You've probably felt it before. A small shock when you touch a doorknob, or your hair standing on end after taking off a winter hat. This is static electricity. Unlike the electricity that powers your lights, which flows through wires as a current, static electricity is all about electric charges that have built up on an object and are staying put, at least for a little while.

So where does this imbalance come from? It all starts with atoms. Everything is made of atoms, and atoms are made of even smaller particles: protons (positive charge), electrons (negative charge), and neutrons (no charge). Usually, objects are electrically neutral because their atoms have an equal number of protons and electrons. Their positive and negative charges cancel each other out.

But electrons aren't locked in place. When two objects rub against each other, some electrons can get scraped off one object and transferred to the other. This upsets the balance. The object that loses electrons is left with more protons, so it has a net positive charge. The object that gains electrons now has an excess, giving it a net negative charge.

This simple transfer is behind all static electricity phenomena. When you rub a balloon on your head, it pulls electrons from your hair. The balloon becomes negatively charged, and your hair becomes positively charged. Since opposite charges attract, your positively-charged hair will lift up and reach toward the negatively-charged balloon.

The same principle explains why you might get a shock from a doorknob after walking across a carpet. Your shoes rub electrons off the carpet, and your body builds up a negative charge. When you reach for the metal doorknob, which is a good conductor, all those extra electrons jump from your finger to the knob at once, creating a tiny spark you can see and feel.

Static electricity might seem like a modern nuisance, but people have known about it for thousands of years. The ancient Greeks were the first to formally describe it. They noticed that if you rubbed a piece of amber with fur, it would suddenly be able to attract light objects like feathers or straw.

In fact, the Greek word for amber is where we get our modern words "electron" and "electricity." It was the first recorded instance of humans studying the strange effects of charge imbalance, the very beginning of our journey to understanding electricity.

Let's review what we've learned about these stationary charges.

From a shocking touch to a clinging sock, static electricity is a fundamental force that demonstrates the power of stationary charges.