Basic Magnetic Properties Magnets are fun to play with.

Magnets and electric charges Magnets have 2 poles (North and South) There exist 2 different electric charges (positive and negative) Electric charges and poles are not the same thing!!!

Some things which charges (electric) and poles (magnetic) have in common Opposites attract and “like” repel A force exists between 2 charges or 2 poles Force decreases with distance Forces exist and are invisible (act through a vacuum)

Magnetic materials Certain materials are “magnetic” or can retain magnetic properties. These include iron, nickel, and cobalt. Magnetic materials were originally found in the ground. Today magnets are “made” by placing materials in a strong magnetic field

The Poles Magnets have a North and South pole The Poles exist together in pairs, can’t separate a North from a South Magnetic field lines leave the North and enter the South A magnet aligns itself with the magnetic field lines

Magnetic field lines Field lines leave the North and enter the south A compass (which is a magnet) aligns itself with the North pointing in the direction of the magnetic field lines

Making Magnets Magnets are made by placing magnetic materials in a strong magnetic field In these materials the little magnetic dipoles all line up, creating a North at one end and a South at the other.

Why does magnetism exist? Magnetism exists because moving charges create magnetic fields. These moving charges create little baby magnets inside the material. When all these little baby magnets line up, they create one big magnet

Break a magnet in half? Breaking a magnet in half just creates two smaller magnets

Earth’s magnetic field The earth has a magnetic field. A compass aligns itself with this field, with the North side of the compass point towards the magnetic South. We call the North pole the North pole because the North on the compass points in this direction. The “North Pole” is actually magnetically South There is evidence that every few gazillion years the poles reverse. The magnetic fields are important for our survival as they deflect charged particles flying at us from the sun.

Earth’s magnetic field