CN2919415Y

CN2919415Y - Coulomb's law demonstration instrument

Info

Publication number: CN2919415Y
Application number: CN 200420014387
Authority: CN
Inventors: 李建民
Original assignee: Individual
Current assignee: Individual
Priority date: 2004-10-21
Filing date: 2004-10-21
Publication date: 2007-07-04
Anticipated expiration: 2014-10-21

Abstract

The utility model relates to a teaching instrument used for validating the Coulomb law in physical teaching. The utility model is on the basis of two electrified balls served as a simulated point charges. The designed demonstrating box is provided with a special-purpose gauge head. The gauge head is provided with a gravity center adjusting device. A pendulum pillar is connected with a pendulum rod and a pendulum ball at the bottom. The gauge head is provided with a zero resetting device because the error can produce after the pendulum ball swings for a plurality of times during the experiment. A demonstrating board is provided with a sliding groove joint. The sliding groove joint is provided with an L-shaped rod with a mobile ball. The mobile ball can move back or forth, right or left, high or lower in order to follow the level position of the pendulum ball manipulated outside the demonstrating box. The utility model solves the Coulomb force measurement problem. Two electrified balls are surface-glazed metal-membrane equally-sized balls.

Description

The Coulomb law demonstrator

Technical field: the utility model relates to physics teaching, a kind of instruments used for education of demonstration and verification Coulomb law.

Technical background: at present, in the physics teaching, the experimental demonstration method of relevant Coulomb law, many instruments all can only observe phenomena, even if design best instruments used for education, also can only measure the spacing r of simulation points electric charge, and the Coulomb force F between the simulation points electric charge, can only change by the angle of spheroid swing at the most, the approximate ratio that must exert oneself, and error is very big, can't directly measure the magnitude numerical value of power, therefore to the education experiment of Coulomb law, only possesses the verification condition of part.

Summary of the invention: demonstrate all relevant instruments used for education in order to overcome in the existing physics teaching Coulomb law, can not solve the problem of checking fundamental physical quantity fully.The utility model provides a kind of Coulomb law demonstrator, not only can solve long charged problem, and can observe two simulation points electric charge positions by demonstration board, measure their mutual spacings, micro-force measurement meter by the specialized designs making, the sizes values of Coulomb force calculates total electric weight Q according to formula when measuring a simulation points electric charge and departing from the equilibrium position arbitrarily ₁Q ₂Value.

