Mapping a Magnetic Field

Introduction

The region around a magnet where magnetic forces can be detected is called a magnetic field. All magnets, no matter what their shape, have two poles labeled north and south. When two like poles are brought near each other (i.e. north and north or south and south), they repel each other. When two unlike poles are brought together, they are attracted. The forces of repulsion and attraction are present because of the magnetic field that completely surrounds the magnet. The magnetic field lines around a bar magnet form a similar pattern to the magnetic field lines around the Earth. They extend out from the North Pole, and then curve back into the South Pole. The field lines are more concentrated near the poles of the magnet so the magnetic field is said to be stronger near the poles. In this activity, you will use a Magnetic Field Sensor to map the magnetic field along a bar magnet. You will use a simple robot to do the actual data collection.

Objectives

In this experiment, you will

• Use a Magnetic Field Sensor and NXT to map the magnetic field along a bar magnet.
• Build a robotic device to collect data.
• Make conclusions about the magnetic field at various points on a bar magnet.