NGSS Performance Expectations

This unit primarily addresses high school NGSS standards in HS-PS2: Motion and Stability: Forces and Interactions and HS-PS3: Energy. Every section below maps to at least one Performance Expectation, Science & Engineering Practice, Disciplinary Core Idea, and Crosscutting Concept.

HS-PS2-4 HS-PS3-5 Developing Models PS2.B / PS3.C Cause & Effect

Electrostatics and the American Experiment

Benjamin Franklin, lightning, charge, and the revolutionary power of scientific thinking

1. Historical Introduction to Electrostatics

Physics, philosophy, and religion have often overlapped in meaningful ways. In the 1700s, lightning was still viewed by many people as mysterious, supernatural, or even divine. Benjamin Franklin’s work in electrostatics helped move the explanation of lightning from fear and mystery toward evidence, experiment, and physical law.

Franklin was not simply a scientist. He was a printer, writer, inventor, businessman, diplomat, and revolutionary. As the son of a candle and soap maker with limited formal schooling, Franklin became a symbol of the self-made person. His rise helped shape the image of the ordinary individual using knowledge, discipline, and practical intelligence to make a mark on the world.

His work in electricity gave him credibility in Europe. His work as a printer, propagandist, and diplomat helped fuel the American Revolution. Franklin’s life shows how science, communication, politics, and economics can become deeply connected.

2. What Is Electrostatics?

Electrostatics is the study of electric charge at rest. Before students analyze full circuits, current, resistance, and capacitors, they need to understand what charge is and why separated charge can create forces, energy differences, and motion.

Core Ideas

• Objects can become charged by gaining or losing electrons.
• Like charges repel and opposite charges attract.
• Charge can be transferred by contact.
• Charge can be redistributed without contact through induction.
• Electric potential difference, or voltage, describes energy per unit charge.

3. Franklin’s Model of Electricity

Franklin proposed that electricity behaved like a kind of invisible fluid. While modern physics explains electricity through particles, fields, and charge interactions, Franklin’s model was powerful because it gave people a way to reason about charge transfer and conservation.

Franklin’s Lasting Contributions

• He helped popularize the terms positive and negative charge.
• He argued that electrical effects could be investigated experimentally.
• He connected lightning to electrical discharge.
• He developed the lightning rod as a practical application of electrostatics.

4. Franklin, Lightning, and the Kite Experiment

Franklin’s famous kite experiment is one of the best-known stories in the history of science. The basic idea was to show that storm clouds carried electrical charge. A wet string, a key, and a conducting path allowed charge from the storm environment to be detected.

Why the Experiment Mattered

The kite experiment mattered because it connected a frightening natural event to a physical process that could be studied, predicted, and controlled. Lightning was no longer only a symbol of divine anger or mystery. It became evidence of charge separation and electrical discharge in the atmosphere.

5. Lightning Rods and Public Reaction

Franklin’s lightning rod was a practical invention based on electrostatics. A conducting rod attached to a building gives charge a safer path to the ground. Instead of allowing lightning to pass through wood, brick, or people, the rod directs the electrical discharge into Earth.

This invention created public debate. Some people welcomed it as a life-saving application of science. Others objected because they believed lightning was an act of God that humans should not interfere with. This disagreement reveals an important historical shift: scientific explanation was beginning to challenge older forms of authority.

6. Electrostatics and Revolution

Franklin’s scientific reputation made him famous in Europe before the American Revolution. When he later served as a diplomat in France, his image as a philosopher, scientist, and practical genius helped him gain attention and respect.

Franklin also understood the power of communication. Through printing, writing, satire, and public argument, he helped shape colonial identity. His scientific work and political work both depended on the same habit of mind: question inherited explanations, gather evidence, communicate clearly, and act.

7. Inquiry Assignment — Stealing God’s Thunder

In this inquiry, you will investigate how Franklin’s work with electricity influenced science, religion, public opinion, and the American Revolution. Your goal is not to write a simple biography. Your goal is to explain how scientific ideas can change culture.

Research Questions

8. Electrostatics Diagram Tasks

Create labeled diagrams and written explanations for each process below. Each explanation should connect the diagram to force, energy, or charge movement.

9. Historical Reflection Essay

Write a 2–3 page response to the following prompt:

Your response should include:

• At least three historical sources
• An explanation of Franklin’s work in electrostatics
• A discussion of Enlightenment thinking
• A connection to the American Revolution
• Your own argument about why Franklin’s work mattered

10. Suggested Sources

• The Franklin Institute — Franklin’s Kite and Key Experiment
• The Franklin Institute — Franklin’s Lightning Rod
• Library of Congress — Benjamin Franklin: Business and Science
• Library of Congress — Benjamin Franklin Papers

11. Assessment Rubric

12. Closing Thought

Franklin’s work with electricity helped people see that nature could be investigated rather than feared. That shift mattered far beyond physics. It helped support a larger Enlightenment belief that human beings could use reason to improve society.