The utility model solves its technical matters, the technical scheme that is adopted is: external form is about 45 centimetres of height and width, thick about 15 centimetres square demonstration casing, be divided into two parts up and down with dividing plate, dividing plate fluting seam, adjustable special-purpose gauge outfit is installed above, stretches out fork downwards, hang swing ball below the fork from line of rabbet joint mouth.Demonstration board below the dividing plate, the corresponding position, upright position with swing ball when static indicates zero graduation, turns left along the camber line that draws on the camber line, and the parallel lines that draw of turning right indicate below apart from groove the angle of drawing on the camber line on zero graduation left side groove.Near right panel, demonstration board scale mark upper edge, beginning continues fluting along the camber line top behind the zero passage scale mark, till near the left margin toward the parallel fluting in the left side; Pass the chute seam with the insulated hollow bolt in the demonstration box, the outside screws with the insulation nut, is fixed on the chute; One end of L type insulation strut is loaded onto mobile bead, the other end is inserted in the insulated hollow bolt hole and passes, suitably expose the termination, move the insulation nut with hand in the demonstration board back, about bead is done along the chute track, up and down and move horizontally, turn nut and the termination of suitably twitching pole, can regulate mobile bead about and front and back position.The installation of gauge outfit is achieved in that around the line of rabbet joint above the dividing plate; The groove box of a built-in magnetic stripe of frame is installed, and an end of groove box is opened circular hole, and slotted hole is opened on the two sides, front and back, and iron plate is posted in gauge outfit annulus top and the bottom, when making it put into the groove box, can be adsorbed on the magnetic stripe; At the aperture place that annulus is left, pass an elongated screw rod and fixing, from groove box circular hole, pass, the hole is changeed in relevant position at demonstration box, and a joint stop sleeve is installed, and stretches a nearly nut bar and screw rod and is nested, on the nut bar snap ring is installed, in case nut bar move left and right has only the rotation of regulating knob by the outside, annulus is produced in the groove box move horizontally; Gauge outfit annulus two ends are embedded with the jewel screw, and set screw will be put post and is fixed in the jewel screw, and pendulum post top is by the gravity balance screw rod, and center of gravity is regulated nut and formed the gravity balance device; Pendulum post below is by fork, and swing ball is formed the gauge outfit swing part jointly, the turn center of gravity is regulated nut, can change the center of gravity of oscillation system, oscillation system can be worked under microgravity condition, when the microgravity effect that is subjected to horizontal direction just can produce tangible swing deflection; In order to make swing ball can effectively keep the quantity of electric charge, adopt the Metallic rod part below the pendulum post, peg graft or suit one pipe nipple insulating bar, the thinner bar of metal tightly is inserted in the insulated column, the lower end connects and is inserted with the insulate swing ball of thin bar of cutting back.Measuring the deflection force of swing ball, is to be finished by the micro-force measurement meter of special making.Before the experiment, promote swing ball to a certain angle from horizontal direction, read the value of a power with the micro-force measurement meter, thus, can reasoning, during like charges, the size of its power should be equal to the value of micro-force measurement meter in this place dynamometry on two zona glomerulosas.Because swing ball is subjected to coulomb repulsion power from mobile bead all the time, the Coulomb force can be expressed as: F=mgtg θ, and mg is constant, so F can come ratio with tg θ, for convenience of calculation, measure the horizontal repulsive force F of special angle tg θ=45 when spending.Under the interior unspecified angle of measurement range, the coulomb repulsion power F '=F*tg θ ' that is subjected to is exactly the value of this Coulomb force so.The manufacturing process of micro-force measurement meter: with an elongated rotating shaft, insert the uniform rigid foam film of thickness disc centre, insert rigid foam film disk edge with lightweight filament bar, exposed portions serve is made the circular arc type dynamometer link, one end of foam discs central rotating shaft overlaps a hairspring; Get a cylinder, on the arc surface of cylinder middle part, open a groove, the hairspring fixed mount of mounting strap latch on the dome, the jewel screw of two domes is up and down put in rotating shaft, built dome, mix up the degree of tightness of jewel screw, make dynamometer link be exposed at the outer end of notch, as zero position.Dynamometer link gently being pushed the line of rabbet joint mouth other end, be in the maximal value of elastic force, is the measurement range of this meter.Mark after the equidistant scale division value, just finish making.During use, promote swing ball with the dynamometer link level, it is stressed all the time on dynamometer circular arc tangential line direction, just can measure the stressing conditions of swing ball.Be transparent portable plate below the demonstration box, its structure is that top panel extends a certain height below the dividing plate, and corresponding the narrowing down of both sides side panel under the dividing plate loaded onto magnetic sheet.The transparent panel edge is equipped with iron plate, and it is sticked on the magnetic frame that is adsorbed on side panel.Above align with the bottom of panel just.Because the side panel below panel and the dividing plate leaves the sealing of certain width, can make transparent panel pass through manually up to move to partition position, the space that makes the bottom expose certain altitude.Utilize the bottom space operation experiments, make swing ball, mobile bead is charged, and in order to prevent external interference: become big as wind and humidity, the transparent portable plate that can move down makes its sealing; On the demonstration board of the demonstration box lower left corner, lighting bulb is installed, is used for illumination and baking and removes tide; Shading treatment is carried out in the relevant position in transparent panel left side, and alleviating stimulates for a long time to human eye.

Description of drawings:

Fig. 1 is the schematic appearance of Coulomb law demonstration instrument.

Fig. 2 is the hollow bolt front view (FV) of pegging graft mobile bead L type pole.

Fig. 3 is the hollow bolt outboard profile of pegging graft mobile bead L type pole.

Fig. 4 is mobile bead and the sectional view of stationary installation on demonstration board.

Fig. 5 is special-purpose gauge outfit of Coulomb law demonstration instrument and balancing controls Facad structure figure.

Fig. 6 is the vertical view of special-purpose gauge outfit and balancing controls.

Fig. 7 is in the special table head unit, gauge outfit groove box left view.

Fig. 8 is the micro-force measurement meter outside drawing of test swing ball deflection force.

Fig. 9 is the foam rotating-table apparatus vertical view in the micro-force measurement meter.

Figure 10 is the side-looking diagrammatic cross-section in the micro-force measurement meter.

Figure 11 is the left view of Coulomb law demonstration box.

Figure 12 is a Coulomb law demonstrator demonstration board structural representation.

Figure 13 is special-purpose gauge outfit oscillation system modular construction figure.

