 If you're like most people, you've probably played around with static electricity at some point. Maybe you've rubbed a balloon on your hair and made it stick to your head, or to the wall, or maybe you've tried to rub a balloon on your cat's fur and stick the balloon to your cat. This is something I do not recommend since cats usually don't like when you do this. The reason you can do this is because of something called electric charge, which we sometimes just call charge. Charge is really important in chemistry. It's what keeps atoms together. Charge is the reason that atoms can form bonds to become compounds. So without charge there would be no atoms or molecules. There would also be no people or cell phones or frappuccinos or pizza, and this alpaca would not exist. That's why you should care about electric charge. This alpaca cares, so should you. So what is electric charge anyway? According to Wikipedia, electric charge is a physical property of matter that causes it to experience a force when placed in a magnetic field, something like this. But if you haven't spent a lot of time in a physics lab, this may not make a lot of sense, and that's okay. What you do need to know is that charge is a physical property, and when two charged objects come together, they exert a force on each other. A force is a scientific name for a push or a pull. The force that charges exert on each other is called electrostatic force, or coulomic force. You'll hear both terms used. Charge comes in two different types, positive and negative. And there are three ways that positive and negative charges interact and exert coulomic forces on each other. Charges that are of the same type, we call these like charges, exert a pushing or repelling force on each other. That means if you try to put two positive charges near each other, they will repel each other or push away from each other. If you try to put two negative charges near each other, they will also exert a pushing or repelling force on each other. Particles that have opposite charges attract. This may remind you of magnets, where if you put two north ends next to each other or two south ends next to each other, the magnets repel each other and push each other apart. Or if you put a north end next to a south end, the magnets will attract each other. But coulomic forces, also called electrostatic forces, are not the same as magnetic forces, even though they seem to have similar pushing and pulling behaviors. So let's go back to the balloon and the cat. If you rub a balloon on your cat, the balloon develops a negative charge and the cat's hair develops a positive charge. Opposite charges attract, so the balloon sticks to your cat. So what do charges have to do with chemistry? Well, everything. And we'll talk about some of these things in future videos. In summary, charge is very important in chemistry. Charges can be positive or negative. Charges exert a force on each other called the coulomic force. Particles that have the same charge repel each other. Particles that have opposite charges attract. And don't try to stick a balloon to your cat. He won't like it.