Electricity & Circuits & for juniors: Electromagnetism

Know basic circuit symbols (notes)

Intro to Circuits activity Do not directly connect the ends of a battery with wire… …without any resistance, too much electricity will flow and destroy battery, or worse.

Intro to Circuits activity Build the following devices. Once functional, draw circuit diagrams for each : Source of electrical voltage (battery) + light + switch Source of voltage + two slightly dimmer lights Source of electrical voltage + two equally bright lights Source of voltage + two switches controlling two separate lights. Source of voltage + one switch, two conditions one bright light or two dim lights

Basic Learning Objectives Correctly interpret & use circuit symbols. Identify & know properties of light bulbs & resistors placed in series vs. parallel circuits. Describe meaning of voltage, potential, voltage drop, current, amperage. Use water analogies. Describe voltage drop across resistors. Describe difference between DC and AC power.

Intermediate Learning Objectives Calculate resistance of multiple resistors in series and in parallel, in correct units. Predict circuit amperage using Ohm’s Law. Describe how to use a voltmeter and ammeter correctly. (We will use combined multi-meters.) Describe the purposes and function of fuses, circuit breakers and GFIs.

Advanced Learning Objectives Describe how capacitors work, such as in parallel to a bulb on a circuit whose voltage can be turned on/off. Draw a series of circuit diagrams using color-coding to show ‘pressure’ and electron ‘flow’ at different moments in time in circuits with capacitors. Wire a house model with a variety of circuit types. Describe the phenomenon of electromagnetism. Describe how to build devices using electromagnetism: generator, motor, speaker, transformer. (Juniors only)

Have you read? Chapter 35 - Basic Learning Objectives Chapter 34 - Intermediate LO’s Chapters 36-37 - Advanced LO’s

Background on Electrical Current & Circuits Go to this site: http://www.physicsclassroom.com/ Open Classroom Tutorial mode Open Current Electricity chapter Read through each lesson: 1) Potential 2) Current 3) Resistance 4) Circuits Complete Q’s at bottom each lesson, check A’s

Points to discuss based on student Q’s Indicated direction of current - Conventional vs. Electron Flow Ben Franklin vs. modern understanding of electrical current Battery polarity, resistor polarity, does current direction matter Purpose of battery in circuit How a battery works and why multiple lines in diagram (2 electrodes/cell) Circuit continuity, open vs. closed Equivalent ways to draw circuits – bends don’t matter, distance (mostly) doesn’t matter. How to show non-connected wires ‘jumping’ each other Bulbs are resistors too Series vs parallel; dealing with both in same circuit How an incandescent screw-in bulb works

Points to discuss based on student Q’s Water reservoir & gravity = analog for pressure or flow How it relates to voltage (= potential), voltage drop, amperage (= current) Electric field = electric potential; drawing arrows for effect on + test charge Calculating resistance of series of resistors Using Ohm’s Law to find current flow Calculating resistance of resistors in parallel Circuit w both?

QUIZ See if you can answer questions on the following slides using prose & pictures. Each slide matches an Electricity & Circuits learning objective .

Basic Learning Objectives Correctly interpret & use circuit symbols. Q: What are these circuit components?

Basic Learning Objectives Identify & know properties of light bulbs & resistors placed in series vs. parallel circuits. Q: Label these circuits as series or parallel.

Basic Learning Objectives Describe meaning of voltage, potential, voltage drop, current, amperage. Use water analogies. Q: Match the correct water analogy to concepts above.

Basic Learning Objectives Describe voltage drop across resistors. Q: Draw a circuit diagram to represent this water analogy.

Basic Learning Objectives Describe difference between DC and AC power. Q: Draw the corresponding voltage-over-time graph and for AC and the cartoon for DC.

Intermediate Learning Objectives Calculate resistance of multiple resistors in series and in parallel, in correct units. Q: Calculate the total resistance of each circuit:

Intermediate Learning Objectives Predict circuit amperage using Ohm’s Law. Q: Write Ohm’s Law in symbols and words.

