Video Transcript
The buildup of what type of
particle gives an object an electric charge?
In this question, we’re
answering what particle it is that gives an object an electric charge. Let’s say we start out with
some generic object. Here’s our object. At the outset, we’ll say that
this object is electrically neutral. Now, we knew that it doesn’t
mean it doesn’t have any positive or negative charges in it. It just means that those
charges balance one another out. There is the same number of
positive and negative charges in this object.
Speaking of positive and
negative charges, just what is it that creates those charges? To answer that question, let’s
recall the structure of an atom. An atom consists of a
positively charged nucleus made up of protons and neutrons orbited by negatively
charged electrons. So really, it’s those three
particles protons, neutrons, and electrons, which are our candidates for the
particle that gives an object an electric charge. And we know that it’s electrons
that are responsible for negative charge, protons for positive charge, and that
neutrons — true to their name — have no electric charge.
So then, these are our options
for this answer of what particle gives objects electric charge. And really, we can cross the
neutron off the list because we know that that has no net charge to it. So then, we’re down to
electrons and protons.
Getting back to our object,
let’s say that this is a solid object. It’s not a liquid or a gas, but
rather in a solid state of matter. That means if we were to zoom
way in on a small portion of this object, we would see a very orderly atomic
structure to the atoms. They’re arranged in an even
grid formation. The atomic nuclei here are
drawn in pink and then the orbiting electrons are drawn in blue.
Thanks to this lattice
structure, the orderly arrangement of all the atoms, it’s the nuclei — the pink
dots — that are fully fixed in place. They can’t move without causing
a great disruption. And so, they’re very unlikely
to. The electrons on the other hand
— those blue dots — are much more mobile than the positively charged nuclei.
Now let’s say we were to shift
our view so that now we’re looking at an up-close view of a portion of our
object on the edge of the object. And just like before, we see
this evenly spaced atomic structure, the atomic lattice. And let’s say that in addition
to our original object, we now have a second object, also electrically
neutral. If we were to bring these two
objects into contact and perhaps rub them together, then what we would see is
that charge transfer is likely to occur between them.
And what charge do you think it
will be that will move from one object to the other? Rather than the fixed in place
positive charges bound to the nucleus, it will be the more mobile electrons that
will transfer between objects. It’s the exchange of those
particles — negatively charged electrons — that give objects their electric
charge. And that then is our
answer. Even though both electrons and
protons have the capacity to give an object charge, practically speaking it’s
electrons that transfer between objects and build up that electric charge.
