How does rubbing act as a mechanism for charge transfer.

[scibler]

Homework Statement

I don't understand why it is that by rubbing things together things develop charge, whereas when you just leave them close together they become discharged. What is it about the rubbing that acts as a mechanism to allow charge to flow? Isn't it the case that when rubbing doesn't occur the charges reverse their flow?

The Attempt at a Solution

I understand that by rubbing things together electrons transfer to the one with more electron affinity. I also understand that friction is primarily an electric interaction. I think it may be some sort of heat driven thing, whereby heating the surfaces you allow electrons to have more energy to liberate. However, I am not sure, and I can't seem to find anything about it in my textbooks. What confuses me most is that when not rubbing them together the charge dissipates into the air, or back between the substances.

 

[Jhero]

Hello there,

You are on the right track with your understanding of rubbing causing electron transfer and friction being an electric interaction. Let me explain it in a bit more detail.

When two objects are rubbed together, the friction between them causes the transfer of electrons from one object to the other. This is because friction generates heat, which in turn gives the electrons more energy to move from one object to the other. This movement of electrons is what creates an electric charge on the objects.

Now, when these charged objects are left close together, the charges on them start to repel each other. This repulsion causes the charges to spread out and eventually neutralize each other. This is why the objects become discharged when left close together.

However, when rubbing doesn't occur, the charges do not reverse their flow. They either stay on the objects or dissipate into the air. This is because the lack of friction does not provide enough energy for the electrons to move and transfer between the objects.

I hope this helps to clarify your understanding. If you have any further questions, please feel free to ask. Keep exploring and learning!