In this experiment the effects of rotation on a fluid can be observed by the Taylor
Columns formed in the tank.
To run this experiment
1. Fill the tank with water to a height of 10cm
2. Set the period anywhere from 5-20 seconds per rotation
3. Allow the fluid to achieve solid body rotation. (about 20 minutes)
4. Swirl your hand in the water to induce a motion
5. Wait for the motion to settle, but not long enough for it to dissipate (10 seconds)
6. Drop the dye into the fluid
Taylor Columns Around an Object
To run this experiment
1. Fill Tank with 12-15 cm of water
2. Put colored paper inside glass cup
3. Position the cup towards the outside of the tank upside down
about 2-3 cm from the edge
4. Set the period to 7 seconds and wait for solid body rotation (20 minutes)
in this experiment achieving solid body rotation is important for it to
work
5. Sprinkle coffee grounds into tank, near glass cup
6. Speed up or slow down rotation by 0.1 seconds
Although the object is only about 1/3 the height of the water level, the coffee grounds move around
the object as though it were the entire height of the tank. This effect can only be seen in rotating
fluids. In the previous experiment we saw how the dye forms columns that stretched out horizontally
maintaining a uniform vertical structure (because the axis of rotation is vertical). Essentially the same
thing is happening with the coffee grounds. The motion of the fluid around the object maintains a constant
vertical structure, which spans the entire height of the tank even though the object is absent at higher levels.
This is why the coffee grounds move around the the object even though it is not physically blocking them.
