Physics : Spring Semester 2023
~8 weeks
for next year:
bow shocks in plasma, and how the magnetosphere protects Earth from the solar wind:
(click here to return to previous unit) Week 12: March 27 Current, extended projects: New assignments this week.
Additional resources
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Introduction to electricity: Demo's Van DeGraff generator and "lightning ball". Electrons getting knocked loose. Molecules being torn apart. Electric fields are force fields. There are many force fields, each acting on a different aspect of matter. Electric fields are vector fields with conventions for drawing. When discussing electricity, voltage, current and resistance are key components of the discussion. Materials can be insulators or conductors, both of which can carry electricity. Discussion: Electric fields due to storm clouds and charging by induction (demo included use of electroscope which gains charge by simply being near Van de Graff generator) http://www.nytimes.com/2016/08/31/science/lightning-strike-dead-reindeer.html Discussion: Electric field strength is defined as newtons per coulomb. Comparision to gravitional field strength. Charge on an electron, number of electrons required to create one coulomb of charge This week introduces the fudamental concept of electric charge, how charge transfers from one material to another, the forces that develop between charges and how we the concept of the electric field as a vector field and how that field can vary between insulators and conductors. Review/discussion of electric fields and introduction to voltage. Voltage refers to how much energy a charge will gain as it falls "down" an electric field. Much like a rock dropping from a given height (picking up kinetic energy and losing potential energy) a charge will fall through a field and pick up energy (the opposite of the work required to "lift it up" the field. Voltage then is a measure of the "work per charge" which is gained or lost as a charge moves from one place to another within an electric field. |
Awesome footage of lightning strikes Just for fun |
Week 13: April 03 Test after break! (click here for review guide!)
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| STOP! The items listed in the weeks below are from Last years syllabus. In some instances, dates may be changed and assigments/activities may be repositioned on the calendar as time progresses. | ||
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New assignments this week.
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Discussion: What is a complete circuit? When does electricity flow? Any system in which a) there is a potential difference and b) a conducting path for a current to flow through. (note: in most human designed systems, e.g., cars, computers, machines, etc. We usually build circuits that begin and end with a battery, such as the battery in your car or computer. In natural systems (clouds or high voltage power lines).. the complete circuit might be between the clouds and the ground, or between the power lines and a near-by tree branch. Of importance, electricity only flows when there is a difference in electric potential. (an analogy is made of holding a trough of water over my head.. the water will only flow to one side or the other, if the trough is held with one side higher than the other, not if they are at the same height!) In the video clip of the High voltage linemen , the worker doesn't get roasted because he is at the same voltage (500,000 volts!).. as the lines themselves. Guitar building time in the engineering lab! Note to student: These are the text book sections we have 'covered so far' in class discussions.
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| Week 14: April 4: Spring Break | ||
Week 15 April 11 New assignments this week.
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Clark was out on Monday. Tuesday/Wed was CASEE testing.. Thursday including discussion on fhe following topics. The Equivelent Series Resistance of a chemical (eg lead/acid) battery. (described in section 19.1 in the text book, EMF and terminal voltage). Time in Engineering shop (45 minutes) |
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Week 16: April 25
For extra credit only
Associated Text book sections students should review: Additional resources: |
Discussion: Elelctric fields in conductors. Discussion: Simple circuit problems involving resistors in series and in parallel. (section 19.2 in text book). Discussion: Capacitors.. A slow walk through a circuit with capacitors showing how voltage changes as capacitors are charged and discharged.. Having fun with Ultra-capacitors. This video compares capacitors to batteries and illustrates concepts such as equivelent series resistance in batters (ESR), energy stored in capacitors, the definition of capacitance (the ratio of charge to voltage).. the units of capacitance (the Farad).. etc. Note: Some off-color humor in this one, but lots of good physics. |
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Week 17. May 02. Clark is out this week, Mon-Wednesday. (COVID!) New assignments this week.
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Video: Tesla, Master of Lightning. Students are to watch (over Monday and Tuesday) this documentary, taking notes along the way. In class reading assignment: Chapter/section 20.1-20.5. Magnetic fields. Summerize these sections. (pictures and words!) |
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Week 18. May 09. This week was AP testing. Problem set, solving problems using Kirchoff's rules (and your programable calculator). |
Thursday: Mini-lab: Capacitors in a circuit.. Students built four different circuits containing capacitors.. they calculated the capacitance for each circuit and then described the behaviour. Circuit labs: Project 296 +252 (using capacitors to quite a motor and to store energy). For each of these, students should summarize 'the effect' on the circuit of having the capacitor in place. For circuit 2296, the student should determine the charge (Q) stored on the capacitor when fully charged. For circuit 252, the circuit should draw two circuit diagrams (for each of the possible states) illustrating the direction of current flow in the two cases. Introduction to Kirchoff's rules for determining current in complex circuits. This discussion sets up a framework for understanding complex circuit problems. The basic idea, is that a 'walk around branches of a ciruit' must include a summation of voltage changes which add to zero. From this, we can set up simultaneous equations which can be solved using matrix operations (including rref, the reduced, row eschelon function on our programable calculators). (See textbook section 19.3: Kirchoff's rules). |
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Week 19. May 16.
