Static electricity is the invisible force that creates moments like when a sock clings to a shirt fresh out of the dryer or a balloon sticks to a wall. Static electricity is not electricity that flows in a continuous stream, like the power running to a light bulb. Instead, it is a build-up of electric charge that sits still, waiting to find a path to move. This phenomenon is why you sometimes get a tiny zap when you touch a doorknob after walking across a carpet. It is all about an imbalance of tiny pieces that make up everything around us.
The Tiny Pieces That Make Things Zap
All matter is made of tiny building blocks called atoms. Atoms are composed of smaller particles that carry an electric charge. Protons, found in the center of the atom, carry a positive charge. Electrons move around the outside and carry a negative charge.
Normally, every object has an equal number of protons and electrons, meaning the positive and negative charges cancel each other out. This balanced state is called electrically neutral. Static electricity occurs when there is an imbalance in these charges. An object that loses electrons becomes positively charged, and an object that gains electrons becomes negatively charged.
How Things Get Charged Up
Objects become charged when electrons move from one material to another. The most common way this happens is through the triboelectric effect, which means rubbing two different materials together. When you rub a balloon against a wool sweater, the friction causes electrons to be pulled away from the sweater and transferred onto the balloon. The balloon now has extra electrons, giving it a negative charge.
The sweater, having lost some electrons, now has a positive charge, leading to a strong attraction between the two objects. This transfer occurs because different materials have a different “grip” on their electrons. Some materials, like rubber, hold onto electrons tightly, while others give them away more easily. Rubbing provides the contact and energy needed for the electrons to transfer.
Fun Static Electricity Tricks You Can Do
You can use this electric force to perform several simple activities at home. One classic trick involves using a charged balloon to make a stream of water bend. First, rub the balloon vigorously on your hair or a wool cloth to build up a negative charge. Then, turn on a faucet so the water flows out in a thin, pencil-sized stream.
As you slowly bring the charged balloon close to the water stream, the water will appear to bend toward the balloon without touching it. The negatively charged balloon attracts the positive charges within the water molecules, pulling the stream sideways. Another experiment is the salt and pepper separation trick. Mix salt and pepper together in a small pile on a plate.
Charge a plastic spoon or a balloon by rubbing it quickly on a piece of fabric. When you hold the charged object just above the mixture, the lighter pepper flakes will jump up and stick to the object, separating from the heavier salt. This happens because the charged object attracts the opposite charges in the pepper, lifting the flakes against gravity.
You can also try making your hair stand straight up by rubbing a balloon all over your head. The balloon pulls electrons from your hair, leaving every strand with the same positive charge. Since objects with the same charge repel each other, your individual hairs push away from their neighbors, creating a funny, floating effect.
What Happens When Charges Meet
Once a large enough charge has built up on an object, it cannot stay there forever. The built-up charge is always trying to find a path to return to a neutral, balanced state. This sudden movement of electrons to correct the charge imbalance is called an electric discharge. When you shuffle your feet on a carpet and then touch a metal doorknob, the electrons that built up on your body suddenly jump to the metal, causing the quick shock you feel.
The tiny spark and snap you hear result from the air heating up quickly as the electrons rush through it. On a much grander scale, this discharge is exactly what happens when lightning strikes. During a storm, clouds build up massive static charges, and when the difference between the cloud and the ground is too great, the electrons move instantly in a flash to restore balance.