Charging by Conduction
Charging by Conduction
We are going to take a look at the process of charging by conduction. Now, it is similar to charging by induction, except in this case, the material transferring the charge actually touches the material receiving the charge. What happens is, a negatively or positively charged object is touched to an object with a neutral charge.
Here we have a sphere, and this sphere has a neutral charge, so it has the same amount of electrons as protons, the same amount of negative charges as positive charges. Now an object comes in, (this square looking object right here) and it has an excess of electrons, so it has an excess negative charge.
Now upon touching the sphere, some of these excess electrons move into the sphere, so now what happens is this sphere takes on a negative charge–before it was neutral, but now it’s negative because it has more electrons than protons. Now some of these excess electrons moved into this sphere, so now there is not as many excess electrons over here.
Now this object still has a negative charge, because it didn’t get rid of all the excess, but it got rid of some. What happened here is the electrons moved into the sphere. Now over here we have a similar process going on, but this time the object coming in and touching the sphere has an excess positive charge.
Now the reason it has an excess positive charge is not because it has excess protons, it’s because it’s missing electrons. Conduction centers around the moving around of electrons, not protons. What happens here, as the object touches the sphere, the extra protons don’t move into the sphere what happens here is that electrons move into the object, so electrons move from the sphere to the object.
Now what happens here, is that the sphere takes on a positive charge because (now that it’s missing protons it has, excuse me) now that it’s missing electrons it has a positive charge. Now this object over here that touched the sphere no longer has such a strong positive charge, because the electrons going into it balance it out somewhat.
Now, notice what happened here. We had a negatively charged object touch the sphere, and that gave the sphere a negative charge. Then we had a positively charged object touch the sphere, and that gave it a positive charge. Whatever the charge of the object touching the neutral object, that’s what the charge of the neutral object is going to take on.
What’s happening here, as I said earlier, electrons are just flowing into or out of the neutral object and then making that neutral object charged. Now insulators cannot be used to conduct charges. Charging by conduction can also be called charging by contact. Now, one last thing.
The law of conservation of charge states that the total number of units before and after a charging process remains the same. Again, no electrons here have been created or destroyed, they’ve just been moved around. Now there’s another term called grounding, and that’s the removal of a charge on an object by conduction.