Introduction

What do windshield wipers, CD players, DVD recorders, blenders, ice makers, laptops, and walking toys have in common?In fact, you can walk through your house and find many electric motors hidden in electrical devices, appliances, and toys in every room.You can detect the existence of a magnetic field and identify the north/south pole with a compass (which is basically a bar magnet mounted so that it can rotate), as shown in Figure 1, below.In summary, like poles (north-north or south-south) repel, opposite poles (north-south) attract.As you've probably seen, magnets are typically black, so there is no visible way to tell which end is north and which is south.The stronger the magnets, the more forceful the attraction / repulsion is between them.They all contain electric motors.Have you ever played with magnets?