FIG. 27
DANCING POLLYWOGS
The pollywog rises when you release the stopper because the compressed air drives the water out until the pollywog weighs less than the water it displaces.
The pollywog turns a somersault because the water rushes out sidewise in one direction and forces the nozzle in the other direction.
Air may escape from the pollywog when it is turning a somersault; if so, water will take its place, and may make the pollywog too heavy to float. You can restore its buoyancy by sucking out the water.
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.
