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Electric charge is a property of matter. Static charges are caused by the movement of electrons, resulting in an imbalance of positive and negative charges. At first, a balloon and a glass rod each have balanced, neutral charges. Static charges are caused by the movement of electrons, resulting in an imbalance of positive and negative charges. When they touch, electrons move from the rod to the balloon. electric charge A property that allows one object to exert a force on another object without touching it. Electric charge can be positive or negative: positive charge is a property of the proton, while negative charge is a property of the electron. electric field An area surrounding a charged object, within which the object can exert a force on another object without touching it. Bell Fun 1-6-12 • Explain what you observed in procedure form when you rubbed a balloon on your hair and placed it on an object in the room. • Static Electricity: Charges build up, but do not flow. The buildup of electric charge in an object caused by the uneven distribution of charged particles. 3 Causes of static electricity: 1st Cause of Static Electricity 1. Friction: transfer of electrons from one object to another by rubbing. • Ex: clothes in a dryer/ rubbing balloon on hair. 2nd Cause of static electricity 2. Conduction: the transfer of electrons by direct contact. • Ex: touching a car door or someone and getting shocked! 3rd Cause of Static electricity 3. Induction: the movement of electrons to one part of an object caused by the electric field of another object. The buildup of a static charge in an object when the object is close to, but not touching, a charged object. Behaviors of Conductors/Insulators • Conductors: Electrons are loosely bound to the atom and electrical currents move freely through the wire. • Copper, aluminum, silver and iron. • Insulators: Electrons are bound tightly to atom and do not flow easily. • Rubber, glass, plastic, sand, wood. electric potential The amount of potential energy per unit charge that a static charge or electric current has. Electric potential is measured in volts, and is often called voltage. volt The unit of measurement for electric potential, which is equal to one joule per coulomb. The number of volts of an electric charge equals the charge’s voltage. Resistance The property of a material that determines how easily a charge can move through it. Resistance is measured in ohms. ohm The unit of measurement for electrical resistance. electric current A continuous flow of electric charge, which is measured in amperes. Ampere The unit of measurement of electric current, which is equal to one coulomb per second. The number of amps flowing through a circuit equals the circuit’s amperage. How is Electric Current Measured? • Electric current is measured in amperes, or amps. • Ohm's law states that current equals voltage divided by resistance. • Current Voltage Resistance Easy for Ohm’s Formula Grounding The creation of a harmless, low-resistance path—a ground—for electricity to follow. Grounding is an important electrical safety procedure. Circuit – complete path through which electric charges can flow. 1. circuit has a source of electrical energy. 2. circuits have devices that are run by electrical energy. 3. electric circuits are connected by conducing wires and a switch. electric cell A device that produces electric current using the chemical or physical properties of different materials. A battery consists of two or more cells linked together. Flow of electrons, energy source Superconductors – materials that have no resistance to electrical flow. NO LOSS OF ENERGY occurs in a superconductor. • Resistor: A resistor uses electrical energy or “resists” the flow of charge in an electrical circuit. Light bulb, any electrical appliance. • Series Circuit: Only one path for the current to take. • Pro: Simple and cheap to make • Cons: 1. If one light goes out, they all do • Lights become dimmer as you add more bulbs (less current and more resistance!) Parallel Circuit: Several paths for the current to take. Pro: Individual bulbs can be turned on and off without affecting each other. Ex: Household circuits