 At the end of the last video I said that this is the truth. If you take solid table salt and mix it with water, the sodium and the chloride from the table salt split apart from each other and they dissolve in the water. I said this is not the truth. This was an alternative idea. You take solid table salt and you mix it with water. The table salt dissolves in the water, that's what the AQ means, but the sodium and chloride never dissociate or never split apart from each other. I said how do you know this is true? Like I said, I don't expect you to know, but there's an experiment that you can do with salty water and the general idea is that salt water conducts electricity. You can say how the hell does that help us show that the sodium and chloride split apart from each other. Here's the idea. I don't pretend I know much about electricity or light bulbs, but I'm going to draw an old-fashioned light bulb. Here's an old-fashioned light bulb. That is horrible looking. Here's an old-fashioned light bulb. There's maybe a battery here. This is a wire here. The wire has electrons and the battery basically pushes the electrons around in a loop, all in one direction. Just go around and around like a merry-go-round. Basically as the electrons move along the wire, they heat up the top of the wire, the top of the wire gets hot and it glows and it releases light. That's kind of how very old light bulbs work. Then I can ask you the question, well, that's fine, but what if I snipped the bottom part of the wire so that the bottom part of the wire, those bottom parts were no longer connected? What would happen to the light? You would be correct if you said the light bulb wouldn't light anymore. The light wouldn't turn off. This is broken wire. I'm going to call this my fancy light bulb. It turns out that if I take my fancy light bulb like this and I dip it into pure water, nothing happens. Light bulb does not turn on. However, if I take my fancy light bulb and I dip it into salty water, as long as the battery is there, the light bulb turns back on. The reason for this is that remember there are electrons trying to move along this wire, there's basically they all sort of end up stuck trying to leave one end and they can't do it because the wire has been snipped. The electrons have a negative electrical charge. They're all basically piled up on one end or waiting to leave, but they can't. The sodiums in table salt, they have a positive charge. Basically they can pick up the electrons that are piling up on one wire. Because they're dissolved in water, the sodiums that have picked up the electrons can bounce around and eventually some of them will make it to the other wire and they can release the electron there. As long as there are these sodiums bouncing around all by themselves separated from the chlorides, then they can carry electrons from one wire to the other and they can complete the circle again. As long as the circle gets complete again, the light bulb will turn back on. This would only happen if the sodiums were split apart or dissociated from the chlorides. There you go, that's the exclamation. If the sodiums and chlorides never split apart from each other, then the sodium couldn't really pick up the electrons that you can think of as piling up on one end of the wire. It only happens if they're split apart. That is why this one is true, or at least that's the piece of experimental evidence that suggests that this is true, and the piece of experimental evidence that suggests that this is not true. The sodiums and chlorides actually split apart because you can take a fancy light bulb, dip it into salt water, and it'll conduct electricity. Here is my fancy light bulb, the sodiums and chlorides are charged and they're separated from each other, the light bulb has turned on. If it was this situation where they never separated, the light bulb would turn off. This is the truth, this is the real situation. There's a new word that I want you to know, and that is down here. An electrolyte is anything that is dissolved in a liquid that allows the liquid to conduct electricity. So table salt, dissolved in water, the table salt is a type of electrolyte. So I want you to know what electrolytes are. There are different kinds of electrolytes. There are strong electrolytes, there are weak electrolytes, and there are also things called non-electrolytes. Table salt, when it's dissolved in water, is a strong electrolyte. What that means is that pretty much all of the sodiums and chlorides that you throw into table salt, almost all of them will separate from each other and basically bounce around in the water separately from each other. Because they're almost all completely separated from each other, the light bulb will turn on strongly. So you say that table salt in water is a strong electrolyte because it conducts electricity very well. If it didn't do that, you could imagine a situation where the table salt sometimes it split apart like I'm showing you here, the chloride is charged, the sodium is charged, and they're not together. And sometimes they stayed connected to each other. If this was the situation where sometimes the sodiums and chlorides stayed together and sometimes they fell apart, then the light bulb wouldn't turn on as much and you would say that this stuff was a weak electrolyte. Now for table salt in water, this is the truth. But there are other materials that can dissolve in water and they'll conduct electricity but just not as well as table salt and those are called weak electrolytes. The third situation is if the sodiums and chlorides never split apart at all. Again, this is not true but I'm just using it as an example. If this was the situation, the light bulb would never turn on and you would say that your material that you dissolved in is a non-electrolyte. So there are different kinds of things that you can dissolve in water. Some of them conduct electricity very well. They're called strong electrolytes. Some break apart into charged materials or electrically charged materials a little bit. They conduct electricity not as well and they're called weak electrolytes. And some other materials dissolve in water but they don't become charged at all. Those will not conduct electricity and they're called non-electrolytes. So here's an example of a weak electrolyte. This is called acetic acid and this is the stuff in vinegar that makes it taste tart. And if you take acetic acid, dissolve it in water, some of the acetic acid molecules break apart into things that have electrical charges but they don't do it completely. So if I take a zillion of these, not all of them will turn into these charged things on the right side of the equation. Some of them will still stay like this, which means they won't be charged. So acetic acid dissolved in water will not conduct electricity as well as table salt dissolved in water. So acetic acid is a weak electrolyte. The other way that you can see this is that there's a two-way arrow here. This is kind of a common way that people show you that something might be a weak electrolyte. So the two-way arrow is basically saying, look, this acetic acid that's not charged on the right, it can turn into some things that are, sorry, this acetic acid that's not charged on the left, it can turn into some things that are charged on the right side of the arrow. But because it's a two-way arrow, some of these charged things on the right side, they can also be converted back into the stuff that's not charged at all on the left. So a little bit of this stuff on the left, a little bit of this stuff on the right, all running around together when you throw them into water. So that's a weak electrolyte. And so if you could zoom in, if you threw some acetic acid into water and you could zoom in and look, maybe some of the molecules would be uncharged and some of them would be charged and that would be a weak electrolyte. This is an example of a non-electrolyte. This is sugar. There are many different sugars that have this formula, but you can think of maybe this is a sugar called glucose because glucose is one of those things that has that formula. You have all taken sugar and dissolved it in water, I am sure. So there is this sugar when it's dissolved in water. It says AQ. But if you look, not charged, what that means is even though it's dissolved in water, the fact that it's not charged means that it's not going to conduct electricity. So this kind of sugar when you dissolve it in water is a non-electrolyte. Again, if you dissolved some of this sugar into water and you could zoom in and look, it would be dissolved. Those molecules would be dissolved in the water, but they wouldn't be charged and so the light bulb would be off. So that's a non-electrolyte. So to summarize electrolytes, some materials dissolve in a liquid and they break apart or they dissociate into charged particles, also called ions. Those things, if they break apart into charged particles, they're called electrolytes. Some don't. If they don't break apart into charged particles, they're called non-electrolytes and they don't conduct electricity. Some break apart a little bit, those are called weak electrolytes. And then finally this is kind of a wordy bullet point, but it says the amount that the material breaks apart into ions or the amount that it breaks apart into charged particles, it depends on the material that you're dissolving, but it also depends on the liquid that you're trying to dissolve into. So I have been very careful in saying that table salt in water is a strong electrolyte. But if you take table salt and try to dissolve it in other things, it might not break apart completely. So it might not be a strong electrolyte when you try to mix it with other liquids. When you mix it with water it's strong. So that's it for electrolytes. See you in the next video.