base (1) to limit the rotation of the rotary disc (7).

5. The demonstration device for multiple probability ratios with adjustable levelness as claimed in claim 3, wherein the uppermost end of the rotating shaft (4) and one end of the worm (8) are respectively connected with a hand lever in a rotating manner, and the rotating hand lever can respectively rotate the rotating shaft (4) and the worm (8) around the axis.

6. The demonstration device for multiple probability ratios capable of adjusting levelness according to claim 3, wherein the cylinders (10) are fixed on the upper end surface of the rotating block (6), each cylinder (10) is made of transparent materials, scales and degrees are arranged on the outer wall of each cylinder, and the diameter of one small ball (16) is a unit scale.

7. The device for demonstrating multiple probability ratios with adjustable levelness according to claim 1, wherein a vertical tube (25) is fixed at a discharge port at the lower end of the feed hopper (14), a vertical rod (19) in the vertical direction is fixed on the left side of the vertical tube (25), a motor (15) is fixed at the upper end of the housing (11), a rotating shaft of the motor (15) is fixedly connected with the vertical rod (19), the motor (15) can drive the vertical rod (19) to rotate, an upper layer and a lower layer of horizontally arranged baffles (20) are fixed on the vertical rod (19), each layer of baffles (20) is composed of 1/4 circular plates which are symmetrically arranged in the center and the centers of which coincide with the axis of the vertical rod (19), the interval between the upper layer of baffles (20) and the lower layer of baffles is slightly larger than the diameter of the small ball (13), and the included angle of 90 degrees in the horizontal direction of the two layers of baffles (20) is arranged, a horizontal through groove is formed in the middle of the vertical tube (25), and the lower end opening of the vertical tube (25) can be blocked when the lower baffles (20) rotates to the position of the vertical tube (25), when the upper baffle (20) rotates to the position of the vertical pipe (25), the upper baffle can be inserted into the vertical pipe (25) through the through groove and cut off the pipeline inside the vertical pipe (25), and the rotating speed of the baffle (20) is less than the falling speed of the small balls (13).

8. The device for demonstrating multiple probability ratios of levelness adjustable according to claim 1, wherein the lower end of the vertical rod (20) is circumferentially provided with grooves corresponding to the number and the positions of the through holes (18), the left side of the vertical rod (20) is provided with a protruding block (12) fixed on the disc (16), the protruding block (12) is slidably connected with a horizontally arranged pin (21), when the housing (11) rotates to a position right above any one of the through holes (18), the pin (21) slides rightwards and can be inserted into one of the grooves on the vertical rod (20) to limit the rotation of the vertical rod (20), a spring is fixed between the pin (21) and the protruding block (12), and the spring enables the pin (21) to be pushed by sliding towards the grooves.

9. The device for demonstrating multiple probability ratios of adjustable levelness as claimed in claim 1, wherein said through hole (18) is a circular through hole, the cylindrical block (17) can be inserted into the through hole (18), the outer edge surface of the cylindrical block (17) is provided with a protrusion, the inner wall of the through hole (18) is provided with a vertical sinking groove, the protrusion and the sinking groove can limit the cylindrical block (17) to rotate in the through hole (18), the lower end of the through hole (18) is provided with a retaining ring, and the retaining ring can support the cylindrical block (17) in the through hole (18).

10. The demonstration device for multiple probability ratios with adjustable levelness as claimed in claim 1, wherein the upper end surface of the cylindrical block (17) is provided with a plurality of funnel-shaped sinking grooves, each sinking groove corresponds to one ball inlet hole (30), and all sinking grooves have the same size and just equally divide the area of the upper end surface of the cylindrical block (17).