MAGNETISM LESSON PLAN: J S 2 E-NOTE 3RD TERM
BASIC SCIENCE
J S 2 3RD TERM
By the end of the lesson, students should be able to:
- Differentiate between magnetic material and non-magnetic materials
- Describe poles, magnetic flux and field of a magnet.
- State magnetic laws
- Highlight ways of demagnetizing a bar magnet.
WHAT IS MAGNETISM
Magnetism is a fundamental force of nature that manifests as the attraction or repulsion between objects with magnetic properties. It arises from the movement of charged particles, typically electrons, within atoms. When these charged particles align in a particular way, they generate a magnetic field around the object.
Magnetism is a fascinating aspect of physics that deals with the interactions of magnetic fields and magnetic materials. At its core, magnetism arises from the movement of charged particles, typically electrons, within atoms. When these particles align in a particular way, they create a magnetic field.
THERE ARE TWO TYPES OF MAGNETISM:
Permanent Magnetism: This type of magnetism is exhibited by materials that retain their magnetic properties even after the removal of an external magnetic field. Examples include iron, cobalt, and nickel.
Temporary Magnetism: Some materials can be temporarily magnetized when placed in an external magnetic field. When the external field is removed, these materials lose their magnetism. Examples include soft iron and electromagnets.
DIFFERENTIATE BETWEEN MAGNETIC MATERIAL AND NON-MAGNETIC MATERIALS
Magnetic Materials: These are materials that are attracted to a magnet and can be magnetized themselves. Examples include iron, nickel, cobalt, and their alloys.
Non-Magnetic Materials: These are materials that are not attracted to a magnet and cannot be magnetized. Examples include wood, plastic, glass, and most metals like aluminum and copper.
DESCRIPTION OF POLES, MAGNETIC FLUX, AND FIELD OF A MAGNET
POLES: A magnet has two poles, known as the north pole and the south pole. These poles are where the magnetic field lines converge (north pole) or diverge (south pole). Opposite poles attract each other, while like poles repel each other.
MAGNETIC FLUX: Magnetic flux is a measure of the total magnetic field passing through a given area. It is represented by the symbol Φ (phi) and is measured in units of Weber (Wb) or Tesla meter squared (T·m²).
MAGNETIC FIELD: The magnetic field of a magnet is the region around the magnet where magnetic forces are exerted. It is represented by magnetic field lines, which are directed from the north pole to the south pole outside the magnet and from the south pole to the north pole inside the magnet.
STATEMENT OF MAGNETIC LAWS:
Some fundamental magnetic laws include:
Gauss’s Law for Magnetism: The total magnetic flux through a closed surface is zero.
Ampère’s Law: The magnetic field induced around a closed loop is proportional to the electric current passing through the loop.
Faraday’s Law of Electromagnetic Induction: A changing magnetic field induces an electromotive force (EMF) in a conductor.
Lorentz Force Law: Describes the force on a charged particle moving through an electric and magnetic field.
HIGHLIGHTING WAYS OF DEMAGNETIZING A BAR MAGNET:
HEATING: Heating a magnet above its Curie temperature can disrupt its magnetic domains and demagnetize it.
HAMMERING OR MECHANICAL SHOCK: Subjecting a magnet to strong mechanical shock or hammering can disrupt its alignment and demagnetize it.
PASSING ALTERNATING CURRENT (AC) THROUGH IT: Alternating current can induce eddy currents in the magnet, which can disrupt its magnetic domains and demagnetize it.
USING A DEMAGNETIZING COIL: Passing the magnet through a demagnetizing coil that produces a reversing magnetic field can demagnetize it.