Intermediate Learning Objectives Predict circuit amperage using Ohm’s Law. Q: Calculate the current in each circuit with correct units.

Intermediate Learning Objectives Describe how to use a voltmeter and ammeter correctly. (We will use combined multi-meters.) Q: In what mode is the multi-meter being used in each picture? What are the critical differences?

Intermediate Learning Objectives Describe the purposes and mechanism of fuses, circuit breakers and GFIs.

Intermediate Learning Objectives Describe purpose and mechanism of fuses, circuit breakers and GFIs.

Advanced Learning Objectives Describe how capacitors work. http://www.physbot.co.uk/capacitance.html http://s.hswstatic.com/gif/capacitor-5.gif http://i1-news.softpedia-static.com/images/news2/How-Capacitors-Work-4.jpg

Advanced Learning Objectives Explain the function of a capacitor placed in series or parallel with a lightbulb circuit that can be turned on/off. http://www.grumpyoldgeek.net/images/fullcircuits_clip_image055.jpg http://media.tumblr.com/tumblr_lg7ajm2J0a1qf00w4.png

Advanced Learning Objectives Wire a house model with a variety of circuit types.

Advanced Learning Objectives Describe the phenomenon of electromagnetism. Right-Hand Rule http://www.school-for-champions.com/science/images/electromagnetism__coiled_wire.gif http://upload.wikimedia.org/wikipedia/commons/thumb/3/3e/Manoderecha.svg/2000px-Manoderecha.svg.png https://d2gne97vdumgn3.cloudfront.net/api/file/jykOLZyTcOjR9MBPCwVA

Advanced Learning Objectives Describe how to build devices using electromagnetism: generator, motor, speaker, transformer. Describe how they operate. http://cse.ssl.berkeley.edu/img/cupspker.gif http://www.creative-science.org.uk/projects/cangen/canweb3.jpg http://www.sfu.ca/phys/demos/demoindex/eandm/em5k/simple_motor.jpg http://www.instructables.com/files/deriv/FCA/I8LY/GRTHT6BX/FCAI8LYGRTHT6BX.SMALL.jpg http://o.aolcdn.com/hss/storage/midas/1c98cbe0c638ecb7f08751689b2a828e/200355500/diy-iphone-speaker.jpeg http://www3.sciencedump.com/sites/www.sciencedump.com/files/imagecache/flabv2/cus_thumbs/emvideo-youtube-wT4vdQJ6984.jpg http://www.talkingelectronics.com/projects/200TrCcts/images/SpkrTransf.gif http://img.wonderhowto.com/img/17/64/63494816937690/0/make-paper-plate-speaker-actually-works-for-under-1.w654.jpg

House Wiring Project Must include these functioning elements: Doorbell switch outside & doorbell inside door Single hall light controllable from two switches: inside front door & by bedroom Bathroom venting fan for mildew & odor control Dining room light controlled by one switch with three settings: off, low light, bright light Living room ‘live’ outlet for plugging in entertainment system Bedroom light that turns on gradually, off>dim>bright so as not to blind dilated night eyes Power distribution panel in the utility room, with connections to street lines, sending electricity to each room circuit Functioning fuse for each room circuit on utility room distribution panel, with fuse adjusted for load in each (A+)

House Wiring Project House floorplan on large board with rooms labeled: entrance hall, bathroom, kitchen/dining room, bedroom, living room, utility room Wiring schematic or diagram on floorplan All components installed through board, operable from front, wired in back

Electromagnetic Devices Project Juniors only Successfully build: World’s simplest electromagnetic generator World’s simplest electrical motor World’s simplest speaker that makes recognizable music World’s simplest voltage step-up/step-down transformer World’s simplest microphone

Electromagnetic Devices Project Juniors only Evaluation criteria: Successful, working device? 8 x 11 illustrated poster explaining clearly how it works? Accurately explain it to group verbally? Due by Th 6/18 at latest. Can present whenever done: Th 6/11 (55 min), M 6/15 (55 min), Tu 6/16 (30 min), W 6/17 (2 hrs), Th 6/18 (30 min) = 4 hrs 50 min total