Falling ball viscometer
Content of this page :
1. Introduction of the experiment.
2. Aim of the experiment.
3. Tools of the experiment.
4. Steps and methods of the experiment.
5. Parameter, Theory and Final law of the experiment.
6. Table of The Readings.
7. Medical application and advantages of the experiment.
1. Introduction of the experiment:
The principle of the viscometer is to determine the falling time of a sphere with known density and diameter within a fluid filled inside glass tube. The viscosity of the fluid sample is related to the time taken by the sphere to pass between two specified lines on the cylindrical tube.
2. Aim of the experiment:
1-To determine the viscosity of glycerin.
2-To determine how the viscosity of a liquid varies with temperature.
3-Tools of The experiment
· Cylindrical measuring tube.
· Spherical glass ball.
· The measuring tube is positioned slightly inclined about 10 to the vertical position surrounded by outer glass tube which can be filled with temperature controlled water. The assemblies is pivoted can be turned upside down.
· Water bath and stop watch.
4. Steps and methods of the experiment:
A-Determine the viscosity of the glycerin:
1-Fill the measuring tube with glycerin.
2-Put down the ball in the measuring tube.
3-Determine the falling time of the ball from ring A to ring B by using stop watch.
4-The time period starts when the lower periphery of the ball touch the ring A, and the falling time end when the lower periphery of the ball touch ring B.
5-Turn the tube 1800 again the ball return to its start position.
6-Falling time repeated three time at room temperature and then determine the average value of measuring results.
7-Find the viscosity of glycerin from the equation (1 and 2).
B-Change the viscosity of a liquid according to various temperatures:
1-Switch on the thermostat and set temperature at 40 c.
2-Wait until temperature stabilizes then measure the ball falling time.
3-Repeat the previous step at different temperature and then write results as shown in table 1
4-After completing the experiment, set the temperature on the thermostat near the room temperature and turn off the power supply.
5-Tabulate the reading.
6-Plot a graph between the temperature and the time.
7-Discuss the result.
5-Parameters, Final Law of The experiment
Parameters:
K= Ball constant =0.007 (mpa.cm /g)
ρ1= Density of ball=2.2 (g/cm3)
ρ2= Density of glycerin is 1258.6 (Kg/ m3)
t= Falling time of the ball in (s)
ν= Kinematic viscosity (cm2 /s)
η= Dynamic viscosity (mpa.s)
ρ= Density of the liquid sample (g/cm3)
Final Law:
The dynamic viscosity:
The kinematic viscosity:
6. Table of the Readings:
7 -Medical Application:
The viscosity of synovial fluid can be a good indicator to help diagnose various health conditions and can be correlated to joint pain and inflammation as well. Arthritis is one potential disease that can be monitored specifically via measurements of the viscosity of synovial fluid.