Electricity Active Physics

The Atom All matter is made up of atoms Atoms are made up of 3 types of particles protons, electrons and neutrons Protons have a + charge Electrons have a - charge Neutrons have no charge All matter is made up of atoms Atoms are made up of 3 types of particles protons, electrons and neutrons Protons have a + charge Electrons have a - charge Neutrons have no charge

What is a Charge? A charge is an electrical property of particles that causes them to attract and repel each other. Opposite charges attract each other Similar charges repel each other A charge is an electrical property of particles that causes them to attract and repel each other. Opposite charges attract each other Similar charges repel each other

Charged Particles Atoms can either be positively charged, negatively charged or neutral An atom is + if it has more protons than electrons An atom is - if it has more electrons than protons

Negative Atom Positive Atom

Electricity Review (take notes) All matter is made up of atoms Atoms are made up of + protons, - electrons and neutral neutrons Atoms with more protons than electrons are + Atoms with more electrons than protons are - Opposite charges attract and similar charges repel All matter is made up of atoms Atoms are made up of + protons, - electrons and neutral neutrons Atoms with more protons than electrons are + Atoms with more electrons than protons are - Opposite charges attract and similar charges repel

Electricity Protons and neutrons are in the center of an atom called the nucleus - they never move Electrons orbit around the nucleus and are able to jump or move from one atom to another Protons and neutrons are in the center of an atom called the nucleus - they never move Electrons orbit around the nucleus and are able to jump or move from one atom to another The movement of electrons from one atom to another is called ELECTRICITY

Electricity cont…. A steady flow of electricity is called an electric current A current will move along a path called a circuit A steady flow of electricity is called an electric current A current will move along a path called a circuit

Static Electricity When you walk across a carpet electrons move from the carpet to your shoes You and your shoes are now negatively charged When you reach for a doorknob those extra electrons jump from you to the door creating electricity and making a spark! When you walk across a carpet electrons move from the carpet to your shoes You and your shoes are now negatively charged When you reach for a doorknob those extra electrons jump from you to the door creating electricity and making a spark!

Current Electricity Current electricity flows when electrons are allowed to follow a complete path called a circuit. For example, a battery to a wire to a light bulb If any part of this path is broken the electrons can’t flow and the light won’t turn on! Current electricity flows when electrons are allowed to follow a complete path called a circuit. For example, a battery to a wire to a light bulb If any part of this path is broken the electrons can’t flow and the light won’t turn on!

Conductors and Insulators What do you remember about conductors and insulators?

Conductors allow an electric current to flow easily through them - this is why most electrical wire is made of metal Insulators do not allow electric current to flow easily through them - this is why the covering for wires are made of plastic What would happen without the plastic covering? Conductors allow an electric current to flow easily through them - this is why most electrical wire is made of metal Insulators do not allow electric current to flow easily through them - this is why the covering for wires are made of plastic What would happen without the plastic covering?

Electricity Review #2 (take notes) The movement of electrons from one atom to another is called electricity. A steady flow of electricity is called an electric current Current electricity occurs when electrons flow around a complete circuit Conductors allow electrons to flow - insulators do not allow electrons to flow Static electricity occurs when you transfer electrons from one object to another The movement of electrons from one atom to another is called electricity. A steady flow of electricity is called an electric current Current electricity occurs when electrons flow around a complete circuit Conductors allow electrons to flow - insulators do not allow electrons to flow Static electricity occurs when you transfer electrons from one object to another

More on Current Electricity The flow of electrons along a path is called an electric current This path is called an electric circuit The flow of electrons along a path is called an electric current This path is called an electric circuit Series Circuit  the electricity has only one path to follow Parallel Circuit  the electricity has more than one path to follow If there is a break in the circuit, which light bulb will still light?

Drawing Circuits - Symbols to Know Light bulb Battery Switch Resistor Light bulb Battery Switch Resistor

Series Circuit Parallel Circuit

Electricity Analogy

Current Imagine the current as a river or stream A large river carries a large amount of water A large current carries a large number of electrons Imagine the current as a river or stream A large river carries a large amount of water A large current carries a large number of electrons

Voltage Imagine the river ends in a waterfall The higher the waterfall, the higher the force of the water going over The higher the voltage, the higher the force that is pushing the electrons Imagine the river ends in a waterfall The higher the waterfall, the higher the force of the water going over The higher the voltage, the higher the force that is pushing the electrons

Resistance Now imagine the water encounters some rocks as it falls A lot of rocks will resist the movement of the water and remove energy from the water A circuit with high resistance will resist the flow of electrons and remove energy from the circuit Now imagine the water encounters some rocks as it falls A lot of rocks will resist the movement of the water and remove energy from the water A circuit with high resistance will resist the flow of electrons and remove energy from the circuit

Overview Current, Voltage & Resistance

Ohm’s Law Review (take notes) The current (I) in a circuit is measured in amps and is a measure of the number of electrons that are moving through the circuit The voltage (V) of the circuit is measured in volts and is a measure of the force that is pushing the electrons The resistance (R) of the circuit is measured in ohms and is a measure of the energy that is being removed from the circuit The current (I) in a circuit is measured in amps and is a measure of the number of electrons that are moving through the circuit The voltage (V) of the circuit is measured in volts and is a measure of the force that is pushing the electrons The resistance (R) of the circuit is measured in ohms and is a measure of the energy that is being removed from the circuit