Magnetism.
A magnet is an object or device that produces a magnetic field.
Magnet attracts objects made of nickel, iron and cobalt.
A magnet has 2 poles, the North Pole and the South Pole.
Opposite poles of two magnets always attract each other.
Like poles of two magnets always repel each other.
The Earth also behaves like a magnet.
South pole of the Earth's magnet is in the geographical North.
North Pole of the Earth's magnet is in the geographical South.
A freely suspended magnet always rests in the North South direction. This is because opposite poles attract each other.