1. Integrated Science I

3. Electrical conductors – a material that allows electrons to flow easily through it Ex) gold, silver, copper, etc. Electrical insulators – a material that does not allow electrons to flow easily through it Ex) plastic, rubber, wood, etc. A complete conducting loop is needed for an electrical circuit to work correctly. There are 2 types of circuits: Parallel – each device is placed in its own separate branch. Series – a device placed in a single loop

4. An electric circuit is a path in which electrons from a voltage or current source flow Voltage or current source could be a battery Flow freely in conductors Do not flow freely in insulators Electric current flows in a closed path called an electric circuit and only flows in one direction

5. Household circuits are wired in parallel. Why? Single power source supplying all lights and appliances with the same voltage If one of the lights burns out, current can still flow through the rest of the house Christmas tree lights are typically wired in series This is why your whole strand goes out

6. Series CircuitParallel Circuit

7. For protection, household circuits contain: Circuit Breakers Contains a piece of metal that bends when it gets hot Fuses Contains a small piece of metal that melts if the current becomes too high When it melts, it causes a break in the circuit, stopping the flow of current To fix, you must replace the blown fuse with a new one

8. Electric current – is the rate at which positive charge flows in a circuit It measures how fast the electrons are moving in the circuit Flows from high to low (think of it like water pressure) Measured in amperes (A) Equals 1 coulomb of charge per second (C/s)

9. A resistor opposes the rate of charge flow in the circuit They are not a bad thing! Ex) Light bulb, toaster, ANYTHING that takes electricity to run Resistance is a measure of "how hard" it is to "push" electricity through a circuit Unit of resistance is the ohm ( Ω ) If we increase the resistance, the voltage goes down Because electrons cannot flow as easily If we decrease the resistance, the voltage goes up Because electrons can flow easily Batteries are energy sources and resistors are energy stoppers in circuits

10. Electrical Power – the rate at which electrical energy is converted to another form of energy SI Unit: Watt (W) Term for 1,000 units = kilowatt (kW) In this example, electrical power is converted to light energy in the light bulb. The light bulb acts as a resistor

11. A chemical reaction that separates positive and negative sides of the battery The separation is what causes the electrons to flow in the circuit Electrons then transfer energy to other objects and transform electrical energy into other forms: Light Sound Heat Current continues to flow, even after the electrons transfer their energy

12. V = Volt Definition: The SI unit of electromotive force, the difference of potential that would drive one ampere of current against one ohm resistance Voltage is also known as potential difference Measured with a voltage meter

13. The voltage difference between the two holes in a wall socket is typically 120 volts

14. Q: If electrons are never “used up” in a circuit, why do batteries go dead? A: Batteries go dead because the electrons are converted in resistors to other types of energy (light, sound, heat, etc.) Q: Do batteries supply all of the electrons in a circuit? A: NO! Electrons are in all of the circuit. The battery provides the “push” for the electrons

15. Important SI Units: Current = amperes (A) Voltage = volts (V) Resistance = ohms ( Ω ) Types of Circuits: Series = 1 continuous loop Parallel = branches Power source supplies the electrons in the circuit: Resistors then transform electrical energy to sound, light, heat, etc. Relationship between current, resistance, and voltage: If we increase the voltage, the current goes up If we increase the resistance, the current goes down.