Solution:The automatic watches do not require batteries for power to run. They obtain their energy from the movement of the wearer's hand. If these watches are not worn for 2 to 3 days by a person, they will stop.
Here's how it works:
Rotor: Automatic watches contain a weighted rotor that is free to spin on a pivot.
Kinetic Energy Conversion: As you move your wrist throughout the day, the rotor spins due to gravity and the inertia of your movements.
Winding Mechanism: This spinning motion is transferred through a series of gears to the mainspring, which is the power source of the watch. This process essentially "winds" the watch automatically.
Power Reserve: Once fully wound, the mainspring stores enough energy to keep the watch running for a certain period (typically 36-48 hours) even when it's not being worn. This is known as the power reserve.