A portable apparatus and method for demonstrating different
characteristics of different fluids that includes different fluid sumps
or chambers for receiving samples of the different fluids. A test shaft
having different portions that are immersed in the different fluid
samples in the chambers is driven by an electric drive motor at a
substantially constant speed while substantially the same amount of
friction or force is applied to the different portions of the test shaft
at different times to increase the resistance presented to the drive
motor. The additional amount of current drawn or power absorbed by the
motor or strain induced in the motor drive shaft during the application
of such friction or force to the different portions of the test shaft is
monitored and compared to provide a comparison of the friction or power
loss characteristics of the different fluid samples.