Abstract: The underwater play ball is comprised of a hollow cavity with a spherical shape which is made of a strong flexible lightweight low density PVC material for holding both water and air pressure without rupturing. The cavity size and dry weight can vary, but the preferred cavity size equals the size of a average soccer ball where the dry weight is easily handled by children. The cavity is inflated with a safe rubber nozzle attachable to any size hose. The cavity includes a predetermined transparent level mark arranged around two valves at one end of the cavity. The water volume and air pressure inside the cavity is adjusted by filling water through a valve while releasing ambient air simultaneously through a second valve until the water volume and air pressure reaches a predetermined transparent fill level mark.

Abstract: A gyroscopic diving toy is comprised of a housing and a motor positioned inside the housing. A battery compartment is arranged adjacent the motor for receiving a battery. A swim bladder and a ballast are arranged inside the housing to provide neutral buoyancy and balance. A propeller is attached to an axle of the motor protruding through the housing. The axle of the motor is coaxial with a longitudinal spin axis of the housing. The housing is generally circular about the spin axis for minimizing drag when spinning. When the motor is activated, the housing is spun rapidly in a direction opposite to the rotation of the propeller, and gyroscopic forces generated by the rotation of the housing cause the toy to repeatedly dive and surface automatically for amusement.