Lesson 1. NetLogo Electric Potential (Pressure)

Neil Schmidgall
Physics
1-2 (45 minute) class period
General Physics
v4

Overview

This is an investigation into Electric Potential (Pressure) in one or more conductors with excess charge.

It will determine:

  1. how charges will distribute themselves in a conductor
  2. how Electric Potential (Pressure) depends on charge density
  3. how 2 metals in contact with equal Electric Potential (Pressure) have different amounts of Potential Energy (are capable of doing different amounts of work)

Standards

Computational Thinking in STEM
  • Data Practices
    • Creating Data
  • Modeling and Simulation Practices
    • Using Computational Models to Understand a Concept

Credits

Unit designed by Neil Schmidgall a teacher at Glenbrook South.

Acknowledgement

Unit designed by Neil Schmidgall a teacher at Glenbrook South.

Activities

  • 1. Part I:
  • 2. Part II:

Student Directions and Resources


This is an investigation into Electric Potential (Pressure) in one or more conductors with excess charge.

It will determine:

  1. how charges will distribute themselves in a conductor
  2. how Electric Potential (Pressure) depends on charge density
  3. how 2 metals in contact with equal Electric Potential (Pressure) have different amounts of Potential Energy (are capable of doing different amounts of work)

1. Part I:


  1. Put the number of positive charges at 50 and hit setup.
  2. Wait for the charges to show up on the screen. Hit go one time and record the Initial Electric Pressure.
  3. Hit the go button several times and watch what the charges do. Keep clicking on the go button until the graph for Electric Pressure levels off.
  4. Record the values from the Electric Pressure Monitor Window at the top of the Electric Pressure graph.
  5. Repeat with different numbers of charges and fill in the table below.


Question 1.1

Repeat with different numbers of charges and fill in the table below.



Question 1.2

What do like charges want to do naturally in a conductor?



Question 1.3

Does the Electric Pressure go up or down from the initial value as the go button is pressed?

  up
  down


Question 1.4

Imagine each charge creating an electric field around it. Do like charges naturally move in the direction of their neighbor’s electric field or opposite?



Question 1.5

Would you (an external non-conservative force) have to do positive or negative work to move like charges closer together?



Question 1.6

Would the charges have more Potential Energy or less Potential Energy if you force them closer together?



Question 1.7

How does increasing the amount of charge in a fixed space affect the Electric Pressure?

2. Part II:


  1. Put the number of positive charges @ 100 and hit Setup.
  2. Wait for the charges to show up on the screen.
  3. Set the “line-position” slider to 10 and click on the put-line button.
  4. Hit the go button until the Electric Pressure line levels off.
  5. Click on the fade-line button and hit the go button until the Electric Pressure line levels off.
  6. Record the values from the Monitor windows in the table below.


Question 2.1

Repeat with different “line-position” values and fill in the table below.



Question 2.2

Compare leveled off values after fade-line versus before fade-line for when “line-position” < 40.

How did Electric Potential change?



Question 2.3

How did the total PE change?



Question 2.4

How did number of charges to the left of the “line-position” compare to number of charges to the right?



Question 2.5

How did PE to the left of the “line-position” compare to PE to the right?



Question 2.6

Which side of the “line-position” is capable of doing more work?



Question 2.7

Since Electric Potential is measured in Joules/Coulomb (Volt), how is a “D” cell battery different from a “AA” battery if they are both 1.5 Volts?



Question 2.8

In the same circuit of lighting a bulb or running a motor, how would a “D” cell battery be different from a “AA” cell battery?