6.1 Electric Charge and Static Electricity Chapter 6 – Electricity 6.1 Electric Charge and Static Electricity

I. Essential Question: How do charges interact and build up?

II. Key Vocabulary Electric force: the force between charged objects. Electric field: a region around a charged object where the electric force is exerted on other objects. Static Electricity: the buildup of charges. Conservation of charge: charges are neither created now destroyed.

II. Key Vocabulary Friction: when two objects rub against each other. Conduction: when two objects have direct contact. Induction: when an object becomes charged without touching a charged object. Polarization: when all of the charges particles go to one side of the object. Static discharge: the loss of static electricity and return to a neutral state.

III. Key Concepts Protons are positive, electrons are negative – when they come close to one another, they are attracted to each other. Particles with similar charges repel each other. Electric fields and forces get weaker with greater distance.

III. Key Concepts In an electric field, the field lines always point away from positive charges and toward negative charges. Most objects have no charge, but can become charged by losing or gaining an electron. If an object loses electrons, it becomes positive; if it gains electrons, it becomes negative.

III. Key Concepts Charging by friction: transfer of electrons from one uncharged object to another by rubbing them together. Charging by conduction: transfer of electrons from one object to another by direct contact. Electrons transfer from the object with a negative charge to the object with a positive charge.

III. Key Concepts Charging by induction: transfer of electrons without touching; if a metal comes near a negative object, the electrons will repel and the protons will all move toward the end of the metal object closest to the charged object. Charging by polarization: individual atoms in an object have charged ends that are attracted to charged objects.

III. Key Concepts Charged particles eventually lose/gain electrons from the air to balance out. Static discharge often produces a spark, especially during the winter because objects hold on to charges better in dry air.

III. Key Concepts Lightning formation: Water droplets in clouds become charged. Electrons move to areas of positive charge (clouds become polarized). This causes the ground to also become polarized. The electrons at the bottom of the cloud are attracted to the protons at the surface, and a large spark is formed.

IV. Exploration

V. Understanding and Applying

Chapter 6 – Electricity 6.2 Electric Current

I. Essential Question: How is Electric Current made? How do conductors differ from insulators?

II. Key Vocabulary Electric current: the continuous flow of electric charges through a material. Electric circuits: a complete, unbroken path that charges can flow through. Conductors: a material through which charge can flow easily. Insulators: materials that do not allow charges to flow. Semiconductors: materials that sometimes act like conductors and other times like insulators.

III. Key Concepts Electric current is measured in amperes, of amps (A). The number of amps is the amount of charge flowing past a given point each second. If an electric circuit is broken, the charge stops flowing through the material.

III. Key Concepts Conductors – most metals Insulators – rubber, plastic, glass, wood, etc. The atoms in conductors have loosely bound electrons that move more freely than insulators.

IV. Exploration

V. Understanding and Applying

Chapter 4 – Electricity 4.2 Electric Current

I. Essential Question: How affects current flow? What is Ohm’s Law?

II. Key Vocabulary Voltage: the difference in electric potential energy per charge between two points in a circuit. Resistance: the measure of how difficult it is for charges to flow through an object.

III. Key Concepts Potential energy from a battery gets turned into different energy forms. Voltage energy causes charges to keep flowing through a material. The greater resistance, the less current there is per voltage.

III. Key Concepts Resistance is measured in ohms. If more than one path is available, an object will flow through the path with least resistance. Current flows better in: Wide wires Short wires Conductors Lower temps

IV. Exploration

V. Understanding and Applying

Chapter 6 – Electricity 6.3 Electric Circuits

I. Essential Question: What is a circuit made of? What is Ohm’s Law (review)?

II. Key Vocabulary Ohm’s Law: resistance in a circuit is equal to voltage divided by the current. Series circuit: a circuit that only has one path. Parallel circuit: a circuit that has more than one path.

III. Key Concepts Circuits have the following parts: Energy source, such as a battery. Resistors (transform electrical energy into other forms) Conducting wires to carry the current A switch to turn the circuit on and off

III. Key Concepts Series Circuit: Has one path If one light goes out, all of the lights go out. Current decreases as more lights are added, so the lights get dimmer.

III. Key Concepts Parallel Circuit: Has more than one path. If one light goes out, the others remain lit. The brightness of the bulbs stays the same regardless of how many lights are attached.

IV. Exploration

V. Understanding and Applying

6.4 Electric Power and Current Chapter 6 – Electricity 6.4 Electric Power and Current

I. Essential Question: How can you calculate electric power? What are some safety precautions with electricity?

II. Key Vocabulary Power: the rate at which energy is converted from one form to another. Short circuit: a connection that allows current to take the path of least resistance. Third prong: part of most electrical plugs. Grounded: when an electrical circuit is connected to the ground. Fuse: device that melts when it is too hot. Circuit breaker: device that turns off when it is too hot.

III. Key Concepts Power is measured in Watts (or kilowatts) and can be found by multiplying the voltage by the current. Lights that use up energy more quickly (brighter lights) have a higher power. The total amount of energy used is equal to the power of the appliance multiplied by the amount of time the appliance is used. Energy = power x time

III. Key Concepts A frayed wire is an example of a short circuit; there is a path with lower resistance than the actual circuit. Third prongs that are grounded help absorb any extra shock, protecting buildings and people. Fuses melt when they become too hot, causing the circuit to become disconnected. Circuit breakers bend away from circuits when they become too hot, also disconnecting the circuit.

IV. Exploration

V. Understanding and Applying