Presentation on theme: "Electricity and Magnetism: Magnetic Fields Mr D. Patterson."— Presentation transcript:
Electricity and Magnetism: Magnetic Fields Mr D. Patterson
Outcomes explain the attraction and repulsion effects for magnets, the behaviour of freely suspended magnets and magnetic compasses, and describe the nature of the Earth's magnetic field describe, using diagrams, the magnetic field in various magnetic configurations
This train levitates above the track using magnets
Properties of Magnetism Non contact force North and south poles (dipoles) Like poles repel while unlike poles attract
Magnetic Fields A magnetic field shows the direction the north pole of a small bar magnet will point. Draw field lines away from north poles and toward south poles. Never cross the lines.
The Earth is a Bar Magnet A magnet, in the absence of any other forces will align itself with the magnetic field lines. This is the basis for the compass.
Magnetic flux density (B) is a vector quantity measuring the strength and direction of a magnetic field It is indicated visually by the closeness of the field lines and measured using units of Teslas (T) Magnetic flux Density Larger magnetic flux density Smaller magnetic flux density
Ferromagnetic materials Magnetic effects are created because of: – The motion of charged particles like electrons – A property of electrons called “spin”. Electrons can either be in a state of spin up or spin down.
Ferromagnetic materials Ferromagnetic materials such as iron, nickel, cobalt and some rare earth metals will become permanent magnets when all their magnetic domains line up