Magnets

• Some materials can be made into permanent magnets.
• Although a magnetized piece of iron is called a “permanent” magnet, its magnetism can be weakened or even removed.
• Iron is a soft magnetic material.
• It is easily magnetized, it tends to lose its magnetic properties easily.
• Cobalt is a hard magnetic material.
• It more difficult to magnetize, once magnetized, it doesn’t lose its magnetism easily
• Magnets exert magnetic forces on each other.
• Like poles repel, and opposite poles attract.
• A magnetic pole is one of two points, such as the ends of a magnet, that have opposing magnetic qualities.
• Magnets have a pair of poles, a north pole and a south pole.
• It is impossible to isolate a south magnetic pole from a north magnetic pole.
• Magnets are sources of magnetic fields.
• Magnetic force is a field force.
• When magnets repel or attract each other, it is due to the interaction of their magnetic fields.
• A magnetic field is a region where a magnetic force can be detected.
• Magnetic field lines are used to represent a magnetic field.
• The magnetic field gets weaker with distance from the magnet.
• Compasses can track magnetic fields.
• A compass is a magnet suspended on top of a pivot so that the magnet can rotate freely.
• A compass aligns with Earth’s magnetic field.
• Earth’s magnetic field is like that of a bar magnet.
• Earth’s magnetic field has changed direction throughout geologic time.
• Earth’s magnetic poles are not the same as its geographic poles