CN2543042Y

CN2543042Y - Improved Joly balance

Info

Publication number: CN2543042Y
Application number: CN 01222687
Authority: CN
Inventors: 刘传安
Original assignee: LIU CHUAN'AN
Current assignee: Yichun University
Priority date: 2001-05-17
Filing date: 2001-05-17
Publication date: 2003-04-02
Anticipated expiration: 2011-05-17

Abstract

An improved joly balance is an instructional instrument in physics, wherein a ruler with a precision of 0.1 mm is added under a small platform of a current joly balance to measure a distance of the movement of the small platform. A lower end of a spring must be kept fixed when the joly balance is used, therefore when the top of the spring is pulled upward, the small platform will move downward; however, the current joly balance can only measure the upward pulled distance of the spring, and the downward moving distance of the small platform is usually measured by a repeated operation of a long and thin metal screw mandrel to replace the spring; the improved joly balance can measure the moving distance of the small platform besides the upward pulled distance of the spring.

Description

The modified Joly balance

Affiliated technical field

The utility model is a kind of physics educational apparatus of institution of higher education.See Fig. 1, in measuring solid or fluid density, surface tension experiment, often use it.

Background technology

Joly balance in use must keep the spring lower end to fix, so when mentioned the spring upper end, chain-wales (being placed with the glass dish that testing liquid is housed on it) will move down.Present joly balance can only directly be read the distance that mention spring upper end, and the distance that chain-wales moves down is with fine wire bar replacement spring, repetitive operation one time and recording.See " Lab of General Physics " such as Yang Shu forces (one, mechanics, calorifics part), Higher Education Publishing House, version in 2000, the 211st page.According to theory of errors, " to same amount, carrying out repeatedly duplicate measurements under the same conditions, is equal precision measurement.With a series of measurements that the same range or the measurer of same instrument are done different value, also think equal precision measurement." (see Li Huaping " error evaluation of physical measurement " Beijing Higher Education Publishing House version in 1993, the 5th page.) visible front and back record the elongation of spring and the displacement of chain-wales is not equal precision measurement.

Summary of the invention

In order to solve in the Joly balance measurement is not the equal precision measurement problem, and the utility model provides a kind of modified Joly balance.It is equal precision measurement that the modified Joly balance not only guarantees in measurement, and operation is very easy.

The technical scheme that its technical matters that solves the utility model adopts is: under the chain-wales of Joly balance placement glass dish a millimeter rule is installed, one 10 calibration vernier is installed, the vernier scale that to form a precision jointly be 0.1mm on chain-wales lifting nut limit.See Fig. 2.The modified Joly balance in the distance of carrying, can accurately, directly record the distance that chain-wales moves on recording spring in measurement, need not to do twice, and guarantees it is equal precision measurement.

Description of drawings

Below in conjunction with accompanying drawing the utility model is further specified.

Fig. 1 is an installation diagram of the present utility model.

Fig. 2 is the measurement mechanism structural map in the utility model.

A. principal post among the figure, B. has the traveller of scale, and V. is fixed on the vernier of A post upper end, D. measuring spring, the knob of E. lifting B post, G. cruciform tinsel, M. the level crossing that has graticule, P. garden shape glass tube, the I. scale pan, C. " day " shape silk, H. chain-wales is placed with the glass dish that testing liquid is housed on the platform, S. chain-wales elevating screws, F. the millimeter rule, K.10 calibration vernier.

Embodiment

In Fig. 1, principal post A has the garden cylindricality traveller B of scale, be fixed on the vernier V of A post upper end, as twisting E, lifting B post is mentioned or when reducing spring D, scale from the B post and vernier V are readable that spring is mentioned or the reading when reducing, and in view of the above, can calculate the distance that spring is mentioned or reduced.Cruciform tinsel G has the level crossing M of graticule, the graticule according to G and G on the picture in M and the M, and three-way alignment can make the spring lower end immobilize.Garden shape glass tube P, scale pan I, " day " shape silk C is placed with the glass dish that testing liquid is housed on the chain-wales H, chain-wales elevating screws S.Be fixed on the millimeter rule F below the chain-wales, form vernier scale with the 10 calibration vernier K that are installed in chain-wales lifting nut limit.When turn S uses chain-wales to move up and down, can accurately, directly record the distance that chain-wales moves according to vernier scale, and guarantee that whole measuring process is equal precision measurement.

Claims

A kind of modified Joly balance, its technical characterictic are that the measuring mechanism of measuring chain-wales displacement has been installed under the loading chain-wales.