Unit Plan 15 (Grade 8 Science): Magnetism & Electromagnets

Focus: Conduct investigations to provide evidence that electric currents can produce magnetic fields, using simple circuits, compasses, and electromagnets.

Grade Level: 8

Subject Area: Science (Physical Science • Forces & Interactions • Engineering Applications)

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

I. Introduction

Students explore the idea that electricity and magnetism are linked by investigating how electric currents create magnetic fields. They observe compasses deflecting near wires, paper clips sticking to electromagnets, and differences between permanent magnets and current-carrying coils. Rather than simply being told a rule, students design and conduct investigations that provide evidence that when current flows, a magnetic effect is produced—and when current stops, so does the magnetism. By the end of the unit, they can explain how electromagnets work and connect them to real-world technologies like motors, speakers, and MRI machines.

Essential Questions

• How are electric currents and magnetism connected?
• What evidence shows that an electric current can create a magnetic field?
• How can we design and conduct an investigation to show that magnetism appears only when current is flowing?
• How can changing current, number of coil turns, or core material affect the strength of an electromagnet?
• Where do we see electromagnets used in everyday technologies, and why are they useful compared to permanent magnets?

II. Objectives and Standards

Learning Objectives — Students will be able to:

1. Describe magnetism and magnetic fields qualitatively, including how they affect compasses and iron objects.
2. Construct simple circuits with current-carrying wires and coils and observe how they interact with compasses and small metal objects.
3. Plan and conduct an investigation to provide evidence that electric currents can produce magnetic fields, aligning with MS-PS2-5.
4. Systematically vary one or more factors (e.g., number of coil turns, amount of current, type of core material) and observe changes in magnetic effects (e.g., number of paper clips picked up, compass deflection).
5. Record, organize, and interpret data from their investigations to identify patterns linking current and magnetism.
6. Communicate an explanation using evidence that electric currents can create magnetic fields, and compare electromagnets with permanent magnets in terms of control and strength.

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

• MS-PS2-5 — Conduct an investigation to provide evidence that electric currents can produce magnetic fields.
  • In this unit, students build and test simple electromagnets and current-carrying wire setups, using compasses and iron objects to observe and measure magnetic effects when current flows.

Success Criteria — Student Language

• I can build a simple circuit and show that when current flows, there is a magnetic effect (compass deflects, paper clips are attracted).
• I can design and carry out an investigation that changes something about the current or coil and records how the magnetic effect changes.
• I can use data (like number of paper clips picked up or angle of compass deflection) to support my claim that electric currents produce magnetic fields.
• I can explain the difference between a permanent magnet and an electromagnet, and describe advantages of electromagnets.
• I can communicate my findings clearly, using terms like electric current, magnetic field, coil, and electromagnet correctly.