What Are They? – A permanent magnet is made from a substance that is magnetized and that has its own permanent and persistent magnetic field. An electromagnet, on the other hand, is temporary.
QUESTIONS: What Are They? – Which of the following is NOT part of an electromagnet?
How to Make an Electromagnet – Many appliances that we use every day contain electromagnets, usually hidden inside the device. An electronic door lock contains an electromagnet that opens the lock mechanism.
QUESTIONS: How to Make an Electromagnet – What happens if you remove the source of electricity from an electromagnet?
Solenoids – A solenoid is a coil of wire that is used to create an electromagnet. The diameter of a solenoid is much smaller than its length. When a solenoid is wound around a central iron core (piston) and attached to a source of electricity, the solenoid generates a magnetic field, so that it acts like a permanent (bar) magnet.
QUESTIONS: Solenoids – When does a solenoid act like a permanent magnet?
Uses of Electromagnets – An electromagnet is useful because the magnetic field can be controlled. It can be made stronger or weaker by increasing or decreasing the electric current.
QUESTIONS: Uses of Electromagnets – Name three things mentioned in the article in which you will find the type of electromagnet which applies force and moves something.
History of Electromagnets – Danish scientist Hans Christian Orsted was the first to discover the relationship between electric current and magnetism. While giving a lecture in April of 1820, he notices that the needle of a compass moving away from magnetic north as an electric current from a battery was switched on an off.
QUESTIONS: History of Electromagnets – The scientist who developed a mathematical formula to represent the forces between conductors carrying currents was who?
Joseph Henry's Eletromagnet – Henry's electromagnet was the strongest that had ever been built. It also demonstrated that the electromagnet is best built differently depending on how many batteries will be attached to it.
QUESTIONS: Joseph Henry's Electromagnet – What did Henry's electromagnet prove about how to build an electromagnet with respect to how many batteries would be attached to it?
Ohmic Losses and Inductive Voltage Spikes – Ideally, all the energy in an electrical circuit would remain in the circuit, but in reality, some energy in an electrical circuit is lost as heat. In physics, resistance is measured in units called ohms.
QUESTIONS: Ohmic Losses and Inductive Voltage Spikes – Which of the following is NOT a way to control inductive voltage spikes?
Cyclotron Explained – A cyclotron is a device used to accelerate charged particles to high energy levels. The principle behind it is that a charged particle moving normally near a magnetic field is acted on by a magnetic Lorentz force which causes it to move in a circular path.
QUESTIONS: Cyclotron Explained – What are the hollow metal cylinders in a cyclotron called?
Magnetic Levitation Trains – A maglev train uses the force of electromagnetism to both levitate a train above its tracks and to propel it forward. Here’s how it works.
QUESTIONS: Magnetic Levitation Trains – What is a maglev?
Magnets and Motors – Electric motors create magnetic fields with electric current flowing through a coil. This magnetic field then causes a magnetic force that generates physical movement (spinning).
QUESTIONS: Magnets and Motors – If cars powered by permanent magnets become a practical reality, why would that be beneficial?