Maui Toys' Water Bouncer (Fig. 1) is a water‐filled ball containing glitter. Buy one and put it on your desk and students can't keep their hands off of it. Pitch the ball in the air giving it a quick spin. When you catch it you will see a sparkling vortex. Twist the ball around different ways and the angular momentum of the fluid keeps the axis of the glitter vortex fixed in one direction.
Trikosko, Walter, "Physics in a Glitter Ball" (2011). Faculty Publications. 5.