bobbing

Bobbing refers to a vertical up-and-down motion of an object or person relative to a reference level. The motion arises when a body is disturbed by waves, currents, or mechanical forces and remains in partial contact with a supporting medium.

In water, floating objects such as boats, buoys, or logs exhibit bobbing as they rise and fall with surface waves. The frequency and amplitude depend on buoyancy, mass distribution, wave characteristics, and drag. In engineering and physics, bobbing is often modeled as a damped oscillation of a mass attached to a fluid through buoyancy and drag forces.

Bobbing appears in human activity as a playful game—bobbing for apples—in which participants try to catch fruit floating in water. People also experience natural head bobbing during walking, an unconscious vertical motion that helps stabilize vision.

In entertainment and animation, bobbing is used to convey movement or weight shifts, such as head bob or camera bob to imitate walking. In fishing, the bobber or float rises and falls with the line, signaling depth and bites.