Charges and Electricity

Atoms, the basic building blocks of matter, are made of three basic components: protons, neutrons and electrons. The protons and neutrons cluster together to form the nucleus, the central part of the atom, and the orbit about the nucleus. Protons and electrons both carry an electrical charge. The charges they carry are opposite to each other; protons carry a electrical charge while electrons carry a negative electrical charge. Neutrons are charged - they carry no charge at all.

Electricity is the movement of charged particles, usually electrons, from one place to another. Materials that electricity can move through easily are called conductors. Most metals, such as iron, copper and , are good of electricity. Other materials, such as rubber, wood and glass, block the flow of electricity. Materials which the flow of electricity are called insulators. Electrical cords are usually made with both conductors and . Electricity flows through a in the center of the cord. A layer of insulation the conductor and the electricity from 'leaking' out.

Objects usually have equal numbers of positive and negative charges, but it isn't too hard to temporarily create an imbalance. One way scientists can create an imbalance is with a machine called a generator. It creates a large static charge by placing electrons on a metal dome using a motor and a big rubber band. Since like charges , the electrons push away from each other as they collect on the dome. Eventually, too many electrons are placed on the dome and they leap off, creating a spark that looks like a bolt of lightning.

Have you ever received a after having walked across a carpet? This shock was caused by extra electrons you collected while walking across the carpet. Your body became like the dome of the Van de Graaff generator, full of extra electrons looking for a way to get away. The path back to the carpet was blocked by the you were wearing, but they were able to move through your hand and into the object that you touched, causing the shock. So, the next time you shuffle across a carpet and shock your friend on the ear, tell them you were just trying to be a Van de Graaff generator!