Unit: Charge Differentiated Task Light it Up!

Transcription

1 The following instructional plan is part of a GaDOE collection of Unit Frameworks, Performance Tasks, examples of Student Work, and Teacher Commentary. Many more GaDOE approved instructional plans are available by using the Search Standards feature located on GeorgiaStandards.Org. Georgia Performance Standards Framework for Physical Science High School Subject Area: Physical Science Grade: High School Standards (Content and Characteristics): Unit: Charge Differentiated Task Light it Up! SPS10. Students will investigate the properties of electricity and magnetism. a. Explain the flow of electrons in terms of Alternating and directing current. The relationship among voltage, resistance and current. Simple series and parallel circuits. SPS8 Students will determine relationships among force, mass, and motion. a. Apply Newton s three laws to everyday situations by explaining the following: Inertia Relationship between force, mass, and acceleration Equal and opposite forces SCSh1. Students will evaluate the importance of curiosity, honesty, openness, and skepticism in science. a. Exhibit the above traits in their own scientific activities. b. Recognize that different explanations often can be given for the same evidence. c. Explain that further understanding of scientific problems relies on the design and execution of new experiments which may reinforce or weaken opposing explanations. SCSh2. Students will use standard safety practices for all classroom laboratory and field investigations. a. Follow correct procedures for use of scientific apparatus. b. Demonstrate appropriate techniques in all laboratory situations. c. Follow correct protocol for identifying and reporting safety problems and violations. PHYSICAL SCIENCE HIGH SCHOOL CHARGE! Page 1 of 7

2 SCSh3. Students will identify and investigate problems scientifically. a. Suggest reasonable hypotheses for identified problems. b. Develop procedures for solving scientific problems. c. Collect, organize and record appropriate data. d. Graphically compare and analyze data points and/or summary statistics. e. Develop reasonable conclusions based on data collected. f. Evaluate whether conclusions are reasonable by reviewing the process and checking against other available information. SCSh4. Students will use tools and instruments for observing, measuring, and manipulating scientific equipment and materials. a. Develop and use systematic procedures for recording and organizing information. SCSh5. Students will demonstrate the computation and estimation skills necessary for analyzing data and developing reasonable scientific explanations. a. Trace the source on any large disparity between estimated and calculated answers to problems. b. Consider possible effects of measurement errors on calculations. c. Recognize the relationship between accuracy and precision. d. Express appropriate numbers of significant figures for calculated data, using scientific notation where appropriate. e. Solve scientific problems by substituting quantitative values, using dimensional analysis, and/or simple algebraic formulas as appropriate. SCSh6. Students will communicate scientific investigations and information clearly. a. Write clear, coherent laboratory reports related to scientific investigations. c. Use data as evidence to support scientific arguments and claims in written or oral presentations. d. Participate in group discussions of scientific investigation and current scientific issues. SCSh9. Students will enhance reading in all curriculum areas by: c. Building vocabulary knowledge Demonstrate an understanding of contextual vocabulary in various subjects. Use content vocabulary in writing and speaking. Explore understanding of new words found in subject area texts. d. Establishing context Explore life experiences related to subject area content. Discuss in both writing and speaking how certain words are subject area related. Determine strategies for finding content and contextual meaning for unknown words Page 2 of 7

3 Enduring Understandings: The student will understand that: Electric current is the result of the motion of charged particles across a conductor. Friction forces can cause the accumulation of an unbalanced amount of charged particles on the surface of an object. The voltage created between two objects due to the presence of an unbalanced charge may create an electric spark or shock. Electrons can be transferred from one charged conductor to another by physical contact. An electric current requires a complete circuit and a voltage source. The amount of current that flows in a circuit depends on both the resistance and the voltage of the source. In a series circuit the same amount of current flows through all the components. In a parallel circuit the voltage drop across each component is equal and equal to the voltage of the power source. In a direct current circuit the electrons flow in only one direction. In an alternating current circuit the motion of the electrons alternates back and forth due to the changing polarity of the voltage source. Essential Question(s): What does it mean when something is electrically charged? How can an object become electrically charged? Why can small birds sit on high-voltage power lines? Why is an alternating current necessary for a motor to work? What characteristics of the material make it a good conductor or insulator? Why are insulators attracted to charged objects? Why is alternating current commonly used in household applications? Pre-Assessment: Give students three-five statements about the standards listed above and a scale that goes from true, false, maybe, and no idea. This can be done as a ticket-out-the-door the day prior to beginning this unit. Evaluate the quiz results and group students based on their current knowledge level. This will allow the teacher to give a brief introduction to this activity and then work with the no idea group for minutes, the maybe group for 5-10 minutes, and the true group for only a few minutes to get everyone started. Then the teacher should be able to navigate the room offering help where needed. Teacher Note: It may be necessary to review the concepts related to Newton s Laws of Motion as they apply to the movement of charges in a circuit prior to this activity Page 3 of 7

