Unit 7: Electrostatics, Electricity, & Circuits

1. Unit 7: Electrostatics, Electricity, & Circuits

2. Warm Up 3/19 To deter burglars, you leave on your front porch light at all times! If your fixture contains a 60W light bulb and your electricity company charges 8 cents per kW-hr, how much does this cost you per month? (assume 30 days) http://www.siliconvalleypower.com/for-residents/save-energy/appliance-energy-use-chart

3. Academic – Tuesday 3/19 • Warm up: On board (5 Min) • Physics Fun Fact (SpaceX Crew Dragon) • Ohm’s Law/Power Quiz • Continue Circuits • Circuit Diagram Activity • Circuits Formative (Due next class) • Unit 7 Test – 3/27/19

4. Conceptual – Wednesday 3/20 • Physics Fun Fact (Bill Nye Part 2) • Ohm’s Law/Power Quiz • Continue Circuits • Review Circtuit Diagram Activity • Simplifying Circuits • Unit 7 Test – 3/28

5. https://finance.yahoo.com/news/spacex-proves-apos-ready-return-131800594.htmlhttps://finance.yahoo.com/news/spacex-proves-apos-ready-return-131800594.html https://www.spacex.com/dragon https://www.mirror.co.uk/science/nasa-return-moon-2028-time-14122138 https://www.youtube.com/watch?v=RqLNIBAroGY https://www.dogonews.com/2019/3/11/spacexs-crew-dragon-completes-historic-test-mission-to-the-international-space-station

6. Tesla Coil https://waveguide.blog/history-tesla-coil-geometries/ - History of the Tesla Coil https://www.youtube.com/watch?v=Snibt3CNqBA https://www.iflscience.com/physics/band-use-tesla-coils-play-music/ https://www.youtube.com/watch?v=gL7qMiRBRNs

7. Conceptual – Friday 3/8 Unit 6 Retake through 3/11 • Physics Fun Fact https://www.youtube.com/watch?v=sy05B32XTYYElectrostatics HW Review • Turn in HW • Electrostatics Quiz! • Tesla v. Edison: The Current War

8. https://joeforamerica.com/2019/01/kim-seal-doctor-astronaut/?fbclid=IwAR22sXATTNrQS4iec3oT5zguoCZzi8fhGsDd6J7kdEZiWrQaGNVjmoensIAhttps://joeforamerica.com/2019/01/kim-seal-doctor-astronaut/?fbclid=IwAR22sXATTNrQS4iec3oT5zguoCZzi8fhGsDd6J7kdEZiWrQaGNVjmoensIA • https://www.youtube.com/watch?v=2T1Qcs4VKtk

9. Part 1 – Electrostatics Electrostatics: The study of stationary electric charges and electric fields

10. The origin of electricity • Electrical nature of matter in atomic structure: • Proton: Positive charge • Neutron: No charge • Electron: Negative charge Protons: +e Electrons: -e e = 1.602 x 10-19C Charge: Variable – q Si Unit – Coulomb (C)

11. Conservation of Charge

12. Conductors and Insulators • Conductors – Materials that allow unrestricted flow of electrons. • Insulators – Materials that don’t allow good flow of electrons.

13. Charging by Contact and induction Note: Electrons travel from -Ions to +Ions • Charging by Contact – Physical contact is made to transfer positive/negative charges. • Charging by Induction – Positive/negative charges are transferred to a conductive surface without physical contact.

14. https://www.youtube.com/watch?v=9OVtk6G2TnQ&list=LLTvzgV7GP8jI_ZFsE7IyDoA&index=4&t=0shttps://www.youtube.com/watch?v=9OVtk6G2TnQ&list=LLTvzgV7GP8jI_ZFsE7IyDoA&index=4&t=0s How do batteries Work? A chemical reaction results in an excess of electrons. When a circuit is closed (plugged in), the excess electrons flow to the positive terminal. This creates voltage to power a device. (More on voltage later) https://elemains.com/basics-of-electricity-charge-voltage-current/ https://www.livescience.com/50657-how-batteries-work.html http://mentalfloss.com/article/12325/why-arent-there-b-batteries

15. Coulomb’s Law • The closer two charges are, the stronger the force between them. • k – Coulomb’s Constant • Similar structure to Newton’s Universal Law of Gravitation • Inverse Square Law

17. Electric Fields • Electric Fields – A vector field around an electric charge that exerts force on other charges • Conceptual Physics Textbook page 519 • Below: PHET Electric Field Simulation https://phet.colorado.edu/sims/html/charges-and-fields/latest/charges-and-fields_en.html

18. Electric Fields (E) • E represents electric fields • F is the Electrostatic Force • q is the charge • Often referred to as the Strength of an Electric Field Unit: [N/C] Newton/Coulomb

19. Electric Field Lines Positive: Away Negative: Towards

20. Electric Potential • Charges acquire electrical potential energy as they near another charge • See Figure 33.11 (Page 524) • Voltage: The amount of electrical potential energy per charge. Unit: Joule/Coulomb OR Volt

21. Voltage Facts • AA Battery: 1.5V • 9 Volt Battery • Car Battery: 12V • Wall sockets in The United States: 120V • Power Lines: 100kV-700kV

22. Capacitors • Capacitors store electrical energy in an electric field. • Found in common household items: keyboard, phones, computers, etc. • Positive and negative charges build up on parallel plates.

23. Van de Graaff Generator

24. Part 2 – Circuits

25. Electric Current (I) • The rate of flow of electricity • Current is represented by Variable: I • SI Unit: Ampere [A]

26. Direct & Alternating Current • Direct Current (DC): When charges flow in one direction. • Found in cars • Alternating Current (AC): When the direction of charges reverses periodically. • Found in homes

27. Resistance (R) • Resistance: The opposition to the flow of electric current • Example: • Metals (good conductors) have low resistance • Rubber (good insulator) has a high resistance • SI Unit: Ohms [Ω]  Greek letter Omega In the above circuit diagram, R1, R2, & R3 represent resistors

28. Resistors Used in circuits to: • Reduce current flow • Adjust signal levels • Divide voltage

31. Electric Power (P) • Represented by Variable: P • SI Unit: Watt [W] • The rate at which electrical energy is transferred by an electric circuit.

32. Series Circuits • Electricity flows through one path • The same current flows through the entire circuit • Voltage drops across resistors

33. Parallel Circuits • Electricity flows through 2+ paths • The same voltage flows through the entire circuit • Current drops across resistors

35. Resistance in Series & Parallel Circuits • Use the following equations to determine the total resistance in a circuit.