• Definition: Damping refers to forces, like friction, turbulence, air resistance, etc., that cause the amplitude of an oscillation to decrease over time.
• Direction: Damping forces act in the opposite direction to the resultant restoring force of the system.
• Relation to speed: Damping generally increases with speed. It's most significant when the system is at its equilibrium point (maximum speed), and least (often zero) at the maximum displacement (zero speed).
• Effect on energy: The system must do work to overcome damping, transferring energy from the kinetic energy of the oscillator. Over time, the total energy of the system decreases.
• Effect on time period and frequency: Damping increases the time period (and decreases the frequency) of the oscillation. This effect is only noticeable when the damping is large.

• Light Damping: When damping is small, the oscillation resembles that of simple harmonic motion with small energy loss over time. The time period and frequency of the oscillator remain largely constant.
• Heavy Damping: In an over-damped system, there is no oscillatory behavior. The system takes a long time to return to the equilibrium position after release.
• Critical Damping: This occurs when the oscillator takes the minimum possible time to come to rest. It transitions quickly to a rest position at equilibrium, transferring energy at the maximum rate. Important in applications like fire-door closure mechanisms and car suspension systems.

Consider a pendulum swinging back and forth. As time goes on, it slows down and eventually stops due to air resistance (damping). The energy of the pendulum is transferred to the air molecules, slowing it down.