Electricity 101 Electricity is the flow of electrical charge (electrons) Electricity is a secondary source (made from primary sources: coal, fuel, natural gas, oil…) Electricity is one of the most widely used forms of energy.

Electricity 101 We tend to take electricity for granted, but electricity helps us in many ways Cooling/heating our homes Lighting our homes and school Powering television and appliances Charges our cell phones

Electricity 101 The flow of electrons through a closed circuit.

Two types of electricity CURRENT STATIC

Static Electricity

Static Electricity If you have ever been shocked, you have experienced static electricity. Static electricity is the accumulation of excess electric charges on an object.

Static Electricity There is a rule associated with static electricity Opposite Charges Attract; Like Charges Repel

What Causes Static Electricity? Most objects have a neutral charge (equal numbers of protons and electrons) When one object rubs up against another object, electrons are transferred between the two objects and both objects become charged!

Building Up Charge When an object becomes charged, the charge is neither created or destroyed (Law of Conservation of Charge) Charge can only be transferred!!!

Examples of Static Electricity Getting shocked when touching a metal door knob

Examples of Static Electricity Hair standing up when rubbed with a balloon

Examples of Static Electricity Clothes sticking together in the dryer Build up of charges through conduction- when objects touch

When a charged object gets near a conductor Lightning When a charged object gets near a conductor Objects can transfer electric charge (induction) When clouds form, they rub up against each other and become charged, opposite charges attract from the ground to the sky.

Static Electricity Explained Click for Video! https://www.youtube.com/watch?v=yc2-363MIQs

Friction Conduction Induction Charges that results by objects rubbing against each other. Conduction Charges that result by direct contact. Induction Charges that result by objects that do not come into contact.

Current Electricity

Current Electricity Current electricity is the flow of electrons through a circuit. A circuit is a complete, closed pathway for electricity. Conductors allow electricity to flow easily. (Ex. Copper)

Types of Current Electricity Generators produce electric current as a coil of wire moves through a magnetic field. As the coil rotates, the direction of the electric flow constantly reverses direction. This is called an alternating current (AC). AC is used to deliver power to houses, office buildings, etc.

Most home appliances run on AC current. Examples of AC Current Most home appliances run on AC current.

Alternating Current

Types of Current Electricity Batteries can produce an electric current from chemical reactions. Electrons are produced from the chemical reaction inside the battery. Batteries produce direct current (DC) which flows in only one direction.

Direct Current

How do we get our electricity? Research: Have you ever wondered why the lights turn on with just the flick of a switch? In groups of 2 or 3, research where our electricity comes from. Create an illustration/diagram that shows the path of electricity from its original source to a device that is powered by electricity. Be prepared to share with your classmates! 

How do we get our electricity? 1- Nuclear power plant, 2-Turbines, 3-Generator, 4-electricity is held in transformers, 5-electricity travels to homes/businesses via powerlines 5

Measuring Electricity

Measuring Electricity Electricity can be measured a number of ways. Current Resistance Voltage Click for Video! https://www.youtube.com/watch?v=8gvJzrjwjds

Voltage Current Resistance Task: Use the illustration to create your own descriptions for the terms: Voltage Current Resistance resistance current voltage Clipart Credits: http://www.sengpielaudio.com/calculator-ohmslaw.htm

Current Electric current is very similar to a flowing river. With electricity, current (I) is a measure of the amount of electrons transferred over a period of time. The electrons move through conductive materials such as copper wire Amps is the unit for current

Voltage Voltage is the force that causes charges to flow. (Think about it as pressure) Unit: volts

Resistance Resistance is the tendency for a material to oppose the flow of electrons. Unit: ohms Ω Conductors have less resistance than insulators Ex. Copper Resistance will oppose electron flow through a conductor

Ohm’s Law A formula used to measure resistance, current and/or voltage. Resistance is directly proportional to voltage & inversely proportional to current Resistance = voltage/current Current = voltage/resistance Voltage = current x resistance V R I

Units Voltage = Volts Resistance= Ohms Current = amps

Flowing Electrons Ohm’s Law: Example: What is the resistance of a circuit if the current is 4 amps and the voltage is 12 volts? Answer: R=V/I = 12 V / 4 amps = 3 Ohms

Ohm’s Law Practice Complete the Ohm’s Law practice problems.

PARALELL VS. SERIES

Series Circuit Only one path is provided for electric current.

Series Circuit In a series circuit, the voltage is divided amongst the load (assuming each bulb is the same wattage) 60 V 60 V 120 V Answer: If a third bulb is added, the voltage would be distributed equally. Therefore, each bulb would receive a voltage of 40 V. If a fourth bulb were added, the voltage for each bulb would be What if a third bulb was added? A fourth?

Parallel Circuit Alternate paths or branches are provided for electric current.

Parallel Circuit In a parallel circuit, each load (bulb) gets the full voltage. 120 V 120 V 120 V 120 V Answer: If a fourth bulb was added, it would get 120 V. What if a fourth bulb was added?

Series and Parallel Circuit Practice Complete the series and parallel circuits worksheet.