Introduction to Magnetism Goal: I can explain basic magnetic phenomena as it appears in the real-world

Introduction to Magnetism copy Introduction to Magnetism Magnets Naturally occurring magnets are known as Iodestone Magnetic Fields Similar to electric fields Force of attraction/repulsion caused by dipoles Two defining characteristics: Magnetic fields occur naturally in substances that have magnetic character (internal make-up) Can effect not only other magnetic substances, but also electric charges

copy Magnetic Character Related to the condition of the atoms in the material Not fully understood Domain Theory All large magnets are made up of many magnetic regions called domains The magnetic character of domains comes from the presence of even smaller units called dipoles Dipoles are called North and South Dipoles interact with their neighbouring dipoles If they align with all of the poles in one direction, then a larger magnetic domain is produced

Example: a diagram of domain theory copy Example: a diagram of domain theory Materials that allow for the dipoles to be aligned to create a greater magnetic character are known as ferromagnetic materials (i.e. nickel, iron, cobalt)

copy Law of Magnetic Forces Similar magnetic poles repel each other with a force Dissimilar magnetic poles attract each other

Magnetic Phenomena Magnetic Induction copy Magnetic Phenomena Magnetic Induction Ferromagnetic materials can be magnetized Permanent and Temporary Magnetism Some materials demagnetize easily, others maintain their magnetic domains Reverse Magnetism A magnet can have its polarity reversed Breaking a Large Magnet Can create smaller active magnets Maximum Strength There is a limit to how strong a magnet can be

Sketching Magnetic Fields copy Sketching Magnetic Fields The number of field lines drawn are proportional to the strength of the field The direction of the field is defined by the direction the north pole of the test magnet would point