Charged Teflon Rod & Aluminum (Conductor vs Insulator type question)

Oct 2011
Just wanted to check my some of my reasoning to these. If anyone could confirm if these answer I got are right (or point me in the right direction if they aren't!) I'd really appreciate that. Thanks!


Suppose a student rubbed a Teflon rod with wool then briefly touched it to an initially neutral aluminum rod suspended by insulating threads.

What would the net charge on the Teflon rod be?
I said the net charge on it would be NEGATIVE because it becomes negatively charged due to being rubbed with the wool, and while some of the electrons escape when touched to the aluminum, not all of them do because teflon is an insulator so within the teflon rod itself, they couldnt move closer to the aluminum point-of-contact to escape

What would the net charge on the aluminum rod be?
I said the net charge on the aluminum rod would also be NEGATIVE because it received some electrons from the point of contact with the Teflon rod

The student then holds the Teflon rod near the aluminum rod, but does not allow them to touch. The student observes that when the rods are close enough together, they attract. Explain why the rods are attracting each other.

I said they are attracting because the point of contact on the Teflon now doesn't have electrons because they were able to leave and transfer to the aluminum (making that point positively charged). So now, when that rod's point of contact is brought near the negatively charged aluminum, they attract each other, despite both rods having overall negative charges

...any faulty reasoning, or does this look good? Thanks for any feedback!!