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Discussion: Diodes, Light emitting diodes and transistors. Review guide for test next week. Sections: |
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Week 5: April 29 New assignments this week.
Associated Text book sections students should review: |
Introduction to electric circuit kits: Students should note that all kits come with designated spots for every component. Students should note the location of parts and put them back in the correct locations. Discussion: Series and Parallel circuits, and how to determine the equivelent resistance in circuits so that current and voltage can be determined around a circuit. Lecture/discussion: Voltage walk around a circuit. What does a battery do? What is a complete circuit? Symbols for resistors, switches and batteries. Electro-motive-sources. History of Voltaic piles and the term battery. Continuous current vs. rapid discharge. Doing work to lift charges "up hill, energy wise". Voltage across battery should equal voltages around the circuit. Discussion: Resistors in parallel. In this situation, adding resistors actually reduces the overall resistance. (see section 19.2, p. 522 in text). Discussion included determining the "equivalent resistance" and the "inside out" strategy for determining net, system resistance. Activity/discussion: Building circuit and measuring voltage around the circuit.. using multi-meters to measure voltage. For each of the two circuits below, students were to measure voltage (noting milivolts when multimeter "autoscaled") around each branch of the circuit.
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Week 6: May 06 SBAC Testing this week: Consumed the entire block period of Thurs/Friday classtime. New assignments this week.
Associated Text book sections students should review: |
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Week 7: May 13 Current, extended projects: New assignments this week.
Associated Text book sections students should review:
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Lab: Capacitors in series and parallel. (Snap Circuit projects 164 and 165, respectively) Students were to:
Introduction to capacitance. Capacitors store charge and are used to modulate current flow in circuits (buffer delicate electronics from unexpected surges, for instance) or to store energy and maintain applied voltage when power is shut off (this is how logic circuits such as the memory in your car retain the mileage value even when the car battery is removed). (See textbook section 17.7: Capacitance). Discussion/review: Voltage is only dangerous when there is a 'potential DIFFERENCE' between points.
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High amperage current wants to keep flowing (kind of like inertia), even when the circuit is 'broken', in an effort to shut if off. Associated text book sections on semiconductors, diodes and transistors:
for next year_____________________ Sample capacitor problem: Chapter 17, problem 37. Determine the charge on a capacitor required to achieve an Electric Field of given strength. |
Week 8: May 20 New assignments this week.
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Magnetic and electric interactions. Basic ideas discussed include:
Introduction to Light and geometric optics. (text 23.1: The ray model of light and 23.2: reflection, images formed by a plane mirror). Minilab: images produced by flat (plane) mirrors. Students placed a nail (the object) in front of a flat mirror. Then, using rulers, identified the 'lines of sight' to the 'image' of the nail in the mirror. By connecting these 'rays' students were able to locate where 'the image' was located in space, and to measure the angles of incidence and reflection (and image and object distances as well). Due end of week. |
Additional Text book sections students should review:
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Week 9: May 27 Monday was a holidy: Memorial Day Weekend! |
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Week 2: May 01 Current, extended projects: New assignments this week___________ Video: Tesla, master of lightning! Cornell notes due end of period.
