Unit Plan 14 (Grade 8 Science): Electric Forces & Charge

Focus: Ask questions about data to determine the factors that affect the strength of electric and magnetic forces, including amount of charge, distance, and orientation.

Grade Level: 8

Subject Area: Science (Physical Science • Forces & Interactions • Scientific Practices)

Total Unit Duration: 5 sessions (one week), 50–60 minutes per session

I. Introduction

Students are introduced to electric and magnetic forces as non-contact forces that can attract or repel. They observe everyday phenomena—static cling, charged balloons, and bar magnets—and analyze simple data sets showing how distance, amount of charge, and orientation affect the strength of these forces. Instead of immediately “learning rules,” students practice the scientific practice of asking questions from data, refining them from vague (“Why does this happen?”) to testable, specific questions (“How does doubling the distance change the strength of the magnetic force?”). By the end of the unit, students build a short “question portfolio” grounded in evidence from data sets and classroom investigations, aligned with MS-PS2-3.

Essential Questions

• What are electric and magnetic forces, and how are they similar to and different from gravitational and contact forces?
• What patterns in data suggest that distance, amount of charge, or orientation affect the strength of electric and magnetic forces?
• How can we ask better scientific questions when we look at tables, graphs, and observations about electric and magnetic interactions?
• What makes a testable, focused question that could guide a future investigation?
• Why is the skill of asking questions from data important for scientists and engineers?

II. Objectives and Standards

Learning Objectives — Students will be able to:

1. Describe electric forces and magnetic forces as non-contact forces that can be attractive or repulsive, depending on charge or pole.
2. Interpret simple data sets (tables, graphs, qualitative observations) showing how distance, amount of charge, number of rubs, or magnet orientation relates to force strength.
3. Generate descriptive and testable questions from data about factors that might affect force strength (e.g., “How does distance affect the pull between magnets?”).
4. Refine broad questions into more precise questions that identify variables and could be answered with further investigation.
5. Distinguish between questions about what happens, why it happens, and how we could test it, and prioritize questions that match the intent of MS-PS2-3.
6. Construct and present a short “Electric & Magnetic Forces Question Portfolio” containing multiple questions linked to specific pieces of data and patterns.

Standards Alignment — 8th Grade (NGSS-based custom)

• MS-PS2-3 — Ask questions about data to determine the factors that affect the strength of electric and magnetic forces.
  • In this unit, students examine tables, graphs, and classroom observations of electric and magnetic interactions, then generate and refine questions about how charge, distance, and orientation affect force strength.

Success Criteria — Student Language

• I can explain that electric and magnetic forces can act at a distance and can attract or repel.
• I can look at a data table or graph and describe patterns about how distance, charge, or orientation affects the strength of the force.
• I can write clear, testable questions that focus on how one factor (like distance or amount of charge) affects electric or magnetic forces.
• I can revise a vague question into a more specific, investigable question using evidence from data.
• I can present a set of questions and explain which data or patterns led me to each question.