gee-haw whammy diddle. In theory，based on the mechanics principle of the gee-haw whammy diddle，the principle

of rotation is analyzed and its rotation characteristics are studied. The theoretical analysis shows that the iron nail

in the front end of the gee-haw whammy diddle does periodic elliptic movement，the vibration of the stick and the

iron nail drives the rotation of the propeller as well as the rotation direction of propeller depends on the phase difference

between horizontal and vertical vibration. In the experiment，the optical amplification method is used to observe

the movement process of the gee-haw whammy diddle. The experimental results agree with the theoretical analysis

results. Experiments show that the rotation direction of the propeller is related to the contact position of the

hand when the horizontal force is exerted by the hand. It is also found that the more the number of the notches are

rubbed per unit time，the higher the rotating speed of the propeller，they have a linear relationship.