Figure 14 is gauge outfit annulus frame and pendulous device vertical view.

Figure 15 is a gauge outfit annulus front schematic view.

Figure 16 is the left view of gauge outfit annulus in the groove box.

Figure 17 is a gauge outfit groove box front schematic view.

Figure 18 is a gauge outfit groove box vertical view.

Figure 19 is the movable transparent panel of demonstration box.

Figure 20 is experimental principle figure.

Among the figure: 1. the demonstration casing, 2. the gauge outfit fork, 3. zero-bit is regulated knob, 4. gauge outfit groove box, 5. dividing plate, 6. groove.7. lighting bulb, 8. insulated hollow bolt, 9. insulated hollow nut, 10.L type insulation strut, 11. chute seam, 12. mobile bead, 13. the gauge outfit center of gravity is regulated nut, 14. gauge outfit gravity balance screw rod, 15. magnetic stripe in the groove box, 16. gauge outfit moves annulus, 17. zeroing screw rod, 18. zeroing nut bar, 19. insulated bolt hollow hole, 20. demonstration box side panel, 21. groove box circular hole, 22. micro-force measurement meter top cover, 23. dynamometry indicates scale mark, 24. dynamometry screw mandrel, 25. arc line of rabbet joint mouth, 26. foam discs, 27. clock and watch hairspring, 28. rotating shaft, 29. spiral head gim peg, 30. shading surface, 31. transparent area cover plate, 32. stripe shape iron plate, 33. magnetic stripe, 34. deflection angle groove, 35. apart from groove, 36. demonstration board, 37. pendulum post, 38. swing ball, 39. jewel screw, 40. fork insulated part, 41. iron plate, 42. fork insulated part, 43. the dividing plate line of rabbet joint, 44. groove box cylindrical void, 45. nut bar snap ring, 46. annulus screw.

