Electricity (An Introduction)

ELECTRICITY  MAGNETISM Electric currents cause magnetism How can you tell? Compass needle moves when near electrical current - creating a magnetic field

What is an electromagnet? Electromagnet – a magnet made by coiling a wire wrapped around a piece of iron & running electricity through the wire.

ELECTROMAGNET Electromagnetism A magnet with a field produced by an electric current Electromagnetism a moving charge (electricity) produces a magnetic field More coils of wire= more current = stronger magnet Bigger battery = stronger magnet What’s going on? An electromagnet is a magnet that can be turned on and off. In this experiment, the battery is a source of electrons. When you connect the wire to the battery, the electrons flow through the wire. If there is not a complete circuit, the electrons will not flow. Electrons behave like little magnets and when they flow through a wire, they create a magnetic field, which turns the nail into a magnet that can pick up paper clips and staples!

electromagnet An electromagnet is a strong temporary magnet ( can be switched on & off  ) that uses electricity to produce magnetism.

Did you know you already use electromagnets ? Electromagnets are found in may devices. Doorbells, computers, audio speakers, and telephones have electromagnets in them. In “ steel recycling centers” a crane uses an electromagnet to pick up heavy loads of iron or steel. In some buildings, they are used to hold heavy fire doors open. In an emergency the electricity will be turned off ( because the magnet no longer works, the doors close blocking the spread of fire 

MAGNETISM  ELECTRICITY Moving magnet can generate electricity Electricity can produce magnetism. This also works the other way around. A magnet can produce electricity that’s how an energy station works. A coil of wire turns inside the magnetic field of a huge magnet. When the wire cuts across the magnetic field, electricity flows through the wire. moving a magnet in and out of a coiled wire created an electrical current without a battery.

Motors and Generators Electric Motor – a device that changes electric current into mechanical energy. Generator – a device that changes mechanical energy into electrical current in energy stations. A motor contains a coil of wire that can spin inside the magnetic field of a permanent magnet. Usually use moving magnets to create currents in coils of wire.

Electric Motors When the motor is switched on, electricity produces a magnetic field in the coil of wire. The coil becomes an electromagnet. The poles of this electromagnet are attracted & repelled by the poles of the permanent magnet. This cause the electromagnet to spin. The motion of the spinning coil can turn the blades of the blender or the fan.

Electric Motors Electric motor inside a fan contains a coil of wire & a permanent magnet. When the fan is turned on, the coil becomes an electromagnet. The poles of the electromagnet are attracted to the opposites poles of the permanent magnet, so the coil turns. To keep the coil moving, the direction of the electricity keeps changing. This causes the coil & the permanent magnet to alternately attract & repel.