Force Fields — Magnetic Forces

About this lesson

This lesson introduces students to magnetic forces. It begins by showing natural and industrial magnets of various shapes (lodestone, bar, U-shaped, cylindrical, horseshoe, magnetic needle). Students learn to distinguish magnetic materials (e.g., soft iron, cobalt, iron, nickel) from non-magnetic ones (e.g., gold, aluminum, copper, silver) through an experiment with a mixture of copper filings, iron filings, and sand. The lesson then explores properties of magnets: attraction is strongest at the poles, a freely suspended magnet aligns with Earth's magnetic poles, and dividing a magnet always produces new magnets with both north and south poles. The law of attraction and repulsion is stated: like poles repel, unlike poles attract. Finally, the concept of a magnetic field is introduced, represented by imaginary field lines that start from the north pole and end at the south pole, are denser near the poles, and do not intersect. Students are expected to recognize magnet shapes, differentiate materials, explore properties, conclude the law, recognize the magnetic field, and draw field lines for a single magnet and for opposite poles of two magnets.