Specific implementation method: in Fig. 1, swing ball (38) and mobile bead (12) are if all be with like charges, and swing ball will stressedly depart from zero-bit and form certain drift angle and distance.Because spacing is bigger, can regard two beads as point charge Q ₁Q ₂, simultaneously, two beads etc. are big, and surface area is identical, when being with full phase with electric charge, Q ₁=Q ₂By F=K Q ₁Q ₂/ r ², as can be known, when the value F that measures apart from r and power, just can calculate electric weight Q ₁Q ₂, because the quantity of electric charge of two beads is equal, so can calculate Q ₁And Q ₂Value.The short-cut method of test force, can promote swing ball to 45 ° drift angle by the micro-force measurement meter, observe the stressed in the horizontal direction situation of swing ball this moment, record data, because the stressed F=mgtg θ of swing ball horizontal direction, and the suffered gravity mg of swing ball is a constant, and thus, the stressed ratio of swing ball is F=tg θ, so in the measurement range, the arbitrarily angled power that is subjected to from horizontal direction of swing ball is F: F '=tg45 °: tg θ ', so, F '=Ftg θ '.And in experimentation, swing ball and mobile bead are in same level height all the time, and what swing ball was subjected to is the coulomb repulsion power of horizontal direction, principle according to this, the value of the Coulomb force in the time of can measuring different drift angle.Fig. 2 and Fig. 3 are the insulated hollow bolts, its installation method as can be seen from Figure 4, the insulated hollow bolt passes in demonstration board, is being tightened with the nut (9) that insulate in the back.L type insulation strut (10) interts in insulated hollow hole (19), and mobile bead is fixed on the other end of L type pole (10), and mobile like this bead just is fixed in the chute seam (11) of demonstration board (36).Movable or the rotation insulation nut (9) with hand, mobile bead (12) is moved along chute, regulate high and low position, reach the purpose that promotes swing ball (38) and keep isometry position, in the time of need be away from swing ball (38), mobile bead (12) can be turned to highest point, from the insulated hollow bolt (46) of back quilt, twitch L type insulation strut (10) scalable and move the front and back position of bead (12), make it to be on the same swing cambered surface with swing ball.In Fig. 5 and Fig. 6, gauge outfit annulus (16) embeds in groove box (4), adsorb mutually with the magnetic stripe of installing up and down in the groove box (15), passing zeroing screw rod (17) from annulus (16) is nested with zeroing nut bar (18), going up installation nut bar snap ring (45) at zeroing nut bar (18) is close on the side panel inside and outside wall, prevent that nut bar (18) from producing the twitch phenomenon, because the oscillation system of gauge outfit is installed on the jewel screw (39) of annulus (16), so, the zero-bit of swing ball (38) is regulated, can only realize that the center of gravity of oscillation system is regulated nut (13) by turn gauge outfit center of gravity and realized by the zero-bit adjusting knob (3) that is installed on the zeroing nut bar (18).Fig. 7 can find out zeroing screw rod (17) from the side, passes from groove box circular hole.Among Fig. 8, the dynamometry screw mandrel (24) of micro-force measurement meter from line of rabbet joint mouth (25), oppositely toggles it to the other end of groove arc sealing (23) along cambered surface, is the dynamometry scope of micro-force measurement meter.Vacuolar membrane disk (26) effect is the gravity effect that alleviates disk as far as possible among Fig. 9, and the balance of easier adjusting dynamometry screw mandrel (24) makes it all be in the zero-bit point in any direction.Among Figure 10, can find out the external end head of clock and watch hairspring (27), tightly be inserted in spiral head gim peg (29), decontrol if stir dynamometry screw mandrel (24) back, vacuolar membrane disk (26) is returned to the origin-location under the tension force effect of clock and watch hairspring (27).Among Figure 11, the side that can be observed demonstration box is equipped with the magnetic stripe (33) of absorption transparent area cover plate (31), because the coboundary and the dividing plate (5) of transparent area cover plate (31) have a sealing, with hand the transparent area cover plate is moved up and down, effect is to allow the demonstration box bottom leave the space, is convenient to experimental implementation.Among Figure 12, the groove on the zero graduation left side (6) is to portray according to the swinging track of swing ball, on the right of zero position is flat line, insulated hollow bolt (8) insulation nut (9) is installed in the chute seam (11), mobile bead (12) can stitch (11) with chute and move after inserting insulated bolt hollow hole (19) by L type insulation strut (10), and lighting bulb (7) is installed in demonstration board (36) lower left corner, being apart from groove (35) below the groove (6), is deflection angle groove (34) above.Among Figure 13 and Figure 14, after gauge outfit pendulum post (37) supports on the jewel screw, the gauge outfit center of gravity adjusting screw(rod) (14) of top, regulate the turn of nut (13) by the gauge outfit center of gravity, changed below the pendulum post (37), the centre of gravity place of gauge outfit fork (2) and swing ball (38) makes swing ball (38) possess experiment condition under the microgravity state.Among Figure 15 and Figure 16, the top and bottom that gauge outfit moves annulus (16) are iron plate (41), with jewel screw (39) one side vertical be annulus screw (46), gauge outfit moves annulus (16) in groove box (4), is attached together with magnetic stripe (15) in the groove box.Among Figure 17, the middle part on groove box (4) limit has groove box cylindrical void (44), is convenient to regulate jewel screw (39) groove box circular hole with screwdriver and can therefrom passes zeroing screw rod (17).Among Figure 18, the bottom in the middle of the groove box (4) has the dividing plate line of rabbet joint, makes the gauge outfit fork (2) of swing part, can swing passing the dividing plate line of rabbet joint (43).Among Figure 19, transparent area cover plate (31) both sides are equipped with bar shaped iron plate (32), and the shading surface of lower left (30) is convenient to be in the light, in order to avoid the long-time stimulus eyes.In Figure 20, swing ball (38) and mobile bead (12) all have been with like charges, and swing ball (38) is subjected to the horizontal direction acting force of mobile bead (12), and deflection certain angle θ produces mutually apart from r, because spacing is bigger, regard them as point charge Q so long ₁Q ₂, be that two beads etc. are big, and smooth surperficial identical, band completely during electric charge simultaneously, Q ₁=Q ₂

Claims

1, a kind of physics educational apparatus, the Coulomb law demonstrator, swing ball and mobile bead as the simulation points electric charge, the two little radiuses of a ball are identical, outside surface is same metal material, its essential characteristic is, in demonstration box dividing plate top enclosure portion, open a line of rabbet joint that is parallel to the swing ball swaying direction on the demonstration box dividing plate, and fix the groove box of a built-in magnetic thing around the line of rabbet joint, interior sky is wanted to place the gauge outfit annulus, in the one side of groove box and the correspondence position boring of demonstration box lateral direction, the making of gauge outfit divides fixing and swing two parts, and annulus is installed instrument jewel screw, and adsorpting iron plate is installed in the lower edge on the annulus, change the hole at annulus perpendicular to the position of instrument jewel screw one side, pass screw rod and fixing, pass by groove box circular hole, the nut bar that stretches into the demonstration box outside is nested, the adjusted knob, make the gauge outfit annulus can move left and right, thus, the annulus part, screw rod, the nut bar, groove boxes etc. are formed the mobile support section of gauge outfit; The oscillation system of gauge outfit is made up of center of gravity adjuster bar, pendulum post, fork, swing ball etc., and pendulum post top is a barycenter regulatable balancing lever, and the below is a fork, swing ball hangs over below the fork, with the shank of pendulum post, by the jewel screw on the annulus, be supported on flexible swinging on the annulus, just become special-purpose gauge outfit; Mobile bead passes through L type strut fixation, and in the insulated hollow bolt hole on the insertion demonstration board chute.

