How long should you rub the spoon on the dish cloth?

Rubbing the spoon on the dish cloth for about 10 seconds is ideal for generating sufficient friction. This time frame allows for the buildup of static electricity on the spoon due to the transfer of electrons from the cloth to the spoon's surface. If the rubbing is too short, the contact may not be enough to create a noticeable electrostatic charge. Conversely, if it's prolonged significantly, the effectiveness might plateau, or the spoon may not gain a substantial increase in charge. This balance of time is crucial in experiments related to electrostatics and understanding how non-contact forces like electrostatic attraction and repulsion begin to manifest.