The question remains important today: when scientific understanding changes, how should society change with it?

HS-PS2-4 HS-PS3-5 HS-PS2-5 Planning Investigations PS2.B Cause & Effect

Electrostatics Demonstrations Companion Guide

Charge, induction, electric fields, and the foundations of electricity through classroom demonstrations.

1. Core Vocabulary and Concepts

These demonstrations are designed to make invisible electric interactions visible. As you watch each demonstration, focus on where charge is moving, where charge is separating, and what evidence shows that an electric field is present.

2. Demonstration: Charging by Induction

In charging by induction, a charged object causes electrons in another object to move without touching it directly. This shows that electric forces can act through space.

3. Demonstration: Van de Graaff Generator

A Van de Graaff generator uses a moving belt to transport charge onto a metal dome. Because the dome is a conductor, excess charge spreads over its outer surface.

4. Demonstration: Franklin’s Bells

Franklin’s bells demonstrate charge transfer and repeated motion caused by electrostatic attraction and repulsion. A small conducting ball moves between two oppositely charged bells.

5. Demonstration: Faraday’s Ice Pail

Faraday’s ice pail experiment shows how charge behaves on conductors. When a charged object is lowered into a metal container, charge redistributes through the conducting surface.

6. Demonstration: Lenz’s Law

Lenz’s Law describes how induced currents oppose changes in magnetic flux. Although this demonstration belongs to electromagnetism rather than pure electrostatics, it shows an important extension: moving charge can create magnetic effects, and changing magnetic fields can cause charge to move.

7. Reflection Questions

HS-PS2-4 HS-PS3-5 HS-PS3 Using Math PS2.B / PS3.B / PS3.C Systems & Models

Foundations of Electricity and Circuits

A physics-centered primer connecting charge, force, fields, voltage, current, capacitance, resistance, and circuit analysis.

What You Should Be Able To Do

• Explain electric charge as a conserved property of matter.
• Use Coulomb’s Law to calculate the force between point charges.
• Interpret electric fields as force per unit positive test charge.
• Distinguish electric potential energy from electric potential, or voltage.
• Use capacitance to describe charge storage and energy storage.
• Use current, voltage, and resistance correctly in Ohm’s Law.
• Analyze series, parallel, and series–parallel resistor circuits.
• Compare equivalent resistance methods with Kirchhoff’s loop and junction laws.
• Recognize when a circuit can be simplified and when Kirchhoff’s Laws are the better tool.

Glossary of Electricity Terms

1. Electric Charge

HS-PS2-4 Using Math PS2.B Patterns

Electric charge is the starting point for all electrical phenomena. Matter contains positive protons and negative electrons. In most everyday charging processes, electrons are the particles that move from one object to another.

A neutral object has equal amounts of positive and negative charge. A negatively charged object has excess electrons. A positively charged object has lost electrons.

2. Electric Force and Electric Fields

HS-PS2-4 HS-PS3-5 Using Math / Developing Models PS2.B / PS3.C Cause & Effect

Charged objects exert forces on one another. Coulomb’s Law gives the size of the force between two point charges. The force increases with the size of each charge and decreases with the square of the distance between them.

The electric field shifts our attention from “one charge pushing another charge” to “a charged object changing the space around it.” If a test charge is placed in that space, it experiences a force.

3. Electric Potential Energy, Electric Potential, and Voltage

HS-PS3-5 HS-PS3 Developing Models PS3.C Energy & Matter

Electric force describes pushes and pulls. Electric potential describes energy. A charge in an electric field can have electric potential energy, just as a mass held above the ground has gravitational potential energy.

Voltage is not the same thing as energy. Voltage is energy per unit charge. A 9 V battery gives \(9\ \text{J}\) of energy to each coulomb of charge that moves through it.

4. Capacitance and Stored Electrical Energy

HS-PS3-5 Developing Models PS3.C Systems & Models

A capacitor stores charge by separating positive and negative charge on two conductors. The simplest model is two parallel plates separated by an insulating material or air gap.

The battery does work to separate charge. That energy is stored in the electric field between the plates.

5. Current, Resistance, and Ohm’s Law

HS-PS3 Using Math PS3.B Energy & Matter

Current is the rate of charge flow through a cross-section of a wire. Resistance describes how much a material or component opposes that flow.

