Electrical Energy- static and current

electrons Are a small part of an atom They are found orbiting around the nucleus of atom They carry a negative charge When they move from atom to atom that is electricity

electricity Two forms: Static: When electrons build up on the surfaces of objects and then jump away =(zap!) Current: When electrons flow in a conductor (usually metal)

charge Is like a force that affects parts of atoms Things can have a positive charge, a negative charge, or be neutral Similar charges repel Unlike charges attract “opposites attract”

Static Electricty By rubbing objects together, electrons can build up on one object (think balloon activity!) The electrons are all alike, so they try to get away from each other as best as they can Provide them with a way out and they will take it! (John Travoltage!)

Positive / negative charges Objects with a negative charge have an excess of electrons on their surfaces Objects with a positive charge have less electrons on their surface

Conduction When charges can flow from one object to another They need to touch: conduction= contact Metals (like copper, gold) are good conductors

Current Electricity Series Circuits 1 directional flow 1 element stops working the entire circuit does not work Parallel Circuits 2 or more directional flow Circuit remains functional even without working elements

Energy Flow Cont’d Electrons (negative charges) flow in the opposite direction – from the negative terminal If a circuit is not a complete loop it will not work as intended No electrical connection is made and the current stops An incomplete loop is called an open circuit Electricity only flows through a closed circuit!

Energy Flow Energy that flows through a circuit is called a current or amperage, measured in amps “Pressure” of that energy flow is called voltage, measured in volts When hooked up to a battery the current flows out of the negative (-) end and around through the circuit back into the positive (+) end

More Energy Flow Resistance occurs when something extra is introduced into the circuit (i.e. light bulb). This is called a Load. More light bulbs = more resistance More resistance = less current = dimmer light produced

AC or DC? Alternating current Ex. power plant Direction of the current reverses; can easily change the voltage (with transformers) Direct current Ex. batteries, fuel cells, solar cells Current flows in one direction from negative terminal to positive terminal

Electricity Basics 3 basic units in electricity Voltage (V), measured in volts Current (I), measured in amps Resistance (r), measured in ohms Ohm’s Law: I = V / r Increasing voltage will make more current flow Decreasing resistance will also make more current flow