The discussion revolves around the behavior of a negatively charged rubber rod when held in hand, particularly focusing on why it retains its charge despite being in contact with a person. The subject area includes concepts of electrostatics and charge transfer, specifically relating to insulators and conductors.
The discussion is active, with participants providing insights into the behavior of insulators and charge localization. Some guidance has been offered regarding the mechanics of charge transfer, but questions remain about the differences in behavior between the rubber rod and other materials.
Participants are navigating assumptions about charge transfer mechanisms and the properties of materials involved, particularly the distinction between insulators and conductors. There is an acknowledgment of confusion regarding the conditions under which charge can be transferred.
hi rest_7, welcome to PF.reset_7 said:When you rub a rubber rod with fur it becomes negatively charged. How does it keep it's charge if it's in your hand?
rl.bhat said:hi rest_7, welcome to PF.
Unlike the metal rod, rubber is an insulator, in which charges are localized. They won't conduct through it to your hand to conduct to the ground. Due to this same reason you cannot charge the metal rod by holding it in your hand.
rl.bhat said:When you bring a negatively charged rubber rod near an uncharged pith ball, electrons on the pith ball are repelled back due to the repulsive force leaving the surface near the rod positively charged. When you touch the pith ball with the rod, electrons are transferred from the rod to the pith ball.
willem2 said:The charges can only go from the surface of the rod, directly to anonther object that's touching the surface. If you swiped the entire surface of the rod with your hands, you could discharge it as well.