Science Test electricity

controlled flow of electrons

Static: electrons gather in one place and move randomly in all directions Current: controlled flow of electrons

Load: part of electric circuit that converts electrical energy into other forms of usable energy Energy source: where the electrical energy comes from Switch: device that controls flow of electrons by breaking or completing the circuit Electrical wires: pathway for electrons to travel

An accidental connection between two points in a circuit

Electrocution Electrical shock Fires

Portable device that converts chemical energy into electrical energy Chemical reaction creates a positive and negative end

Primary cell: uses non-reversible chemical, so it cannot be recharged Secondary cell: uses a reversible chemical reaction and can be recharged

Direct current: Electrons flow in one direction through a circuit Produced by an electric cell (battery) to power electric device Alternating current: Electrons move back and forth, changing directions Produced by generators More efficient method of distributing electrical energy over long distances Found in wall outlets and lights

Converts kinetic energy into electrical energy External energy source spins the turbine which turns the coil of wire Since the coil is moving near a magnet, the magnetic force forces electrons to move through the wire Components: turbine, wire coil, magnet

Water: Hydroelectricity Tidal Dam: Water stored high flows down to spin turbines. Tidal: Tides move turbines to generate power Disrupts aquatic ecosystems Lowers greenhouse emissions renewable

Radioactive Fossil fuels Nuclear: Radioactive heat makes steam to generate power. Fossil fuels: Burning coal, oil, or gas makes steam to spin turbines. Radioactive: Efficient, low carbon, but risky waste. Fossil: Cheap, high emissions, warms planet. nonrenewable

Biomass Geothermal Biomass: Burning biomass makes steam to spin turbines. Geothermal: Earth’s heat makes steam to generate power. Biomass: Available fuel, causes air pollution. Geothermal: Clean, but location-limited. renewable

Wind rotates turbine Low operating cost Inconsistent source of energy (not always windy) Renewable

Light from sun is converted to electric energy using photovoltaic cell Light from sun is converted to electric energy using photovoltaic cell Renewable

energy =joules

energy, power, time (in seconds)

Efficiency is a measure of how much useful energy gets produced by a device compared to the amount of energy supplied to it

The shorter end is negative Longer end is positive

Electrons flow from the negative terminal to the positive terminal As they move they lose potential energy

For any device to operate, it requires a steady flow of electrons Electric current (I) is the rate of electron flow past a specific point in the circuit Current is measured in amperes (A)

electricution

Very large currents can damage electrical devices Fuses are connected in series with circuits leading to the electrical devices If there is too much current through the fuse, it is triggered (flips) and acting like a switch Interrupts the circuit so that no current flows through

An ammeter is a device used to measure current flowing through different loads of the circuit An Ammeter must be hooked up in series with other components in a circuit so that electrons flow through it

Electric charge is the quantity of electrons - measured in Coulombs ©