GCSE PHYSICS - MAGNETISM AND ELECTROMAG - LESSON 7 - magnets magnetising

How to Magnetize Steel Materials

Understanding Magnetic Domains

• The lesson begins with an introduction to magnetizing materials, specifically steel. At this point, the magnetic domains within a steel nail or bolt are randomly oriented, resulting in a net magnetic field of zero.

Methods of Magnetization

Rubbing with a Permanent Magnet

• One method to magnetize the steel object is by rubbing a permanent magnet along its side. This action causes the magnetic domains inside the material to gradually align with the magnetic field of the permanent magnet.

• After sufficient rubbing, the magnetic domains will align such that when the magnet is removed, the object retains its magnetism, exhibiting distinct North and South poles.

Tapping with a Hammer

• Another technique involves tapping the steel object with a hammer while it is in proximity to a magnetic field. This tapping assists in aligning the magnetic domains due to vibrations caused by impact.

• It’s important to note that while this method can induce some level of magnetism, it does not produce strong magnets; alignment depicted in diagrams is often more idealized than reality.

Using a Solenoid for Strong Magnetization

• The most effective method discussed for inducing strong magnetism involves using a solenoid. By placing the steel object inside and allowing current to flow through, a significant magnetic field is generated around it.

• As current flows through the solenoid, it creates an intense magnetic field that strongly aligns the internal domains of the core material. This results in robust magnetization where one end becomes North and another South pole.

Material Considerations