Electromagnetism Utilizing electricity to create and use magnetic fields

Electricity and Magnetism Relationship discovered in 1820 by Danish scientist Hans Christian Oersted Electricity and Magnetism are different parts of one force called the electromagnetic force Moving electric charges create a magnetic field

Solenoids & Electromagnets When a wire carrying a current is looped, the magnetic fields combine to make the wire act like a bar magnet The field through the center is very strong. Loop it more, it gets stronger

Solenoids & Electromagnets A coil of current-carrying wire that causes a magnetic field is called a solenoid Place a ferromagnetic (iron based) material in the middle of the coil…you have an electromagnet (This greatly increases the strength of the magnetic field produced by a solenoid)

Solenoids & Electromagnets Changing the current in the wire controls the strength and direction of the magnetic field produced The current can also be used to turn the magnetic field on and off. Scientists manipulate current and magnets when making devices we use every day

Solenoids & Electromagnets The strength of an electromagnet depends on: The current in the solenoid (more current  more strength) The number of loops in the coil (more loops  more strength) The type of material in the core

Electromagnetic Devices Electromagnets can take electrical energy (from the moving electrons in current) and change it into motion that can do work Electromagnetic devices thus change electrical energy into mechanical energy Door bells Electric motors Loudspeakers Galvanometers

Galvanometers Measure small amounts of current using a solenoid Used in gas gauges where a sensor in the gas tank reduces current as the tank gets low

Electric Motors Use an electromagnet to turn an axle When current flows, one side of the armature is pushed and the other is pulled Current continues to change direction, which causes the axle to spin

Electromagnets at Work!