Demonstrations explain the concepts of energy forms (sound, chemical, radiant [light], electrical, atomic [nuclear], mechanical, thermal [heat]) and states (potential, kinetic).
In this lesson, students will build a simple DC motor out of metal coat hangers, a 24-guage wire armature and field magnet, 14-guage wire brushes, and build the motor so that it rotates when connected to a 10-volt DC power supply. Students will understand the principles of operation of the DC motor, to include: induction of an electromagnetic field via current flowing through a conductor (electromagnetism), and become familiar with the notion that Forcetotal of the motor is proportional to charge, proportional to speed, proportional to the induced magnetic field (B), and dependent on the angles between the rotation of the armature in the field magnetism. Forcetotal = qv X B = (mv2/R), where q is the amount of charge, v is velocity of charge, B is the magnetic field strength, m is the mass of the charge, and R is the radius of the armature loop. Students will be able to solve one variable magnetism problems, describe how their motors operate, and write up a lab report on their findings. During the lab report, students will discuss how they got their motors to rotate faster than the initial trial after building it.
Background: students are familiar with static electricity, charge, and sparks. They also know about conservation of energy, forms of energy including potential energy, power, and work. Students will complete a variety of activities using breadboards, which will display various types of circuits and their effect on the flow of electricity.