Physics Lab Equipment

  LEMI-47 Cavendish Balance for Measuring Gravitational Constant.png

Schematic of system


1 nut                         2 angle knob

3 nut                         4 pointer disc

5 scale disk              6 screw

7 screw rod              8 wire

9 glass                     10 connector

11 connector           12 mirror

13 knob                   14 rest

15 small ball            16 damping box

17 damping piece   18 main body 

19 swinging table    20 scale

21 base                   22 level

23 foot                     24 slide

25 support               26 large ball

27 pipe                    28 oil holder

29 screw                 30 screw

31 clip                     32 oil box

33 rest arm             34 screw rod


 LEMI-47 Cavendish Balance for Measuring Gravitational Constant.png

Plot of inverse square ratio

LEMI-47 Cavendish Balance for Measuring Gravitational Constant

LEMI-47 Cavendish Balance for Measuring Gravitational Constant

Features

  • Clear physics concept

  • Compact, stable, and reliable

  • Affordable





Introduction

LEMI-47 is a compact instrument for measuring the gravitational constant and verifying the gravitational effect based on an elaborately designed Cavendish balance (torsion pendulum). It uses a reflected laser beam to monitor the damped harmonic oscillations of the balance with two large spherical masses in both positions. From the period of the oscillation, the position of the equilibria, and the geometry and masses involved, the phenomenon of the universal gravitation between objects can be qualitatively observed and the gravitational constant can be quantitatively measured.

 

Using this apparatus, the following experiments can be conducted:

 

1. Measure the inherent oscillating cycle of a torsion balance

2. Measure the gravitational constant with two methods: the final deflection method and the acceleration method

3. Verify the gravitational force between two objects is inversely proportional to the square of their distance


Specifications

DescriptionSpecifications
Mass of lead balls2 large balls: 1.5 kg each,  mass difference between the two balls < 2.0 g
2 small balls: 20 g each,  mass difference between the two balls < 0.5 g
Beam of torsion balanceLength: 100 mm
Wire of torsion balanceFree torsion oscillating cycle: 580 ±10 s, length: 150 mm, area: 0.145 × 0.008 mm2
Damping mediumOil
UncertaintyMeasurement error of gravitational constant: < 15%


Accessory List

DescriptionQty
Large lead ball2
Magnet bar1
Support pipe2
Slide2
Leveling screw3
Beryllium brass wire5
Damping oil cylinder1
Holder of cylinder1
Screw for holder1
Clamp1
Screw for clamp1
Nut for clamp1
Oil bottle (damping oil)1
Oil pipe1


  LEMI-47 Cavendish Balance for Measuring Gravitational Constant.png

Schematic of system


1 nut                         2 angle knob

3 nut                         4 pointer disc

5 scale disk              6 screw

7 screw rod              8 wire

9 glass                     10 connector

11 connector           12 mirror

13 knob                   14 rest

15 small ball            16 damping box

17 damping piece   18 main body 

19 swinging table    20 scale

21 base                   22 level

23 foot                     24 slide

25 support               26 large ball

27 pipe                    28 oil holder

29 screw                 30 screw

31 clip                     32 oil box

33 rest arm             34 screw rod


 LEMI-47 Cavendish Balance for Measuring Gravitational Constant.png

Plot of inverse square ratio

Copyright © Lambda Scientific Systems, Inc. 2010-2017. All rights reserved.