Subject: - Currituck County Schools



|Subject: Physics |Timeframe Needed for Completion: 14 days |

|Grade Level: 11,12 | |

|Unit Title: Unit 8: Electricity |Grading Period: 2nd 9wks |

|New 2009 goals are in red | |

|Big Idea/Theme: Static and Current Electricity |

|Understandings: Students will understand how static electricity if produced. |

|Students will understand how the electroscope works. |

|Students will understand how series and parallel circuits conduct electricity. |

|Students will understand voltage, amperes and electrical resistance in combination circuits. |

|Essential Questions: |Curriculum Goals/Objectives (to be assessed at the end of the unit/quarter) |

|Why do we get shocked in the winter when touching metal objects? |3.1.1 |

|How is electricity produced? |Explain qualitatively the fundamental properties of the interactions of charged objects. |

|What is an electrical circuit? |• Identify basic principles related to the nature of electrical charge – like charges repel and opposite charges attract; there are two |

|What is lightning? |types of electric charge (positive and negative); positively charged objects have an electron deficiency while negatively charged objects |

| |have an excess of electrons. |

| |• Conclude that charge is conserved in a closed system – since charge is a result of fundamental properties of particles, charge (like |

| |atoms) cannot be created nor destroyed. |

| | |

| | |

| |3.1.2 Explain the geometries and magnitudes of electric fields. |

| |• Construct diagrams to illustrate electric fields and explain its vector nature: |

| |♣ around single positive and negative charges, |

| |♣ between a pair of like charges, |

| |♣ between a pair of unlike charges, |

| |♣ two oppositely charged parallel plates, |

| |♣ a hollow sphere, |

| |♣ an irregular shaped metal object. |

| |• Compare the strength of various points in an electric field where |

| |♣ and for a point charge |

| |♣ for the uniform electric field between parallel plates. VEd= |

| |• Distinguish between charge distribution on plates and a hollow conducting sphere where no electric field exists inside. |

| | |

| |3.1.3 Explain how Coulomb’s law relates to the electrostatic interactions among charged objects. |

| | |

| |• Conceptually and mathematically explain electrical attraction and repulsion using Coulomb’s law - the electrical force is directly |

| |proportional to the product of two charges and inversely proportional to the square of the distance between them, . 122ekqqFd= |

| |• Determine the magnitude and direction of an electric force between two charges. |

| | |

| |3.1.4 Explain the mechanisms for producing electrostatic charges including charging by friction, conduction, and induction. |

| |Explain situations where objects become charged (by friction, conduction or induction) in terms of the transfer or rearrangement of |

| |electrons: |

| |• two neutral objects charged by friction, |

| |• a neutral object becoming positively charged by induction and conduction, |

| |• a neutral object becoming negatively charged by induction and conduction. |

| | |

| |3.1.5 Explain how differences in electrostatic potentials relate to the potential energy of charged objects. |

| |• Compare work done on an object by lifting (changes in location in a gravitational field) to work done on a charged particle by pushing |

| |it |

| |against the electric field of a charged object – both positive and negative. |

| |• Define electric potential energy as the energy of a charge based on its location and distinguish electric potential (voltage) as being |

| |the |

| |same for all charges. |

| |• Conclude that a gravitational field is always in one direction while electric fields have two possible directions; by convention, the |

| |direction is determined by the direction of force on a positive test charge – away from (out of) a positive charge and toward (into) a |

| |negative charge. |

| | |

| |2.3.1 Explain Ohm’s law in relation to electric circuits. |

| | |

| |• Recognize that a difference in potential (voltage) creates current within a conductor; the amount of current also depends on the |

| |resistance of the conductor. |

| |• Develop a cause-and-effect model for current in a circuit - current is directly proportional to the voltage and inversely proportional |

| |to |

| |the resistance (Ohm’s law), |

| |• Given a schematic circuit diagram, determine current, voltage, or resistance from two known quantities. |

| | |

| |2.3.2 Differentiate the behavior of moving charges in conductors and insulators. |

| |• Identify conductors as materials that have electrons that are free to move throughout the sample; Metals are good conductors of |

| |electrical charge. |

| |• Identify insulators as materials where electrons are held tightly to individual nuclei; Rubber and glass are examples of insulators that|

| | |

| |because of their properties develop static charge readily through friction with other materials. |

| |• Explain classification as a conductor or insulator based on the ability of electric charge to move through the material. |