2, Coulomb law demonstrator according to claim 1, it is characterized in that: the gauge outfit part, the center of gravity adjuster bar, end structure is a screw rod on it, screws in nut, and the middle part of bar is the appropriate location on the lower side, vertically penetrate the pendulum post, the pendulum two of leaning on is supported in the jewel screw hole on the annulus, and the aperture place, lower end of bar can inject fork, swing ball below the fork is produced freely swing.

3, Coulomb law demonstrator according to claim 1, it is characterized in that: in the lower end of gauge outfit center of gravity adjuster bar, compound fork in the grafting, the Metallic rod syringe needle of fork, aperture below gauge outfit center of gravity adjuster bar inserts, Metallic rod pin lower end connects the thin bar of insulation, penetrates metallic film lightweight swing ball then.

4, Coulomb law demonstrator according to claim 1, it is characterized in that: the demonstration panel is from the appropriate location on the parallel limit of keeping right of zero graduation in demonstration box, turn left through zero graduation and the corresponding position of swing ball motion camber line, open one section groove, penetrate in the groove with the insulated hollow screw rod, quilt cover is nested with the insulation nut behind casing, is fixed in the groove, can move along the line of rabbet joint; Mobile bead is fixed on an end of L type insulation strut, and the other end of pole inserts the insulated hollow nut, and degree of tightness is suitable, realizes the turn of control insulation strut by the insulation nut; Twitch L type insulation strut, mobile bead is done moved forward and backward.

5, Coulomb law demonstrator according to claim 1, it is characterized in that: measure the horizontal deflection power of swing ball at 45 with the micro-force measurement instrumentation, and on demonstration board, mark the value of 45 place deflection force, from the zero position of demonstration board apart from groove, on the left side, from the arc trajectory of swing ball, the correspondence camber line that draws, and on camber line angular dimension groove and apart from groove, the right parallel lines of distance scale that draw.

6, Coulomb law demonstrator according to claim 1, it is characterized in that: use the lightweight rigid foam block, be processed into uniform slim disk, insert the center of circle with a rotating shaft, and in rotating shaft the cover hairspring, an internal diameter is a bit larger tham on the cylindrical drum of foam discs, the hairspring fixed mount is installed in the inside, and the jewel screw is loaded onto at the dome center up and down, and the outer silk termination of hairspring is fixed on the hairspring fixed mount, again the rotating shaft two ends are inserted in the jewel screw hole, foam discs is rotated, on the urceolus face of cylinder of foam discs, open a line of rabbet joint mouth, end from sealing, insert a lightweight dynamometer link toward the foam discs edge, regulate the center of gravity on all directions, be placed on an end of line of rabbet joint mouth, mark 0 to peaked scale score value of F and unit at line of rabbet joint edge, just made the micro-force measurement meter.

7, the described Coulomb law demonstrator of root a tree name claim 1 is characterized in that: the frame appropriate location on demonstration box the lower partition both sides, the magnetic adsorbent equipment is installed; Do one with demonstration box wide, highly with on the demonstration box hide the transparent panel that the panel lower limb joins, demonstration box both sides frame, with last screening panel joint,, the seam of a width greater than transparent panel arranged from the partition position below, when transparent panel when the demonstration box bottom cover is to the demonstration box frame, the front is seen with last screening panel lower limb and is alignd, and promotes transparent panel up and down, and transparent panel is moved up and down in seam.

8, the described Coulomb law demonstrator of root a tree name claim 1 is characterized in that: at the inner illuminating lamp of installing of demonstration box.

9, the described Coulomb law demonstrator of root a tree name claim 1, it is characterized in that: the radius of swing ball and mobile bead is identical, and the outside surface material is identical, and the slim spherical shell of swing ball covering, outermost layer are metal film.