Why does rubbing a comb attract tissue paper?

[chase222]

Tomorrow I have to do a demo in physics regarding static electricity. I am going to rub a comb against the inside of my sweatshirt and then attract tissue paper to it. I don't understand how to explain why this happens.

Is the comb neutral at first, then when you rub it to the sweatshirt it gains electrons and has a negative charge? Is the tissue paper a positive charge because opposites attract? Please explain this to me if I am wrong. Thanks!

 

[Doc Al]

polarization force

Is the comb neutral at first, then when you rub it to the sweatshirt it gains electrons and has a negative charge?

That's right.

Is the tissue paper a positive charge because opposites attract?

The tissue paper is neutral (no net charge), but the field from the charged comb polarizes the atoms in the paper. Since the positive charges in the paper are closer to the negative comb than the negative charges are, there is a net attractive force (called a polarization force) between the paper and the comb.

 

[wais]

You are on the right track! When you rub the comb against your sweatshirt, the comb gains electrons from the sweatshirt, giving it a negative charge. The tissue paper, on the other hand, has an overall positive charge. This is because the atoms in the tissue paper have a slightly higher number of protons than electrons, making it positively charged. Opposites do attract, so the negatively charged comb will attract the positively charged tissue paper. This phenomenon is known as static electricity, where objects with opposite charges are attracted to each other. The transfer of electrons from one object to another is what causes this attraction. It's important to note that the charges are temporary and will eventually dissipate, but it's a great way to demonstrate the principles of static electricity. I hope this helps and good luck with your demo tomorrow!