Electromagnets Science Unit 1 Lesson 5 4 th Grade Miss Young

Making a Magnetic Field Wrapping a wire into a tight coil around something magnetic creates a strong magnetic force An electromagnet is a magnet that has coils of wire carrying a current of electricity around the iron core Electromagnets are temporary magnets –They only hold a magnetic force if an electrical current is running through the wire. Turn off the electricity it won’t work!

Controlling Electromagnets Turning off the electrical current will turn off the electromagnet 2 ways to make an electromagnet stronger: –Increase the coils of wire –Increase the electric current Switching the poles will switch the direction of the electromagnets poles

How are Electromagnets Used? Electromagnetism and Motion Doorbells and Speakers Electric Motors Generators

Electromagnets and Motion A magnetic coil with a permanent magnet can produce a turning motion…and sometimes a straight motion The electromagnet changes the energy stored in the battery into another type of energy made for motion called kinetic energy A relay switch (like a car starter) uses electricity in one circuit to close and switch in another circuit

Doorbells and Speakers Doorbells use metal rods inside wire coils When you push the button the rod goes inside the coil wire and produces electricity to make the doorbell ring. When you let go of the button the rod comes back out and stops the flow of electricity Speakers and microphones also use electromagnets by converting electrical energy to sound energy

Electric Motors Converts electric energy into kinetic energy Motors usually cause rotation or a spinning motion because the magnet inside is causing the N and S poles to constantly attract and repel eachother

Generators A machine that converts other forms of energy into electrical energy Examples: –Human kinetic energy –Gasoline power –Energy plants burn fuel to create steam –Wind power –Water power

Examples of Generators