Fill a clear plastic bottle about three-quarters full with water
Add a few drops of dish soap
Add a pinch of glitter, small beads, or food coloring if desired
Screw the cap on tightly
Hold the bottle by the neck and flip it upside down
Swirl the bottle in a circular motion for a few seconds
Stop swirling and watch the vortex form
Repeat the swirl if needed to make the tornado stronger