A resistor does not destroy charge. Instead, it converts electrical energy into thermal energy, light, or another form. In a light bulb, electrical energy becomes thermal energy and visible light.

6. Series Circuits

HS-PS3 Using Math PS3.B Systems & Models

In a series circuit, components are connected in a single path. Since there is only one path, the current is the same through each resistor. The voltage supplied by the battery is divided across the resistors.

7. Parallel Circuits

HS-PS3 Using Math PS3.B Systems & Models

In a parallel circuit, components are connected across the same two points. Each branch receives the same voltage, but the current splits among the branches.

8. Series–Parallel Circuits

HS-PS3 Using Math PS3.B Systems & Models

Many real circuits are combinations of series and parallel sections. The key is to simplify one piece at a time. Start with the most obvious series or parallel group, replace it with an equivalent resistance, and repeat until the circuit reduces to one total resistance.

9. Kirchhoff’s Laws

HS-PS3 Using Math PS3.B Energy & Matter

Equivalent resistance works beautifully for circuits that can be reduced into obvious series and parallel groups. But not all circuits simplify cleanly. Kirchhoff’s Laws are more general because they come directly from conservation laws.

10. Equivalent Resistance vs. Kirchhoff’s Loop Method

These two methods often produce the same result, but they represent different ways of thinking.

Side-by-Side Example: Same Circuit, Two Methods

A \(12\ \text{V}\) battery is connected to a \(2\ \Omega\) resistor and a \(4\ \Omega\) resistor in series.

Side-by-Side Example: Series–Parallel Circuit

A \(12\ \text{V}\) battery is connected to a \(4\ \Omega\) resistor in series with two \(6\ \Omega\) resistors in parallel.

11. Practice Problems

12. Closing Connection

Electrostatics and circuits are not separate topics. Electrostatics explains why charges exert forces and why separated charge stores energy. Circuits explain what happens when charges are given a continuous path and a maintained potential difference. The same ideas — charge, force, field, energy, and conservation — connect the spark from a Van de Graaff generator to the current flowing through a resistor network.

HS-PS3 HS-PS3-5 Planning Investigations Analyzing Data PS3.B / PS3.C Systems & Models

Circuits Exploration Inquiry

A guided investigation of charge movement, voltage, current, resistance, capacitance, and circuit design using simulation, prediction, measurement, and physical construction.

1. Built-In Circuit Simulator

Use the simulator below to plan your circuit before building it physically. The goal is not to “play until it works.” The goal is to create a prediction, test the prediction, and then explain any differences between your model and your measurements.

2. Safety Expectations

1. Use power supplies at \(9\text{ V}\) or less unless instructed otherwise.
2. Check component tolerances before powering bulbs, LEDs, capacitors, and resistors.
3. Design and predict on paper or in the simulator before powering a circuit.
4. Turn off and disconnect power before modifying any physical circuit.
5. Keep fingers out of live circuits when measuring with a multimeter.
6. Remember that capacitors can hold charge after the circuit is off.
7. Discharge capacitors through a resistor, not through your body or a direct short.
8. Do not leave circuits powered longer than necessary.
9. Observe capacitor polarity carefully. Incorrect polarity can cause failure or popping.

3. Learning Goals

4. Required Inquiry Workflow

Each challenge must follow the same cycle. This is the heart of the assignment.

5. Circuit Challenges

6. Final Report Requirements

Your final report should read like an organized technical narrative, not a list of answers. It should explain what you tried, what you predicted, what happened, and how physics explains your observations.

Required Report Sections for Each Challenge

1. Goal: What were you trying to create, test, or verify?
2. Prediction: What did you calculate or expect before building?
3. Diagram: Include a clean circuit diagram with labels.
4. Simulation: Explain what happened in the simulator.
5. Physical Build: Include a photo of the completed physical circuit.
6. Measurements: Include voltage, current, resistance, time, or brightness observations as appropriate.
7. Analysis: Tie observations back to equations and concepts.
8. Revision: Explain what changed between your first attempt and final circuit.

7. Rubric

Constructing Explanations Analyzing Data Systems & Models

The main circuit challenges are scored on the quality of the circuit, modeling, explanation, and depth of inquiry. The final report is scored separately for evidence, organization, and clarity.

Challenge Categories

• Ohm’s Law and equivalent resistance circuits
• Step-down voltage divider
• Mini-bulb with switch and button
• RC time charging and discharging
• Series and parallel bulbs
• Switchable capacitor charge/discharge circuit

Final Report: 25 Points

8. Final Reflection