Teacher Notes for Static Electricity

 

Lesson Plans || Learning Outcomes and Activities || Teacher Notes || Labs

 

Unit Overview

We estimate this to be a 15-day unit. An additional day should be added for an exam. There is one primary goal for this time:
 

1. To understand how objects become charged and the effect of that charge on other objects in the surroundings.

All the labs and activities can be tied to this over-arching goal. The unit begins with a review of the structure of the atom and what it means to say an object is charged. Students then learn about the three types of charge interactions (charged objects attracting neutral objects being included as the third) and learn how the third type is explained by the phenomenon of polarization. Three charging methods are introduced and explained in terms of subatomic particles. Coulomb's law is introduced but only used as a guide to thinking about how a change in a variable affects the electrostatic force is discussed. Finally, the concept of an electric field is used to explain the action at a distance. There is never an emphasis upon substitution of values into an equation to solve for an unknown; equations are only used for proportional thinking.

The Lesson Plans include four different hands-on labs. Additional labs can be found in the Laboratory section of the website. 



 

Labs

We have proposed four labs for this unit. Since two of these do not have any Teacher's Guides available, we will supply some notes here. Additional details are on our Lab Page for this unit.

Lab 1: Lab 1 requires the use Scotch tape, a support pole to hang tape strips from, a PVC tube, animal fur or wool, and small paper bits. Tapes can be charged as follows: pull off a 10" piece of tape and fold a small corner on itself. Place adhesive side down on a table. This is the "B-Tape" (B is for on the bottom). Prepare a similar size piece of tape and place it on top of the B-Tape. This top tape is the "T-Tape". Pull the two tapes apart briskly and hang from the support poles on opposite sides. Test each tapes interaction with one another and with paper bits. Rub PVC with fur to charge it negatively and bring it near to each tape and observe its interaction. The conclusion can be formulated from these observations.

Lab 2: Lab 2 is identical to a lab that we have used for our other courses. We have provided a link to the Teachers Guide on our Lab page.

Lab 3: Lab 3 requires the use of an aluminum pie plate (tape a styrofoam cup to its surface as an insulating handle), a PVC tabe, a T-Tape and a B-Tape (suspend from a support), neutral paper bits, a Van de Graaff generator (or highly charged conducting object), and animal fur or wool. The PVC tube is the insulator; the Al pie plate is the conductor. Rub each object with animal fur; observe their interaction with the tapes and neutral paper bits. Touch each object to the charged VDG; observe their interaction with the tapes and neutral paper bits. Charge one side of Al pie plate with the VDG; test the interaction of the opposite side with the tapes and the neutral paper bits. Rub one end of the PVC tube with animal fur; test the interaction of the opposite end with the tapes and the neutral paper bits. Conclusions can be draw from these observations.

Lab 4: Lab 4 is identical to a lab that we have used for our other courses. We have provided a link to the Teachers Guide on our Lab page.

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Our Mathematical Approach to Coulomb's Law

Those familiar with Paul Hewitt's Conceptual Physics textbook will recognize the phrase "Equations are guides to thinking". That is, equations can be more than just recipes for algebraic problem-solving. They can be powerful tools for predicting how a quantity will change if one of the variables it depends upon is changed. Doubling one of the variables will often producing a doubling or halving or a quadrupling or a ... of another variables. Using equations as predictive tools requires an understanding of the proportional relationship between the variables in the equation. 

We have borrowed this approach throughout our Conceptual Physics course. But we have relied on it exclusively in this unit with Coulomb's law equation and the equation for electric field strength. Students will not substitute numerical values into the Coulomb's law equation. They will not not need to use the value of k. They will not need to deal with units like cm and m, C and µC, etc. And they will not need to worry about entering values into their calculator using scientific notation. All that has been removed from this unit of Conceptual Physics. But students are not off the hook entirely; they will need to use the Coulomb's law equation as a guide to thinking.


 

Calculator Pad

We have provided a single CalcPad assignment. The problem set includes five problems in which students use Coulomb's law as a guide to thinking. For teachers who wish to use a more traditional substitute-and-solve approach, you will find plenty of them in the Static ElectricityElectrostatics chapter of our Calculator Pad. With a Task Tracker account, you can easily add problems to the set we have provided for the Conceptual Physics course. You will find directions and video walk-throughs in the Teacher Resources section of your account. With the Task Tracker account, you can even add additional problem sets if you would like. There's no shortage of problems around The Physics Classroom and using the Calculator Pad with Task Tracker gives you control over how you can take advantage of them.


