C172RG PLT AND STUDENT INADVERTENTLY RAISE THE LNDG GEAR ON TKOF; GEAR COLLAPSES; PROP STRIKES RWY; ACFT DEPARTS THE RWY.

Narrative

MY STUDENT AND I PULLED OUT ONTO RWY 36 AT SKYHAVEN ARPT TO CONDUCT A NORMAL TKOF. AS WE BEGAN THE TKOF ROLL; WE NOTICED THE CARB HEAT WAS STILL ON. MY STUDENT REACHED OVER TO TURN IT OFF. THAT'S WHEN I NOTICED THE LNDG GEAR LEVER WAS IN THE UP POS. SEEING THIS DID NOT REGISTER AS WE WERE CONTINUING THE TKOF ROLL. AS WE APCHED ROTATION SPD; SHE (MY STUDENT) ROTATED AND THE NOSEWHEEL COLLAPSED; AS IT DID THE PROP STRUCK THE GND. MY FIRST REACTION WAS TO TAKE CTL OF THE ACFT. I PULLED BACK ON THE YOKE AND WE BECAME AIRBORNE. I BELIEVE THIS IS WHEN THE MAIN GEAR CAME UP. REALIZING WE HAD JUST HAD A PROP STRIKE; I PULLED THE THROTTLE OUT AND LANDED THE AIRPLANE TRYING TO KEEP THE NOSE UP AS LONG AS POSSIBLE. AS THE ACFT SKIDDED TO A STOP; I ADDED A LITTLE R RUDDER TO EXIT THE RWY ONTO THE GRASS. ONCE STOPPED; I SECURED THE ENG. AFTER DETERMINING NEITHER OF US WERE INJURED; I ADVISED MY STUDENT TO GET OUT OF THE ACFT. AFTER REFLECTING ON THE INCIDENT; I REALIZED THAT MY STUDENT MUST HAVE ACCIDENTALLY RAISED THE LNDG GEAR HANDLE AFTER THE LAST LNDG WE DID IN ADDITION TO THE OTHER ITEMS IN THE AFTER LNDG CHKLIST.