1. Unit 8 - Electricity

2. Electricity Static Electricity: Electricity at rest Unequal + and - charges Electric Current: The flow of electric charge Electric current carries energy

3. Current Does the work Measure current using an ammeter Types of current: Alternating (AC): direction of current goes back and forth Example: household current is AC (60 Hz) Direct (DC): current flows in one direction. Example: battery

4. Electrical Conductivity Conductors- loosely bound electrons allow current to pass metals Insulators- tightly bound electrons block current nonmetals, plastics, rubber Semiconductors- moderate ability to conduct current Computer chips, LED’s, some lasers

5. How does charge flow? Voltage-the push behind the current! Electric charge flows from high energy (voltage) to lower energy. Voltage is measured using a voltmeter Voltage is reduced when energy is used. Supplies energy to make charges flow. Voltage is also referred to as potential difference

6. Resistance Measures how easily charges flow in a material Factors that affect resistance Thickness Thicker wire has a lower resistance Length Longer wire has more resistance

7. Ohm’s Law V = IR Voltage Unit: Volts (V) Symbol: V Current Unit: Amps (A) Symbol: I Resistance Unit: Ohms (Ω) Symbol: R