 

"Saving Time"

Those who wish to reduce some time on this topic could easily do so. The following Learning Outcomes and the associated days to address them could be dropped without affecting the other topics in the unit. 
 

• Learning Outcome 7: Coulomb's Law (recover 2 dayw)
• Learning Outcome 8: Electric Field (recover 1 day)
• Learning Outcomes 7 - 8: Coulomb's Law and Electric Field (recover 3 days)
• Learning Outcomes 4-6: Charging Methods (recover 4-5 days)

If you are looking to transfer some time to other topic areas, we recommend eliminating outcomes 7 and 8. 


 

Science Reasoning Center

Force and interactions are a large part of the Next Generation Science Standards. Our Science Reasoning Center is packed with interactive activities that emphasize science reasoning skills in the context of content. Put another way, you will find numerous activities that lie at the intersection of a disciplinary core idea, a science and engineering practice, and a crosscutting concept. The Electrostatics section of our Science Reasoning Center included numerous activities that would be of interest to those using an NGSS curriculum as well as those using any Physics curriculum. Here are a few of our favorites:
 

1. Charge Interactions
   Questions target a student's ability to retrieve information from a body of text, to understand the design of an experiment, to draw conclusions that are consistent with observations, to make predictions based on a model, to identify the supporting evidence for a particular conclusion, and to predict the results of an additional trial in an experiment.
2. Sticky Tape Experiments
   Questions target a student's ability to identify the supporting evidence for a particular conclusion, to draw conclusions that are consistent with two or more data presentations, to make predictions based upon a model, to predict the results of an additional trial, and to understand the design of an experiment.
3. Energy Stored in Fields
   This NGSS-inspired task engages students in an analysis of two situations involving the storage of energy in electric and magnetic fields.

 

Teacher Presentation Pack

We probably say this a lot. But we think it is worth saying. Our Teacher Presentation Pack is a huge time-saver. For early-career and cross-over Physics teachers, it may also become a life saver. It includes a large collection of Slide Decks, animations, and graphics for use in your classroom. Once downloaded, you can modify and customize the Slide Decks as needed. Besides being highly organized slide decks to assist with your in-class presentations, most slides make great graphic organizers for preparing students for a Concept Builder or Minds On Phyiscs mission. They can also be placed on Google Drive for your students to view (provided it is password protected and not publicly accessible). Given the enormous value and relatively low cost, you have to ask yourself What am I waiting for? Learn more.



 

Also Available ...

Physics teachers may find the following for-sale tools to be useful supplements to our Lesson Plan and Pacing Guide section:

 

1. Task Tracker Subscription (annual purchase)
   A subscription allows teachers to set up classes, add students, customize online assignments, view student progress/scores, and export student scores. Task Tracker accounts allow your students to begin assignments in class or at school and to finish them at home. View our Seat and Cost Calculator for pricing details.
    
2. The Solutions Guide
   We publish a free curriculum with >200 ready-to-use Think Sheets for developing physics concepts. The Solutions Guide is a download containing the source documents, PDFs of source documents, and answers/solutions in MS Word and PDF format. An expanded license agreement is included with the purchase. (Cost: $25 download)
    
3. Teacher Presentation Pack
   This is a large collection of downloadable content packed with nearly 190 Microsoft PowerPoint slide decks, the corresponding Lesson Notes (as PDF and fully-modifiable MS Word format), about 170 animations (in .gif, .png, and .mp4 file formats), a countless number of ready-to-use images (including the original source documents that would allow for easy modification of those images), and a license that allows teachers to modify and use all the content with their classes on password-protected sites (such as course management systems).  (Cost: $40 download)
    
4. Question Bank
   We distribute a Question Bank that includes more than 9300 questions neatly organized according to topic. The Question Bank is the perfect tool for busy teachers or new teachers. Even if you don't use the website with your classes, the Question Bank will assist you in quickly putting together quizzes, tests and other documents with high-quality questions that target student's conceptions of physics principles. And if you do use The Physics Classroom website, the Question Bank is the perfect complement to the materials found at the website. (Cost: $25 download)