An experimental study on the structure of the short bubble and the long bubble formed on NACA 63-009 airfoil has been made. Mean velocities, turbulent stresses and turbulent triple products were measured. Results show that the turbulent stresses attain maxima near the reattachment point for the short bubble. For the long bubble, these stresses start to increase just after the laminar separation point and attain maxima far before the flow reattaches to the airfoil surface. Turbulent energy balances were estimated from results. It is shown that the turbulent energy production term has the largest contribution to the growth of turbulent energy compared with the other terms.