| | |

| |2.3.3 Compare the general characteristics of AC and DC systems without calculations. |

| |Compare alternating and direct current systems based on the source of electrical energy, transmission over distances, ease of use in |

| |varied |

| |electrical devices, etc. |

| | |

| |2.3.4 Analyze electric systems in terms of their energy and power. |

| |• Develop the concept of power using dimensional analysis (unit cancellation) where electrical power can be calculated from current, |

| |voltage and/or resistance measurements, |

| |• Since power is defined as the rate of work done or energy transferred, energy used by a device can be calculated by multiplying power |

| |and time, |

| | |

| |2.3.5 Analyze systems with multiple potential differences and resistors connected in series and parallel circuits, both conceptually |

| |and mathematically, in terms of voltage, current and resistance. |

| |• Analyze series circuits to distinguish the following patterns for current, voltage, and equivalent resistance: |

| |♣ Current is the same throughout the circuit |

| |♣ Voltage drop across each resistor is proportional to the resistance and additive for the circuit, |

| |♣ Equivalent resistance for the circuit is the sum of resistances, |

| |• Analyze parallel circuits to distinguish the following patterns for current, voltage, and equivalent resistance: |

| |♣ Current in parallel branches divides in an inverse proportion to the resistance; the sum of the current through each device equals |

| |the current supplied |

| |♣ Voltage drop across each branch is the same |

| |♣ Equivalent resistance for the parallel branch is the inverse of the sum of the resistance reciprocals, |

| |(Equivalent resistance in a parallel arrangement is lower than any one resistance in the arrangement.) |

| |• Conclude that multiple potential difference (voltage) sources are additive when arranged in series; current moving from positive to |

| |negative constitutes a negative potential difference. (e.g. - Two six volt batteries in series connecting positive to negative terminals |

| |have a combined potential difference of twelve volts; a six volt battery in series connecting positive to positive terminals with a three |

| |volt battery would establish a combined potential difference of three volts.) Network circuits where a second emf is located in a |

| |branch should not be included in the standard level course. |

| |• Analyze series-parallel combination circuits by determining equivalent resistance of portions of the circuit until it can be reduced to |

| |a |

| |simple series or parallel circuit. |

| | |

| | |

| | |

|Essential Skills/Vocabulary: |Assessment Tasks: |

|Conduct investigations involving static electricity. |Major test, quizzes, homework |

|Analyze the nature of electrical charge. |Lab on Series Circuits |

|The two different kinds of electric charge are defined as positive and negative. |Lab on Parallel Circuits |

|Like charges repel and unlike charges attract. |Lab on Combination Circuits |

|Understand that matter is neutral when charges are balanced and becomes charged |Website on Electricity and Building Circuits |

|when there is a transfer of electrons. |Rotational Lab |

|Recognize the three methods of charge transfer are friction, conduction, and |(Students rotate around 6 lab tables and observe electrical phenomena) |

|induction. | ( FOR SUPPLIES NEEDED TO ACCOMPANY THE BELOW “INQUIRY SUPPORT LABS”)|

|Understand that electric charge is conserved (neither created nor destroyed and | |

|may be transferred from one object to another). |Electrostatic lab-investigating electrostatics using common household items such as making an electroscope from cellophane tape, balloons |

|Calculate the electrostatic force between any two point charges using the |or pie pans |

|equation: [pic] |Inquiry Support Lab: Sticky Tape Lab |

|Apply the inverse square relationship between the force and the distance between |Current and resistance lab |

|the charges. |Inquiry Support Lab: Circuit Activity |

|Apply the proportional relationship between the force and the product of the |Inquiry Support Lab: Verifying Ohm’s Law |

|charges. |Inquiry Support Lab: Ohm’s Law Activity |

|Cite evidence from experiments to support the existence of two kinds of charge, |Inquiry Support Lab: Current and Voltage for Resistors in Series, Parallel, and Mixed Circuits |

|the neutrality of most matter, and explain charging by friction, conduction and | |

|induction. |Inquiry Support Lab: Voltage Activity |

|Apply Ohm’s Law: [pic] | |

|Solve simple circuit problems. | |

|Graph results from investigations. | |

|Observe how potential difference, current and resistance affect the brightness of | |

|light bulbs in circuits with batteries. | |

|Design and conduct investigations to measure potential difference and current in | |

