TBR Electrostatic and Electromagnetism questions =(

[ilovemedi]

I;m confused about the role of insulators and conductors. So with conductors, electrons move freely and transfer to other materials if they touch, while in insulators, they don't?

1)Say you have a glass rod, and you rube it with silk, and held it NEAR one end of another metal rod... Charges don't get directly transferred from one to another, because they're not touching directly, right?

2)Also, along the same question.... say this was repeated on a humid day (question #19 on passage 3 tbr). What would happen? Answer: experiments won't work as well because "electrostatic experiments depend on insulators being able to acquire a net charge and hold on it. Humid day = more water = better conductor = easier to recombine to make netural atom = reduces charge buildup on rods". Whaaat? Isn't the glass rod an insulator and won't be affected by more air particles in air...?

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[howlovely]

Conductors (if an object is made of metal, you can usually assume it's a conductor) allow charges to move freely through an object. If a conductor has a net charge, the charges seek to get as far away as possible from the other charges, so they end up on the conductor's surface. If you have a conducting spherical shell, the net E-field inside the shell is zero.

The charges in insulators, on the other hand, are fixed. They can't really move. You can, however, induce a charge like when you rub a glass rod with silk and hold it near an end of a metal rod.

 

[shoehornlettuce]

I;m confused about the role of insulators and conductors. So with conductors, electrons move freely and transfer to other materials if they touch, while in insulators, they don't?

1)Say you have a glass rod, and you rube it with silk, and held it NEAR one end of another metal rod... Charges don't get directly transferred from one to another, because they're not touching directly, right?

2)Also, along the same question.... say this was repeated on a humid day (question #19 on passage 3 tbr). What would happen? Answer: experiments won't work as well because "electrostatic experiments depend on insulators being able to acquire a net charge and hold on it. Humid day = more water = better conductor = easier to recombine to make netural atom = reduces charge buildup on rods". Whaaat? Isn't the glass rod an insulator and won't be affected by more air particles in air...?

1. No the charges are not transferred. The rod is polarized though; say the rod is negatively charged, positive charge will be attracted to the negatively charged rod and create an uneven distribution of charge in the uncharged rod (the distribution will only be uneven while you hold the rods close to one another though).

2. Humid air acts as a better conductor than dry air due to the water droplets in the air. Because of this, it is more difficult for the rod to hold charge. Think about winter vs summer. In the winter when the air is dry you probably notice you get shocked all the time when you touch doors in your house. The dry air makes it easier for charge to build up on you.

 

[ilovemedi]

2. Humid air acts as a better conductor than dry air due to the water droplets in the air. Because of this, it is more difficult for the rod to hold charge. Think about winter vs summer. In the winter when the air is dry you probably notice you get shocked all the time when you touch doors in your house. The dry air makes it easier for charge to build up on you.

So with the example of the glass rod, when its humid outside, even though the glass rod is an insulator, it is less capable of holding its charge due to the increased H2O molecules? Thank you for your help!