Repeat with different numbers of charges and fill in the table below.
Unit Overview
Understanding Electrostatics through NetLogo modeling
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.
Underlying Lessons
- Lesson 1. NetLogo Electric Potential (Pressure)
- Lesson 2. Electrostatics with Point Charges
- Lesson 3. Electrostatics: Parallel Plates
Lesson 1 Overview
This is an investigation into Electric Potential (Pressure) in one or more conductors with excess charge.
It will determine:
- how charges will distribute themselves in a conductor
- how Electric Potential (Pressure) depends on charge density
- how 2 metals in contact with equal Electric Potential (Pressure) have different amounts of Potential Energy (are capable of doing different amounts of work)
Acknowledgement
Unit designed by Neil Schmidgall a teacher at Glenbrook South.
Lesson 1 Activities
- 1.1. Part I:
- 1.2. Part II:
1.0. Student Directions and Resources
This is an investigation into Electric Potential (Pressure) in one or more conductors with excess charge.
It will determine:
- how charges will distribute themselves in a conductor
- how Electric Potential (Pressure) depends on charge density
- how 2 metals in contact with equal Electric Potential (Pressure) have different amounts of Potential Energy (are capable of doing different amounts of work)
1.1. Part I:
- Put the number of positive charges at 50 and hit setup.
- Wait for the charges to show up on the screen. Hit go one time and record the Initial Electric Pressure.
- 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.
- Record the values from the Electric Pressure Monitor Window at the top of the Electric Pressure graph.
- Repeat with different numbers of charges and fill in the table below.
Question 1.1.1
Question 1.1.2
What do like charges want to do naturally in a conductor?
Question 1.1.3
Does the Electric Pressure go up or down from the initial value as the go button is pressed?
up
down
down
Question 1.1.4
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 1.1.5
Would you (an external non-conservative force) have to do positive or negative work to move like charges closer together?
Question 1.1.6
Would the charges have more Potential Energy or less Potential Energy if you force them closer together?
Question 1.1.7
How does increasing the amount of charge in a fixed space affect the Electric Pressure?
1.2. Part II:
- Put the number of positive charges @ 100 and hit Setup.
- Wait for the charges to show up on the screen.
- Set the “line-position” slider to 10 and click on the put-line button.
- Hit the go button until the Electric Pressure line levels off.
- Click on the fade-line button and hit the go button until the Electric Pressure line levels off.
- Record the values from the Monitor windows in the table below.
Question 1.2.1
Repeat with different “line-position” values and fill in the table below.
Question 1.2.2
Compare leveled off values after fade-line versus before fade-line for when “line-position” < 40.
How did Electric Potential change?
Question 1.2.3
How did the total PE change?
Question 1.2.4
How did number of charges to the left of the “line-position” compare to number of charges to the right?
Question 1.2.5
How did PE to the left of the “line-position” compare to PE to the right?
Question 1.2.6
Which side of the “line-position” is capable of doing more work?
Question 1.2.7
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 1.2.8
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?
Lesson 2 Overview
Teacher designed unit
Lesson 2 Activities
- 2.1. Getting familiar with the model
- 2.2. Part A: Source Charge
- 2.3. Part B: Point Charge
- 2.4. Part C: Distance
- 2.5. Part D: Equations
- 2.6. Part E: Conclusions about the Electric Field
2.0. Student Directions and Resources
A positive charge, Q, is located at the bottom center of the Netlogo World. This charge is creating an Electric Field in the space around it. Another electric charge, q, is shown near the center of the world positioned in this Electric Field. The green Force vector at the top shows the force on the charge, q, due to the field and the yellow field vector at the bottom shows the direction and magnitude of the electric field where the charge in the field, q, is located.
2.1. Getting familiar with the model
Hit Setup and Go for the model below. Move your cursor around in the space surrounding the positive Source Charge, Q, located at the bottom center of the NetLogo World. The green Force vector at the top shows the force, Fe, on the charge, q, due to the field, and the yellow field vector at the bottom shows the direction and magnitude of the Electric Field, E, where the charge in the field, q, is located. The values listed to the right of the World are recording values related to the situation set up in the World.
2.2. Part A: Source Charge
The values listed to the right of the World are recording values related to the situation set up in the World.
Find the effect on the Electrostatic Force value on the charge, q, and the Electric Field value at the position of the charge, q, if the source charge, Q, is altered. Take data by changing the value of the source charge, Q. Click on Setup to get the values to the right of the World.
