Viscosity Of Glycerin Measurement using Photogates

A body moving in a fluid is acted upon by a frictional force in the opposite direction to its direction of travel. The magnitude of this force depends on the geometry of the body, velocity of the body, and the internal friction of the fluid. A measure for the internal friction is given by the dynamic viscosity η. For a sphere of radius r moving at velocity v in an infinitely extended fluid of dynamic viscosity η, the frictional force according to Stokes' law is given as:
F1=6.π.η.r.v
In the present setup, the viscosity of glycerin is found by allowing a steel ball to fall through a column of glycerin and measuring the time taken by the ball to cover a known distance, where the photogates are attached. The steel ball is released using an electromagnet and simultaneously time is measured with photogates.

Features:

• Digital timer with membrane keypad.
• Automatically releasing the ball from the Solenoid.
• Transparent long glass tube.
• Strong heavy base.

Objectives:

• To determine the viscosity of glycerin using photogates.

Technical Data:

• Digital timer & photogate : 2 line LCD Display , Micro controller based, Time resolution 0.1ms, Mode Time, Speed & Acceleration, Photogate, USB Interface, Operating voltage 5V DC
• Photogate : Infrared source: Peak at 880 nm, Output is Low and LED off for unblocked gate,Output is High and LED on for blocked gate.
• Solenoid : Cu Coil, Resistance 10ohm, 4mm Connection to Solenoid Driver, Size 75 x 100 x 40 mm
• Solenoid Driver : Size 75 x 100 x 40mm, USB Connection to Digital timer, LED indicator.
• Experimental Stand : Height 1300 mm , Heavy ‘A’ shape base, c clamp, ‘U’ Channel Stand, 1200 mm printed scale, 2 levelling screws.
• Tube : Glass material, Length 1100 mm, Diameter 50mm.

Scope of Delivery:

• 1 Glass tube
• 3 Ferrite magnet
• 1 Electromagnet Coil
• 1 Solenoid driver with Adaptor
• 5 Glycerin (500 ml)
• 1 Flexible plug lead, 2m black
• 1 Flexible plug lead, 2m red
• 1 Free fall setup with ‘C’ clamp
• 1 Digital timer with Adaptor
• 2 Photogates
• 3 Steel ball 5.5mm, 11mm and 16mm dia.

Key Topics:

• Viscosity
• Terminal velocity
• Settling time.
• Glycerine.