A CESSNA 152, N5090Q AND A CESSNA 172, N20100 COLLIDED IN FLIGHT WHILE THE AIRCREWS OF BOTH AIRCRAFT WERE ON LOCAL DUAL INSTRUCTIONAL FLIGHTS. THE STUDENT IN THE CESSNA 152 WAS PRACTICING A RECOVERY FROM AN UNUSUAL ATTITUDE AFTER THE INSTRUCTOR (IP) PUT THE PLANE IN A LEFT DESCENDING TURN. THE STUDENT HAD HIS HEAD DOWN WHILE THE IP WAS POSITIONING THE AIRCRAFT. AS THE RIGHT WING CAME DOWN DURING THE RECOVERY, THE IP SAW THE CESSNA 172 ON A COLLISION COURSE, BUT DID NOT HAVE TIME TO AVOID A COLLISION. THE CESSNA 172 HAD PREVIOUSLY BEEN MANEUVERING AND CHANGING DIRECTIONS, BUT HAD BEEN ON THE SAME HEADING FOR ABOUT 1 MIN PRIOR TO IMPACT. THE PLANES CONVERGED ON ONE ANOTHER FROM A QUARTERING HEAD-ON DIRECTION AT ABOUT 3000 FT. AFTER THE COLLISION, THE IP OF THE CESSNA 152 TOOK CONTROL OF HIS AIRCRAFT AND MADE A SUCCESSFUL LANDING IN AN OPEN FIELD, BUT THE CESSNA 172 CRASHED.