Abstract: This invention relates to a regenerating power unit employing a flowable medium to drive a rotatable wheel and attached axle with various attachments being utilized on the rotating axle for educational and/or amusement purposes. The power unit 10 is provided with a front and back wall 17,18 either or both of which may be transparent, and a pair of flowable medium reservoirs in fluid communication with a chambered wheel 22. A suitable adjustment valve 48 (FIG. 7) and 50 (FIG. 8) controls the rate of flow of flowable medium 39. When one medium reservoir is emptied, the power unit is rotated 180.degree. and the power unit may resume operation. A support stand 34 (FIGS. 2, 5 and 6) is employed when it is desired to permit rotation of power unit 10 without lifting thereof. Various educational and/or amusement accessories for power unit 10 are illustrated in FIGS. 9-18.