How Does an Electromagnet Work?

S5P3d. Compare a bar magnet to an electromagnet

What is a Magnet?

• An object that attracts certain metals, mainly iron• Magnetism decreases with distance from an object•Permanent magnets- keep their magnetism for a long time•Temporary magnets- lose their magnetism after a short time

Magnetic FieldsThe space in which a magnetic force can act is called a magnetic field.

Magnetic Poles- two areas of on a magnet in which the magnetic force is the greatest.

The Earth as a MagnetThe Earth behaves like a giant sized bar magnet. The center of the Earth is made up of iron. When the Earth spins, the iron particles line up creating a gigantic magnetic field.

Electricity and Magnetism

•Electricity can produce magnetism•Magnetism can produce electricity•Together, magnetism and electricity, can produce energy of motion

•An electromagnet is a strong temporary magnet that uses electricity to produce magnetism. You use them everyday in blow dryers and video games.

How Does Electricity Produce Magnetism?

-An electric current passes through a wire or other conductor-The current produces a weak magnetic field around the wire-If the wire is wrapped around iron, the iron becomes magnetized-This makes the magnetic field stronger

Using ElectromagnetsMagnets Electromagnets

Attract materials made of iron

Attract materials made of iron

Have magnetic fields Have magnetic fields

Magnetic force can be controlled

Electromagnets• Increasing the number of wire coils or the amount of current through coils increases the STRENGTH • Can be small and strong• Can be turned on and off• Cranes, MRIs, and the Bullet Train are useful electromagnets•Electromagnets are in blenders, computers, and doorbells

Brainpop- Electromagnets

MotorsA motor is a device that changes electrical energy into energy of motion. They contain a permanent magnet and an electromagnet.

“When a motor is turned on, electric current passes through a wire wrapped around an iron core. The magnetic field of this electromagnet interacts with the magnetic field of the permanent magnet. The like poles of each magnet repel each other and the unlike pole attract each other, producing motion.”

Generating ElectricityBrainpop- Electomagnetic Induction

Generator – a device that uses magnetism to convert energy of motion into electrical energy

• giant generators make electricity we use• have powerful permanent magnets and huge coils of wire• current is produced when the coils move across the magnetic field• stronger magnet or more coils increases amount of electricity made• energy to move coils comes from burning coal, nuclear fuels, steam, falling water, or blowing wind

Electromagnets

Complete a Venn diagram comparing a bar magnet with

an electromagnet.