Question 2.2.1
Record data from the values to the right of the world in the table below. Take at least 5 data points. Click on the green + in the bottom row to add more rows of data.
Question 2.2.2
Do a power regression on the data to determine the dependence of Electrostatic Force and Electric Field on the source charge, Q.
Electrostatic Force, Fe, is dependent on Q to what power?
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
-1.5
-1
-0.5
0
0.5
1
1.5
2
Question 2.2.3
Electric Field, E, is dependent on Q to what power?
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.3. Part B: Point Charge
The values listed to the right of the World are recording values related to the situation set up in the World.
Find the effect on the Electrostatic Force value on the charge, q, and the Electric Field value at the position of the charge, q, if the charge in the field, q, is altered. Take data by changing the value of the charge in the field, q. Click on Setup to get the values to the right of the World.
Question 2.3.1
Record data from the values to the right of the world in the table below. Take at least 5 data points. Click on the green + in the bottom row to add more rows of data.
Question 2.3.2
Do a power regression on the data to determine the dependence of Electrostatic Force and Electric Field on the point charge in the field, q. Electrostatic Force, Fe, is dependent on q to what power?
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
-1.5
-1
-0.5
0
0.5
1
1.5
2
Question 2.3.3
Electric Field, E, is dependent on q to what power?
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.4. Part C: Distance
The values listed to the right of the World are recording values related to the situation set up in the World.
Find the effect on the Electrostatic Force value on the charge, q, and the Electric Field value at the position of the charge, q, if the distance, r, of q from the source charge Q, is altered. Take data by changing the position of the charge, q, in the field.
Do this by
1) clicking on Setup,
2) clicking on Go, and
3) moving your mouse around in the World to change the location of the point charge.
Question 2.4.1
Record data from the values to the right of the world in the table below. Take at least 5 data points. Click on the green + in the bottom row to add more rows of data.
Question 2.4.2
Do a power regression on the data to determine the dependence of Electrostatic Force and Electric Field on the distances between charges, r.
Electrostatic Force, Fe, is dependent on r to what power?
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
-1.5
-1
-0.5
0
0.5
1
1.5
2
Question 2.4.3
Electric Field, E, is dependent on r to what power?
-2
-1.5
-1
-0.5
0
0.5
1
1.5
2
-1.5
-1
-0.5
0
0.5
1
1.5
2
2.5. Part D: Equations
Use the data that you have collected to write the equations of proportionality for force and electric field in the blanks below using Q, q, and r.
Question 2.5.1
It is fortunate for us that physics allows us to formulate relationships between variables (equations) given a moderately low number of data points. Insert the values in the table below that would satisfy the equation solving for Electrostatic Force using your previous results. k is a constant to make the relationship an equality.
Question 2.5.2
It is fortunate for us that physics allows us to formulate relationships between variables (equations) given a moderately low number of data points. Insert the values in the table below that would satisfy the equation solving for Electric Field using your previous results. k is a constant to make the relationship an equality.
Question 2.5.3
There is also a way to reason through the equations when knowing just the factor of change. For instance, if you double the charge, q, you just tested, can you predict the effect on force by reasoning through the equation you've found and determining what would happen if a doubling occurs, or a tripling, or a quadrupling? In other words, could you tell me what factor the force will change by given you are going to double the charge in the field? Make a prediction below by picking a factor by which the force, Fe, on charge, q, will change when the magnitude of the charge, q, is doubled.
2 to a power of 2
2 to a power of 1
2 to a power of 0.5
2 to a power of 0
2 to a power of -0.5
2 to a power of -1
2 to a power of -2
2 to a power of 1
2 to a power of 0.5
2 to a power of 0
2 to a power of -0.5
2 to a power of -1
2 to a power of -2
Question 2.5.4
Make a prediction below by picking a factor by which the force, Fe, on charge, q, will change when the magnitude of the source charge, Q, is doubled.
2 to a power of 2
2 to a power of 1
2 to a power of 0.5
2 to a power of 0
2 to a power of -0.5
2 to a power of -1
2 to a power of -2
2 to a power of 1
2 to a power of 0.5
2 to a power of 0
2 to a power of -0.5
2 to a power of -1
2 to a power of -2
Question 2.5.5
Make a prediction below by picking a factor by which the force, Fe, on charge, q, will change when the distance, r, between charges, q and Q, is doubled.
