Video: Understanding Static Electricity

The buildup of what type of particle gives an object an electric charge?


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.

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