Content Reviewed: yes
AIG Reviewed: 7/31/12
Need Revisions (Y/N): Y
Content-no
Complete: content-yes
NCDPI -- AIG Instructional Resource: Background Information
Date Submitted: 7/5/12
Resource Title: Mapping an Electric Field
Subject Area/Grade Level (s):
Physics/ 9-12
Common Core/Essential Standard Addressed:
Phy.3.1.2 Explain the geometries and magnitudes of electric fields.
Time Frame 1 hour
Additional Standards Addressed:
(integration across topics, within or across disciplines)
Phy.3.1.5 Explain how differences in electrostatic potentials relate to the potential energy of charged objects.
Brief Description of Lesson/Task/Activity:
(include how this lesson/task/activity fits with a larger context)
Energy and forces and their connection are constant themes in physics. This activity introduces students to the connection between electric
force and electric potential. Students use a multimeter to plot equipotential lines between 2 parallel plates and then 2 small discs of charge
(similar to point charges). After collecting data, AIGs draw the electric field lines using given relationships between the two concepts. Analysis
questions draw attention to the relationships between electric forces, electric potential, and electric potential energy.
Type of Differentiation for AIGs (include all that apply)
 Enrichment
 Extension
 Acceleration
Adaptations for AIGs
 Content
 Process
 Product
Explanation of How Resource is Appropriate for AIGs
AIGs must connect several concepts to successfully complete this activity. A comprehensive approach to learning physics is extremely valuable
to all students but especially taps the ability of AIGs to think and integrate concepts. This activity coordinates force concepts, energy concepts,
electric fields, electric potential, electric potential energy, circuit design, and graphing techniques, all of which benefit complex thinking as
desired for AIGs.
Needed Resources/Materials
distilled water, wires with clips, a multimeter, DC power supply, two rectangular metal plates, plastic or glass container, grid paper, 2 metal coins
(pennies or quarters)
Sources (all sources must be cited)
http://www.youtube.com/watch?v=WcSSWN4Tnoo&feature=related
http://webphysics.davidson.edu/Course_Material/Py230L/efields/elecfields.htm
http://www.regentsprep.org/Regents/physics/phys03/afmap/default.htm
http://web.centre.edu/jason.neiser/Classes/Phy230Files/FieldMapping.pdf
TEACHER NOTES
Make sure that students are familiar with digital multimeters before this activity. Metal plates are simply any metal (copper is best, aluminum is
also good) with approximate length of 8 cm and height of 2 cm in a rectangular shape. Distilled water is best for this activity, but tap water can
usually work well. Coins serve as point sources, but copper wires of diameter of 3 to 5 mm can also be used if bent into the shape shown below.
Water in container
NCDPI AIG Curriculum Resource Outline
Describe processes, steps, and materials needed at each stage of the lesson/activity.
STAGE ONE: Engage
 Hook
 Prior knowledge
Instructional input
 Modeling
Description:
Introduce the concept of electric fields and electric field lines. This can be done by assigned textbook reading and/or using some simulations.
An excellent simulation can be found at http://phet.colorado.edu/en/simulation/charges-and-fields. Even more fun is Electric Field Hockey
found at http://phet.colorado.edu/en/simulation/electric-hockey. Don’t spend too much time on explanations as AIGs should pick up the idea
quickly from the activity. It is an important concept so the experience with mapping the fields s be valuable. Not sure what you want to say
here…please revise.
STAGE TWO: ELABORATE
 Guided and independent practice
 Guiding questions
Description:
Use the site at http://livephoto.rit.edu/LPVideos/equipot/ to show the main idea of the activity. Give the AIGs the activity sheet and the
materials to complete the activity. Make sure that they map the equipotential lines before drawing the electric field lines. Also, remind AIGs
that field lines are vectors and a direction must be indicated.
STAGE THREE: EVALUATE

Assessment
Description:
Use the questions in the activity to assess understanding. The questions and answers are given below. Can students also discuss when in the
real world this information is put to use? What applications does it have?
1. What is the difference between electric potential and electric potential energy?
Electric potential is the energy in Joules per Coulomb of charge. Electric potential is the total energy in Joules of a total amount of
charge.
2. When is the equation ∆V = Ed applicable? Please give an example of some key words in a problem that would justify the use of this
equation.
It applies when the Electric field does not change. If a problem says “uniform electric field” or “constant electric field” then this equation
can be used.
3. Equipotential line is a line on which the electric potential, V, is the same at every point. Suppose a test charge, q , is moved from point a
to point b on such a line, what is the change in electric potential energy ? Explain.
There is no change because the voltage stays the same.
4. A uniform electric field has magnitude E and is directed in the positive x direction. Suppose point a is at x = 1.6 m and that point b is at x
= 2.2 m, which point, a or b, is at the higher potential? Why? Point a is at the highest potential because the electric field always points
from high potential to low potential and as such it points from 1.6 m to 2.2 m (in the positive x direction).
TEACHER NOTES:
If you wish to print the grid paper rather than buy it from a science supply business then you can find some online at various URL’s such as
http://www.classroomjr.com/printable-graph-paper-and-grid-paper/ .
The fields from parallel plates and 2 oppositely charged points can be found in every physics book so that students can check their results.