4 Outcome/ Performance Level Indicator Performance Task: (Detailed Description) Teacher role? Student role? BASIC INTERMEDIATE ADVANCED Students will Students will design, construct and construct and differentiate between differentiate between series and parallel series and parallel circuits, measure the circuits, measure the voltage and current voltage and current across the circuit, and across the circuit, and calculate the calculate the resistance using resistance using Ohm s Law. Ohm s Law. Students will construct a series and parallel circuit using detailed instructions. Students will differentiate between the two, measure voltage and current across the circuit, and calculate the resistance using Ohm s Law. Using the materials and procedures below, the teacher will explain and demonstrate how to set up a circuit. Following the teacher s demonstration, the students will then construct series and parallel circuits. Students will measure voltage using a voltmeter and current using an ammeter. Using voltage and current measurements, students will calculate resistance in each circuit using Ohm s Law. Students will use two resistors. Using the materials and procedures below, the teacher will allow students to construct their own circuits. Students will measure voltage using a voltmeter and an ammeter to measure current. Using voltage and current measurements, students will calculate resistance of each resistor in each circuit using Ohm s Law. Students will use more than two resistors. Using the materials and some guiding questions (see teacher note below), the teacher will allow students to design and construct their own circuits. Students will construct series and parallel circuits and using the equipment that is provided measure voltage and current across the circuit. Using voltage and current measurements, students will calculate resistance of each resistor in each circuit using Ohm s Law. Students will use more than two resistors of different types. Resources lab and websites attached below lab and websites attached below lab and websites attached below Page 4 of 7

5 Homework/Extension Instructional Tasks Accommodations for ELL Students Instructional Tasks Accommodations for Students with Specific Disabilities Instructional Tasks Accommodations for Gifted Students homework attached homework attached homework attached below below below Procedures could be translated and recorded on audio cassette by language teacher and given to student prior to lab. ELL student could play a major role in building circuits, taking measurements, and discussing observations and outcomes while lab partner (Englishspeaking) records data and writes report. Provide teacher formatted lab sheet. Provide video clips for content. Allow simple schematics to be used. Pair disabled student with regular student. The disabled student could build circuits, take measurements, and discuss observations and outcomes while lab partner records data and writes report. Provide teacher formatted lab sheet. Provide video clips for content. Allow simple schematics to be used. Working in pairs, students should show all resistance calculations. Students must also include a switch and a door bell in the circuit where the doorbell remains on even when the lights go off. Web Resources for interactive circuits and other electronic components: It may be beneficial for students to access these sites prior to the performance task Materials: 2 size-d dry cells (batteries) Various pieces of copper wire flashlight bulbs, sections of holiday lights or various resistors bulb holders if available battery holders if available alligator clips if available 1 voltmeter 1 ammeter 1 switch For demonstration purposes one large scale series circuit one large scale parallel circuit light bulbs, resistors of various wattages Page 5 of 7

6 Safety Hazards: Students should wear goggles and aprons. Avoid batteries coming in contact with water and other liquids. Caution students that battery connections will generate heat. Student lab setups should not exceed more than 2 D batteries. Teacher note: Provide students with a data table to save time. Differentiate the materials and the instructions/diagrams that are available to each group. For example: Group 1: (Basic) Detailed instructions which include a teacher demonstration. Diagram of each circuit. Only provide two resistors Group 2: (Intermediate) Instructions More than two resistors Group 3: (Advanced) Procedure is not provided for this group. This group will write their own procedure using guiding questions. Examples of questions may include: 1. How can your group power the given resistors using the materials that are provided? 2. Design a circuit that will power resistors in the circuit even when one resistor is disabled or removed. Several resistors of varying types (door bell, buzzer, holiday lights, flashlight bulbs etc.) Procedure 1. Using the given materials, construct a series circuit that contains a power source (1 battery), a resistor, wires, and a switch. Diagram your completed circuit showing the flow of energy when the switch is open and when it is closed. Explain what happens when the switch is opened and why. 2. Connect the voltmeter and measure the voltage across the circuit. Remove the voltmeter and replace with the ammeter to measure the current across the circuit. Record your observations in your data table. 3. Repeat steps one and two adding a resistor. Diagram your circuit and record your observations in your data table. 4. Add the second battery and attempt to power all of the resistors that were provided in your lab equipment. Diagram each arrangement, measure the voltage and current and record your observations in your data table. 5. In the circuit with two bulbs, unscrew one of the bulbs. Record your observations. 6. Repeat this procedure for the parallel circuit Page 6 of 7

7 Additional Notes One Stop Shop For Educators Series Circuits Devices in series are dependent upon each other to operate properly. The total resistance in a circuit is equal to the sum of the individual resistances along the current path. R T = R 1 + R 2 + R 3 etc. The potential difference, or voltage, is decreased over each resistance. The voltage drop across each device is directly proportional to its resistance. Parallel Circuits Devices act independently of each other and can operate properly even when one or more resistors become disabled. The total equivalent resistance is less than the value of any individual resistor. Each device connects the same two points of the circuit; therefore, the voltage is the same across each device. The total current is equal to the sum of the currents in each branch. I T = I 1 + I 2 + I 3 etc. Homework Problems Basic and Intermediate 1. You are to draw a series circuit schematic with a battery as the source and three resistors. Then calculate the voltage if the current of the circuit is 1875 amps and the resistors have the following values: R 1 =7.00 Ohms, R 2 =5.00 Ohms, and R 3 =8.00 Ohms. What would the voltage be across each resistor? Advanced 2. You are to draw a parallel circuit schematic with a battery as the source and two resistors. Then calculate the current if the battery is supplying volts across two resistors with R 1 =5.00 Ohms and R 2 =12.00 Ohms. What is the current across each resistor? Draw a series circuit schematic with one battery and two resistors. Applying the same voltage and resistance values to this circuit (as listed at the beginning of this problem), determine the total current and the current across each resistor Page 7 of 7