2 to a power of 2
2 to a power of 1
2 to a power of 0.5
2 to a power of 0
2 to a power of -0.5
2 to a power of -1
2 to a power of -2
2 to a power of 1
2 to a power of 0.5
2 to a power of 0
2 to a power of -0.5
2 to a power of -1
2 to a power of -2
Question 2.5.6
Make a prediction below by picking a factor by which the electric field, E, at the location of charge, q, will change when the magnitude of the charge, q, is doubled.
2 to a power of 2
2 to a power of 1
2 to a power of 0.5
2 to a power of 0
2 to a power of -0.5
2 to a power of -1
2 to a power of -2
2 to a power of 1
2 to a power of 0.5
2 to a power of 0
2 to a power of -0.5
2 to a power of -1
2 to a power of -2
Question 2.5.7
Make a prediction below by picking a factor by which the electric field, E, at the location of charge, q, will change when the magnitude of the source charge, Q, is doubled.
2 to a power of 2
2 to a power of 1
2 to a power of 0.5
2 to a power of 0
2 to a power of -0.5
2 to a power of -1
2 to a power of -2
2 to a power of 1
2 to a power of 0.5
2 to a power of 0
2 to a power of -0.5
2 to a power of -1
2 to a power of -2
Question 2.5.8
Make a prediction below by picking a factor by which the electric field, E, at the location of charge, q, will change when the distance, r, from the source charge, Q, is doubled.
2 to a power of 2
2 to a power of 1
2 to a power of 0.5
2 to a power of 0
2 to a power of -0.5
2 to a power of -1
2 to a power of -2
2 to a power of 1
2 to a power of 0.5
2 to a power of 0
2 to a power of -0.5
2 to a power of -1
2 to a power of -2
2.6. Part E: Conclusions about the Electric Field
Question 2.6.1
Click on Setup in the model above. The gray lines in the space are manmade constructs called electric field lines. What is the only factor that changes the number of lines, and therefore the angular spacing between lines, in the area where the field is located?
Question 2.6.2
How can you determine the relative strength of the electric field compared to other locations by examining just the lines and their relationship to each other?
Question 2.6.3
How does changing the point charge, q, value in the field affect the electric field, E, created by the source charge?
Question 2.6.4
How does changing the point charge, q, in the field from positive to negative affect the magnitude and direction of the force vector on that charge, q?
Lesson 3 Overview
Learn how an electric field is created between parallel plates connected across a charged source.
Lesson 3 Activities
- 3.1. None
- 3.2. Part A: Electric Field Lines
- 3.3. Part B: Point Charge
- 3.4. Part C: Target Shoot with a Charge stream.
- 3.5. Part D: Connections
3.0. Student Directions and Resources
Use a NetLogo model to investigate electrostatics.
3.1. None
When you hit setup the following characteristics update:
1. E-field Lines
2. Parallel Plate colors
When you hit setup and go the following characteristics update:
1. E-field Value and E-field vector
2. Force Value and Force vector
3. Charge in the field value and color of charge
4. Mass of the charge in the field and size of the charge
The positive plate and positive charge in the model will be Red. The negative plate and negative charge in the model will be Blue.
3.2. Part A: Electric Field Lines
When you hit setup the following characteristics update:
1. E-field Lines
2. Parallel Plate colors
When you hit setup and go the following characteristics update:
1. E-field Value and E-field vector
2. Force Value and Force vector
3. Charge in the field value and color of charge
4. Mass of the charge in the field and size of the charge
The positive plate and positive charge in the model will be Red. The negative plate and negative charge in the model will be Blue.
Question 3.2.1
Draw an arrow on the lines showing the direction of the electric field, E.
Note: Draw your sketch in the sketchpad below
Question 3.2.2
Click go in the model. Move the charge around to see how the electric field, E, value depends on the position of the point charge. Indicate where the electric field between plates is the strongest. If there is no variation in field strength, use the TEXT tool to say that in the field.
Note: Draw your sketch in the sketchpad below
Question 3.2.3
Click go in the model. Move the charge around to see how the electrostatic force, Fe, value depends on the position of the point charge. Indicate where the electrostatic force on the point charge between plates is the strongest. If there is no variation in force, use the TEXT tool to say that in the field.
