Spins
Usually, when you fly, and one wing drops it soon finds a force support that pushes it back up. This upward force stops the wing from going down even more.
The other wing, by going up, reduces it own lift that, in turn, prevents it from going up more.
It is an equilibrium effect that tends to stabilize the plane and make your day easier.
Movement of the wing actually in motion downward causes a Relative Wind that blows upward. At the wing tip of the downward moving wing the movement of the tip is much greater than at the root of the wing. This means the upward Relative Wind is greater. (Keep in mind the Relative Wind is not coming at you - it is the wing coming at air)
When this upwardly directed Relative Wind due to the wing going down combines with the backward directed Relative Wind caused by the forward motion of the plane, the total result is a slight upward force Relative Wind that that slows and eventually stops the wings downward motion.
Net result, whenever a wing dips down it always increases its own Angle of Attack. The increase in the Angle of Attack forces a mass of air molecules downward that results in an upward force that gently stops the downward movement of the wing. As soon as the wing stops moving down the whole effect stops. It does not tend to bring the wing up. It does not stabilize the plane by returning it to its normal condition. Basically it makes the airplane steadier, less sensitive and less ready to roll. It makes the plane easier to control.
Once the plane stalls, however, the effect reverses itself. A stalled plane is laterally unstable and the slowing of the wing downward doesn't occur. The wings Angle of Attack increases at the same time the stall happens. It doesn't find a cushion of new lift and continues to destroy even more of its lift as the Angle of Attack increases and the wing continues its downward movement.
Meanwhile the other wing continues to go up and reduces its Angle of Attack and gains more lift and wants to continue up.
A stalled plane is laterally unstable and unable to slow the movement down, of one wing, and the movement up of the other wing. The more a wing drops the more it wants to drop and vice-versa.
The plane keeps itself "stalled." This is the beginning of autorotation. If this happens on an airplane in flight centrifugal force begins to build and the different amounts of drag on the two wings creates the kind of motion called a spin.
Your instructor will teach you how to exit from a spin, prevent a secondary stall and stabilize in level flight.
Notice how Angle of Attack is prominent in this discussion.
