Experiment 14. A dancing pollywog.
FIG. 28
DRAWING GLASS SPIDER-WEBS
Make a pollywog as in Experiment 12, but bend its tail twice as shown in 1, Fig. 27; the nozzle is at one side and points sidewise.
FIG. 29
THE SPIDER TRICK
Put it in the bottle full of water, then press down and release the stopper. Does it sink and rise, and does it also whirl around most beautifully as it rises?
Make another pollywog (2, Fig. 27), but bend its nozzle in the opposite direction. Does it whirl in a direction opposite to that of the first pollywog?
Put them in the bottle together and treat your friends to a pollywog dance.
The pollywog whirls because the water rushes out of the nozzle in one direction and forces the nozzle in the opposite direction.