Physics Lab Equipment

LEMI-32 Measuring Liquid Viscosity - Falling Sphere Method

LEMI-32 Measuring Liquid Viscosity - Falling Sphere Method


  • Photoelectric timing

  • High accuracy

  • Affordable


Viscosity coefficient is one of the important properties of liquid. Measurement of liquid viscosity coefficient using a falling sphere can reveal related physical phenomena clearly. Normally, the measurement accuracy of the falling ball method is not high by using a manual stopwatch considering the existing parallax errors of the sphere.


This apparatus is designed with the following benefits:


1. Using photoelectric sensor and electronic timer to avoid the parallax and timing errors caused by a stopwatch

2. Improved mechanical design to ensure precise falling trace of the sphere

3. Using laser ranging to accurately measure both the fall time and fall distance to avoid the parallax error


Using this apparatus, the following experiments can be conducted:


1. Measure the viscosity coefficient of a liquid using falling sphere method

2. Use a photoelectric sensor for timing experiment

3. Use a stopwatch to time a falling sphere, and compare results with the photoelectric timing method

Main Specifications

Electronic timerDisplacement range: 400 mm; resolution: 1 mm
Timing range: 250 s; resolution: 0.1 s
Measuring cylinderVolume: 1000 mL; height: 400 mm
Measurement error<3%

Part List 

Stand Rack1
Main Machine1
Laser Emitter2
Laser Receiver2
Connection Wire1
Measuring Cylinder1
Small Steel Ballsdiameter: 1.5, 2.0 and 2.5 mm, 1 each
Magnet Steel1
Power Cord1

  LEMI-32 Measuring Liquid Viscosity - Falling Sphere Method.png

Schematic diagram of apparatus

1. Guide tube

2. Laser emitter A

3. Laser emitter B

4. Laser receiver A

5. Laser receiver B

6. Measuring cylinder

7. Back panel

8. Power socket

9. Laser control

10. Front panel

11. Timer

12. Power switch

13. Timer reset

 LEMI-32 Measuring Liquid Viscosity - Falling Sphere Method.png

Viscosity of castor oil

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