1. Statics, Coulomb Law, and current electricity. Friday, February 12, 2016

2. Friday, 2/12  How are the forces of gravity and the forces that keep the planets rotating around the sun similar? How are they different? Upcoming dates:  Friday, 2/12 – Statics quiz – moved to Wednesday, 2/17  Wednesday, 2/17 – Series circuit quiz – moved to Friday, 2/19  Friday, 2/19 – Parallel circuit quiz – moved to Tuesday, 2/23  Tuesday, 2/23 – Circuit design due  Thursday, 2/25 – Unit quiz  Monday, 2/29 – Electricity Test and missing work deadline  Friday, 3/4 – Magnetism quiz  Friday, 3/4 – 3NWS Extra credit due by 4:00 PM  Thursday, 3/10 – Waves Quiz  Friday, 3/11 – End of the 3NWS

3. Thursday, 2/11 Use your video notes to complete the following sentences about static electricity: 1. Static electricity is also know as electricity at rest 2. Static electricity produces electric charges that can be confined to an object.

4. Induction/Conduction guiding questions (6 minutes)  What circumstances must be present for conduction to take place?  What type of charge is transferred during the process of conduction ?  Draw the diagram that demonstrates conduction.  What circumstances must be present for induction to take place?  What type of charge is transferred during the process of induction ?  Draw the diagram that demonstrates induction.

5. Coulomb’s Law guiding questions (6 minutes  Explain the affect the value of the charges and and the distance of the charges has on the electrical force.  Write Coulomb’s equation and label the variables (include units).  How do you convert micro coulomb’s ( μC) to coulombs  What does the value of F electric tell you about the charges attraction/repulsion?  Set up the G and U for example #1.

6. Practice

7. Article – Shocking idea  Number your paragraphs (there should be 8).  Highlight the following words:  Electricity (all versions such as electric)  Shock  Charge  Static  Positive  Negative  Neutral  Friction  Circle words you don’t know the meaning of.  Underline statements about static electricity.

9. Electric Current  The continuous flow of electrons through a conducting metal.

10. Alternating Current  Flow of current that periodically changes direction  Produced in power plants  Current from a wall outlet changes direction 120 times per second

11. Direct Current  The flow of current in one consistent direction  Examples  Batteries  Solar cells  Current from a battery travels from the positive terminal to the negative terminal.

12. Common Language

13. Note Taking Guide QuantitySymbolDefinitionUnitMeasuring Device voltage current resistance

14. Voltage  Voltage (V) (also know as Potential Difference) can be thought of as the force pushing electric charges along a conductor. Voltage between two points creates an electric field.  Measured in Volts (V)

15. Voltmeter a device that measures electric potential difference, must be connected in parallel

16. Current  Electric current (I) is the movement of electric charge in a conductor.  Measured in Amps (A)

17. Ammeter a device that measures current attached in series

18. Resistance  Resistance (R) is a measure of how difficult it is to push the charges along.  The energy is transformed at the resistor (potential energy is converted).  Examples: light bulb, charging your phone, making coffee, etc.  Measured in Ohms ( 

19. Note Taking Guide QuantitySymbolDefinitionUnitMeasuring Device voltageVEnergy in the circuitVoltsVoltmeter currentIRate of flowAmpsAmmeter resistanceROpposes currentOhmsΩOhmmeter

20. Ohm ’ s Law  Ohm's Law analyzes the relationship between voltage and current in an ideal conductor.  Ohm's Law is given by:  V = I * R

21. Example A flashlight that is powered by 3 volts and uses a bulb with a resistance of 60 ohms. What is the current flowing through the circuit?

22. Practice

23. Electrical Circuit Terminology  Circuit – a path that allows electricity to flow  Circuit diagram – a simplified representation of an electrical circuit that shows only the electrical connections of elements in a circuit.  We will study two types of circuits:  Series circuit  Parallel circuit

25. Cool Down  What is the difference between static and current electricity?

26. Resistors can be connected in series; that is, the current flows through them one after another. Series Circuits

27. Kirchhoff’s Rules Loop Rule: The sum of the potential differences (voltage) around any closed circuit loop is zero.

28. Kirchhoff’s Rules Loop Rule: The sum of the potential differences (voltage) around any closed circuit loop is zero.

29. SeriesSeries Circuit Series 1. total resistance is the sum of the separate resistors separate resistors R T = R 1 + R 2 + R 3 +... 2. current is the same through each resistor I T = I 1 = I 2 = I 3 =... 3. total potential difference is the sum of each V T = V 1 + V 2 + V 3 +... In other words, in a series circuit, resistance and voltage add, but current stays the same.

30. Series Circuit Example