Note: Draw your sketch in the sketchpad below
3.3. Part B: Point Charge
When you hit setup the following characteristics update:
1. E-field Lines
2. Parallel Plate colors
When you hit setup and go the following characteristics update:
1. E-field Value and E-field vector
2. Force Value and Force vector
3. Charge in the field value and color of charge
4. Mass of the charge in the field and size of the charge
The positive plate and positive charge in the model will be Red. The negative plate and negative charge in the model will be Blue.
Question 3.3.1
Hit setup and go. Compare an equivalent magnitude chargeCoefficient < 0 vs chargeCoefficient > 0. What happened to the electric field value when this was done?
Question 3.3.2
Determine what variable(s) change the electric field value, E. Select them below.
Field Strength
Charge Value
Sign on the Charge
Position in the field between plates
Charge Value
Sign on the Charge
Position in the field between plates
Question 3.3.3
Determine what variable(s) change the electric force, Fe, on the point charge. Select them from the list below.
Field Strength
Charge Value
Sign on the Charge
Position in the field between plates
Charge Value
Sign on the Charge
Position in the field between plates
3.4. Part C: Target Shoot with a Charge stream.
When you hit setup the following characteristics update:
1. E-field Lines
2. Parallel Plate colors
When you hit setup and go the following characteristics update:
1. E-field Value and E-field vector
2. Force Value and Force vector
3. Charge in the field value and color of charge
4. Mass of the charge in the field and size of the charge
The positive plate and positive charge in the model will be Red. The negative plate and negative charge in the model will be Blue.
In the current setup the force on the point charge is either right or left depending on electric field direction and charge. We want to introduce a stream of charges moving upward with initial velocity, chargeVelY, from the bottom center between the plates. Turn on the ChargeStream switch followed by setup and go. Change variable values to get a path that is not straight up the screen.
Question 3.4.1
Describe the shape of the path the charges take as they move from the bottom to the top of the screen if there is a y-velocity and a force in the perpendicular x-direction only.
Question 3.4.2
What part of physics that we studied in semester 1 does this remind you of? Be fairly specific.
Question 3.4.3
In the table below set up values for mass, chargeCoefficient, chargeExponent, chargeVelY, and strength that will allow your stream to hit the numbered targets at the top.
3.5. Part D: Connections
1. E-field Lines
2. Parallel Plate colors
When you hit setup and go the following characteristics update:
1. E-field Value and E-field vector
2. Force Value and Force vector
3. Charge in the field value and color of charge
4. Mass of the charge in the field and size of the charge
The positive plate and positive charge in the model will be Red. The negative plate and negative charge in the model will be Blue.
In the current setup the force on the point charge is either right or left depending on electric field direction and charge. We want to introduce a stream of charges moving upward with initial velocity, chargeVelY, from the bottom center between the plates. Turn on the ChargeStream switch followed by setup and go. Change variable values to get a path that is not straight up the screen.
Question 3.5.1
If the stream of charges is hitting target 1 and you want to hit target 3, choose All that Apply from the statements below that would cause this.
Increase mass.
Decrease mass.
Increase chargeVelY.
Decrease chargeVelY.
Increase the magnitude of the charge.
Decrease the magnitude of the charge.
Change the charge from positive to negative
Change the charge from negative to positive
Increase the electric field value in the same direction.
Decrease the electric field value in the same direction.
Change the direction of the electric field vector.
Decrease mass.
Increase chargeVelY.
Decrease chargeVelY.
Increase the magnitude of the charge.
Decrease the magnitude of the charge.
Change the charge from positive to negative
Change the charge from negative to positive
Increase the electric field value in the same direction.
Decrease the electric field value in the same direction.
Change the direction of the electric field vector.
Question 3.5.2
If the stream of charges is hitting target 1 and you want to hit target 7, choose All that Apply from the statements below that would cause this.
Increase mass.
Decrease mass.
Increase chargeVelY.
Decrease chargeVelY.
Increase the magnitude of the charge.
Decrease the magnitude of the charge.
Change the charge from positive to negative
Change the charge from negative to positive
Increase the electric field value in the same direction.
Decrease the electric field value in the same direction.
Change the direction of the electric field vector.
Decrease mass.
Increase chargeVelY.
Decrease chargeVelY.
Increase the magnitude of the charge.
Decrease the magnitude of the charge.
Change the charge from positive to negative
Change the charge from negative to positive
Increase the electric field value in the same direction.
Decrease the electric field value in the same direction.
Change the direction of the electric field vector.