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Discussion: Inductance. Amazingly, electricity can act as if it has momentum/inertia.. (this has to do with the interaction of electric currents and magnetic fields, more on that later
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Week 3: May 08 New assignments this week___________
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Introduction to capacitance. (see chapter 17-7 in text). Capacitors store charge and are used to modulate current flow in circuits (buffer delicate electronics from unexpected surges, for instance) or to store energy and maintain applied voltage when power is shut off (this is how logic circuits such as the memory in your car retain the mileage value even when the car battery is removed). Sample capacitor problem: Chapter 17, problem 37. Determine the charge on a capacitor required to achieve an Electric Field of given strength. Lab: Capacitors in series and parallel. (Snap Circuit projects 164 and 165, respectively) Students were to:
Capacitors video clip: Capacitor fun See what happens when a large capacitor is fully charged! How does a capacitor discharging differ from a battery discharging? |
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Week 4: May 15 New assignments this week___________
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Monday: Intro to optics: The ray model of light, the flat mirror lab. Flat mirror lab: Students viewed a nail set a distance in front of a flat mirror. By drawing "lines of sight" towards the "image", students traced out the true path of light rays, confirming the "law of reflection" and projecting back to where the "image" location would be located. Tuesday: One last electrical system discussion: Kirchoff's rules/matrix operations. Thursday: Concave mirrors/convex mirrors |
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Week 5: May 22 New assignments this week___________
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Monday: Refraction as a wave phenomina (discussion). Wave speed changes waves move from one material into another. This change of speed results in a change of direction as the wave is "dragged down" or "speeds up".. Tuesday: mini-Lab: Snells law lab/bending light at the boundary. Students used semicirular dishes of water to draw "lines of sight" between nails placed on each side of the dish. Using these lines of sight adn by measuring the resulting angles of incidence and refraction on either side of the boundry, students were able to determine the index of refraction and therfor, the speed of light in water. Thursday: Field trip to exploratorium (click here for assignment sheet). |
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Week 6: May 29 Final Review Guide passed out on Tuesday. New assignments this week___________ Final Review guide was passed out on Tuesday. |
Monday: No School, Memorial day holiday Tuesday: Optics Bench mini-lab and discussion. Two kinds of lenses, converging and diverging (with positive and negative focal lengths, respectively) Drawing ray diagrams for lenses follows the same principals as with mirrors, only the rays pass through the lense instead of bouncing off as with mirrors. Thursday: Free time to review for Final, finish up any late work, etc. |
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| Week 7: June 5th Finals week. | ||
The items listed in the weeks below are from Last years syllabus. In some instances, dates may be changed and assigments/activities may be repositioned on the calander as time progresses. |
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What you could be working on to strengthen your skills
Related Text book sections to this week's discussions.
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Week 3: May 16th. Current, extended projects: New assignments this week.
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Addition to previous measurments of voltage activity: : Show that voltages around circuit add up to applied battery voltage. Discussion: Determing the net resistance of a series of resitors. Sample problem: Given a ten volt battery and three resistors in series (1, 2, 3 ohms), what current would flow and what would the voltage drop be across each resistor?. Video (first 15 minutes): |
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Week 4: May 23 Current, extended projects: New assignments this week.
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Introduction to Kirchoff's rules (section 19.3 in text). Clark walked through problem 29 (chpt 19) in text book showing how taking a "voltage walk" around a circuit leads to a summation of voltages which must add to zero. When there are mutilple unknowns, we must have an equal multiple of independant equations to solve. By using Kirchhoff's strategies, we can construct a series of equations, and then by putting them into standard "matrix form", we can use the "reduce row eschelon" feature of our programmable calcutlators to solve them simultatneously. (practice worksheet). Discussion: Internal voltage of a battery
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Week 5: May 31 New assignments this week.
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Discussion: Magnetic fields and effects on compasses.. magnetite.. 3rd experiements.. what the field lines show us.. the Earth's magenetic field.. (sections 20.1 and 20.2).
Current measurement techniques are compared to voltage measurement techniques. Current measurements are always made with the ammeter in series with the circuit branch of interest. Voltage measurements are made in parallel ot the circuit element of interest. Measuring voltage is always safe and won't affect the circuit (assuming your multimeter is in the correct mode) whereas measuring current can lead to circuit overloads and blown ammeters if one is not careful. Review of resistors in parallel and in series and how current and voltage are affected. (practice worksheet) Introduction to Lenz's law (Farday's law of induction).. basic sequence:
Demo: Neodymium magnets dropped down into a copper pipe (copper is non-magnetic) producign eddy currents which create magnetic fields which oppose the "changing magnetic field". (section 21.5 in text). After Quiz on Thursday: Article: Sound Bytes. This article describes how the human auditory system is more senstitive than our visual system and the concept of mapping data int sound files can lead to more precise recognition of patterns which otherwise would go unnoticed. Students read article and responded to these quided questions.
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Week 6 FINALS WEEK! Clark is at Water World on Monday! |
Please see finals schedule for test times. |
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Introduction to electromagnetism. (chpt 20 in text).
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Week 5: June 1st
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Build a speaker: Clark provides the parts, students construct in teams of three. Design and place inside a box with a place to mount amplifier circuit. Due Next week (must work for 20 pts). |
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for next year:
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Discussion: electrical basics: how to read resistors. Introduction to power in circuits (prereq for understanding value of transformers, next week) and amplifiers. Add an amplifier: NPN General purpose amplifier 2N3392 (data sheet) and wiring diagram College peek: build an amplifier circuit with integrated circuits |
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