Magnets

• Magnets exert forces caused by magnetic fields; the area around a magnet where magnetic forces act is known as the magnetic field.
• The force of a magnetic field decreases with distance; the nearer objects are to the magnet, the stronger the force.
• Fields around a magnet can be depicted using field lines, which show the direction a freely suspended magnet would point.
• Magnets have two poles: a North and South. Similar poles repel each other, and unlike poles attract each other.
• The Earth acts like a huge magnet with its own magnetic field, referred to as the Earth’s geomagnetism.
• The Earth’s magnetic North pole is not exactly at the geographic North pole; this leads to declination, the difference between magnetic North and true North, which navigational systems have to adjust for.
• Materials that are attracted by magnets are called magnetic materials (examples include iron, cobalt and nickel.)
• Some materials can be induced to be magnetic through a process called magnetisation.
• Ferromagnetism is the basic mechanism by which certain materials form permanent magnets; this is attributed to how their unpaired outer electrons align.
• If magnetised strongly enough, a ferromagnetic material can retain its magnetism when the external field is removed– such material is said to be magnetically hard.
• The magnetosphere is a vast, comet-shaped bubble, which has played a crucial role in our planet’s habitability. The solar wind distorts the Earth’s magnetic field into the magnetosphere, uniquely protecting us from most of the damaging particles and radiation which the Sun emits.