1 / 48

Unit D: Electrical Principles

Unit D: Electrical Principles. Topic 1: Transfer and Storage of Electrical Energy. I. Review. What is electricity?. Is the energy of charged particles. Is when electrons are moved. Remember: Electrons are the outer particle of an atom. I. Review.

nalani
Download Presentation

Unit D: Electrical Principles

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Unit D: Electrical Principles Topic 1: Transfer and Storage of Electrical Energy

  2. I. Review • What is electricity? • Is the energy of charged particles • Is when electrons are moved Remember: Electrons are the outer particle of an atom

  3. I. Review • All matter is made of particles; Particles are atoms • Atoms are made of 3 sub-atomic particles: • Neutrons – neutral (0) particles • Protons – positive (+) particles • Electrons – negative (-) particles

  4. I. Review • Draw an atom!

  5. I. Review • Atoms are neutral – this means : # of protons = # of electrons • Being charged means having unequal protons and neutrons • +++ - - - - • + - +- - • - - - - -++ • Easiest method of charging, is through friction!!!

  6. II. Static electricity A. Laws of Electrical Charge • Opposite charges attract (+ and – will attract) • Like charges repel (ex. + and + will repel)

  7. Activity: Charge It To witness the action of uncharged/ charged objects on each other.  Remove charges from objects by running through your hand  Charge objects by running through paper towel or fur

  8. Activity : Charge It

  9. I. Static electricity • Definition: The state of having unequal number of protons and electrons ; is an UNMOVING charge • “static” means not moving; • charge DOES NOT flow constantly (vs. current electricity where charges are flowing)

  10. I. Static electricity A. Charge Separation • Occurs when a charged object is brought close to a neutral object • The same charges will repel, causing the opposite charges to attract

  11. Ex. Why a balloon (-) rubbed on your head sticks to the wall - DRAW!

  12. B. Electrical Discharge • Although static electricity does not move, it is “discharged” • Is the process of built up electrons transferring to other objects (Shocked!) Ex. lightning Electric eel Simulation

  13. Electric eels work to kill or stun prey by using electrical discharge of static electricity

  14. B. Electrical Discharge • Discharging makes the charges between objects equal • [Draw objects : Before / After ]

  15. B. Electrical Discharge • Grounding – a method of discharging an object • Done by connecting object with a wire to the Earth (it can absorb lots of electrons)

  16. C. Van DerGraff Generators • Used to study electrical discharges • Electrons build up on the outside sphere through friction -> the electrons seek to be discharged

  17. What is the difference between current electricity and static electricity? • Current electricity is a flow of electrons • Static electricity is a build-up of charges (+ or -)

  18. A. Circuit • Is a path of electron flow • Usually includes: • source (battery) • conductor (wire) • load (lamp or device) • switch (opens or closes a circuit) • Must be complete /closed for electricity to flow

  19. Sidenote: • Microcircuits –small circuits with low voltage and current. Where have you seen these parts before?

  20. Circuit symbols: wire lamp switch resistor - + Cell (battery)

  21. A. Circuits • Schematic diagrams – a neat representation of a circuit using circuit symbols

  22. B. Terms of Current Electricity • Conductors– materials which allow the flow of electrons (ex. Metals, water) • Insulators – materials which prevent (resist) the flow of electrons (ex. Plastic) • Load – a device which converts electrical energy to other forms of energy • Ex. Lamp, Radio, Motor

  23. B. Terms of Current Electricity

  24. B. Terms of Current Electricity • Examples: 1. What is the difference between 1.0A and 3.0A? 2. What is the difference between 1.5V and 9.0V? 3. What is the difference between 2.0 and 6.0 ?

  25. Video • How could the following picture be a metaphor for: • current • voltage • resistance

  26. B. Modeling Electricity Ex. Waterfalls Current – how quickly the water is flowing down the waterfall Resistance – how many rocks are in the stream bed, preventing the flow of water Voltage – the height of the waterfall (how much energy the water has)

  27. C. Cells and Batteries • Cells and batteries create current electricity in a circuit >Create the electron flow

  28. C. Cells and Batteries I. Basic Terms • Electrochemical Cell – a device that transforms chemical energy into electrical energy • Ex. AA, AAA – all 1.5V “batteries” are actually cells

  29. I. Basic Terms • Batteries –multiple cells joined together to create a larger voltage

  30. ACTIVITY: Cell Vs. Battery • Predict the voltage of each of the following: Remember: 1 cell = 1.5V

  31. I. Basic Terms Dry cells – when the electrolyte is a paste Wet cells- when the electrolyte is a solution

  32. I. Basic Terms Primary cells – cells that cannot be recharged Ex. Manganese-oxide alkaline batteries Secondary cells – cells that can be recharged by using electrical energy to reverse the chemical reaction • “rechargables” Ex. Car batteries, cell phones, Ni-Cd batteries - will wear out over time

  33. II. Parts of an electrochemical cell • 1 or 2 Electrolytes – a solution or paste that conducts electrolytes (ions) • 2 Electrodes – metals/ solids conductors (allow movement of e-) • Made of different metals • Cathode is positive (receives electrons) • Anode is negative (gives away “Source” of electrons)

  34. III. How A Cell Works 1. Electrons are transferred from the negative electrode through a wire – head to the load (+) (-)

  35. III. How A Cell Works 2. Ions (Ex. Cu2+(aq)) from the electrode are transferred through the solution (electrolyte) to the positive electrode. 3. The anode eventually is “eaten away” or used up (+) (-)

  36. Draw a Cell in Action!Draw a cell with the following parts: -copper electrode, copper solution -nickel electrode, nickel solution -wire -bulb -2 beakers

  37. Cell Lab: Evaluating Cell Design • Summarize the following: • What affect does decreasing the concentration of an electrolyte have on the voltage of a cell? • What affect does using the same electrodes have on the voltage of a cell? • What affect does using different combinations of electrolytes have on the voltage of a cell?

  38. IV. Applications of Cells and Batteries • We can apply batteries in useful ways: Electrochemistry – the study of chemical reactions to produce electricity • Electrolysis – using a battery (electricity) to split a compound into its elements Ex. H20 -->

  39. IV. Applications of Cells and Batteries 2) Electroplating – coating a metal with a thin layer of a wanted metal • The object to be plated is connected to the (-) negative electrode of the battery Ex. Plating inexpensive jewelry with gold

  40. IV. Applications of Cells and Batteries 3) Galvanizing–coating parts with a layer of aluminum oxide (is much harder than aluminum) Ex. Jewellery, screen doors, kitchenware

  41. IV. Applications of Cells and Batteries 4) Electrorefining–removing impurities from metals -impure metals are placed at (+) electrode and a pure metal is placed at (-) terminal.

  42. Connect a circuit so that two light bulbs can be switched on and off together.

More Related