|direct current circuits with resistors and batteries. | |

|Series circuits | |

|Recognize that current is the same throughout the circuit: [pic] | |

|Recognize that voltage divides proportionally to the resistance. The sum of the | |

|voltage drops across the circuit equals the potential difference supplied to the | |

|circuit: [pic] | |

|Calculate equivalent resistance: [pic] | |

|Apply Ohm’s law to series circuits. | |

|Parallel circuits | |

|Recognize that current divides in inverse proportion to the resistance. The sum | |

|of the current through each device equals the current supplied to the circuit: | |

|[pic] | |

|Recognize that the voltage drop across each branch is the same: [pic] | |

|Calculate equivalent resistance: [pic] | |

|Apply Ohm’s law to parallel circuits. | |

|Combination circuits | |

|Calculate equivalent resistance. | |

|Develop a conceptual understanding of voltage and current in a combination | |

|circuit. | |

| | |

|AC/DC Systems | |

|Calculate and compare alternating and direct current systems based on the source | |

|of electrical energy. | |

| | |

|Materials Suggestions: |

| ( FOR SUPPLIES NEEDED TO ACCOMPANY THE BELOW “INQUIRY SUPPORT LABS”) |

| |

|Transparent tape |

|Soda can |

|Styrofoam cup. |

|Dry cell |

|Wire flashlight bulb |

|10 watt power resistors |

|6- 1.5 V dry cells |

|Ammeter |

|Voltmeter |

|One variable voltage DC power supply, one ammeter and one voltmeter (or two multimeters) per group of 2 – 4 students. |

|Various resistors. |

|Various connecting wires. |

|Graphing software. |

|21st Century Skills |Activity |

|Communication Skills | |

|Conveying thought or opinions |Analysis questions in all labs |

|effectively | |

|When presenting information, |Data collection in all Lab Activities |

|distinguishing between relevant and | |

|irrelevant information | |

|Explaining a concept to others |Sign Off—Sticky Tape lab |

| |Circuit Activity |

| |Ohm’s Law activity |

|Interviewing others or being |Sign Off—Sticky Tape lab |

|interviewed |Circuit Activity |

|Computer Knowledge | |

|Using word-processing and database |Making graphs in labs |

|programs | |

|Developing visual aides for |Sticky Tape Lab |

|presentations | |

|Using a computer for communication |Sticky Tape |

| |Ohm’s Law Activity |

|Learning new software programs |Circuit Web link |

|Employability Skills | |

|Assuming responsibility for own |Sticky Tape |

|learning |Activities |

| |Sign Off –Circuit & Ohm’s law Activity |

|Persisting until job is completed | |

|Working independently |Sticky Tape |

|Developing career interest/goals | |

|Responding to criticism or questions |Sign Off –Sticky Tape |

| |Ohm’s Law |

|Information-retrieval Skills | |

|Searching for information via the |Voltage Activity |

|computer | |

|Searching for print information |Current and Voltage for Resistors in Series & Parallel |

|Searching for information using |Current and Voltage for Resistors in Series & Parallel |

|community members | |

|Language Skills - Reading | |

|Following written directions |Most of the activities can be presented as opportunities for students to follow written |

| |directions. The teacher will have to work with most students to develop this skill over |

| |time. |

|Identifying cause and effect |Sticky Tape |

|relationships |Ohm’s Law |

|Summarizing main points after reading | |

|Locating and choosing appropriate |All lab activities |

|reference materials | |

|Reading for personal learning | |

|Language Skill - Writing | |

|Using language accurately | |

|Organizing and relating ideas when |“Explain” and “Evaluate” sections in all lab activities |

|writing | |

|Proofing and Editing | |

|Synthesizing information from several |Current and Voltage for Resistors in Series & Parallel |

|sources |Sign Off Activity |

|Documenting sources | |

|Developing an outline | |

|Writing to persuade or justify a |Sign Off Activity |

|position | |

|Creating memos, letters, other forms of| |

|correspondence | |

|Teamwork | |

|Taking initiative |All lab activities |

| |Sign Off Activity |

|Working on a team |All lab activities |

| |Sign Off Activity |

|Thinking/Problem-Solving Skills | |

|Identifying key problems or questions |All lab activities |

| |Sign Off Activity |

|Evaluating results |All lab activities |

| |Sign Off Activity |

|Developing strategies to address | |

|problems | |

|Developing an action plan or timeline | |

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