Current electricity

Learning goals We are learning the difference between: potential difference current resistance.

Potential difference

Potential difference potential energy: the energy stored in an object each electron has potential energy

Potential difference battery: chemical potential energy in the electrolyte in its electrochemical cells chemicals in electrolyte react with electrodes causes difference in amount of electrons between 2 terminals one terminal mainly negative charges other terminal mainly positive charges negative charges = electrons, so can move attracted to positive charges at positive terminal

Potential difference conductor (copper wire) connected to both terminals electrons flow from negative to positive terminal difference in electrical potential energy between two points in a circuit is called the potential difference or voltage (V) this difference causes current to flow in a closed circuit the higher the potential difference in a circuit, the greater the potential energy of each electron

Measuring potential difference measured with a voltmeter unit is the volt (V)

current

Electric current a measure of the amount of electric charge that passes by a point in an electrical circuit each second as long as battery continues to separate charges on its terminals, electrons continue to flow waterfall

Measuring current measured using an ammeter unit of electric current is the ampere (A) 1A = 6 200 000 000 000 000 000 electrons are flowing every second

Electric Current at Home Houses have safeguards installed in case too much current is being used. Fuses (older homes) vs Circuit breakers (newer homes) Circuit breakers are switches which turn off if too much current exists. Most homes have a total of 100-200A of electricity entering from their providers.

The Human Body The human body has it’s own electrical signals that exist naturally. Even small electrical shocks to the system are dangerous: 0.001A: Small tingling sensation 0.05-0.15A: Can cause muscles to contract 1-4.3A: Can stop your heart if passed through chest. An outlet that powers a computer can deliver 15A of current.

resistance

resistance the degree to which a substance opposes the flow of electric current though it measured in ohms (Ω) measured using an ohmmeter

resistors any material that can slow current flow used to control current or potential difference in a circuit converts potential energy to another form of energy

examples

4 Factors that Affect Resistance Type of Material: Insulator vs. conductor. Cross-sectional area: The larger the diameter, the less resistance. Length: The shorter the length, the less resistance. Temperature: The colder the wire, the less resistance.

Learning goals We are learning the difference between: potential difference current resistance.

Please complete What is another name for stored energy? How is an apple falling from a tree like the potential difference in a battery? What does potential difference measure? What is another name for potential difference? What is electric current? What does resistance refer to in terms of electron flow?

Please Complete P557 #1,4 P561 #2 P566 #2,3,5,6,7