[Dr. Scott W. Tinker] From lighting to computers to cell phones to air-conditioning, electricity powers our modern world. But scientists have only known where it (electricity) is for about a hundred years. Here's a model of our solar system. Imagine that it's an atom. Atoms, of course, are the tiny building blocks that make up every substance in the universe. In the center of every atom is a nucleus with a positive electrical charge. Around it is electrons with a negative charge. Positive and negative charges attract, and it's this electromagnetic force that holds the atom together—sort of like gravity holds planets in orbit around the Sun. In some things, electrons bounce randomly from one orbit to the next. Electricity happens when we get the electrons to line up and all flow together. So, how do we do that? Remember that electrons are charged particles, they're essentially like super tiny magnets, and like magnets, they can be pulled towards or pushed away from other magnets. So, the most common way we make electrons move is by pushing them with magnets. The magnet pushes an electron out of orbit and into the orbit of another nucleus, and that pushes an electron out into the orbit of another nucleus, and so on. It's this flow of electrons from one atom to another in one direction that is electricity. Now, of course, this happens so fast (that) there's no way you can see, and it happens across many, many atoms at once. In fact, to get just one ampere of electricity (the unit we use to measure the flow of electrons) requires over six quintillions of them all flowing per second. In simple terms, that's electricity, the flow of many, many, many electrons across atoms.