Effect of temperature on magnets
Increasing the temperature of a magnet reduces its strength.
A magnet is an object that will produce a magnetic field around it. The magnetic field will attract ferrous materials like iron or nickel. It also attracts or repels other magnets depending, on the polarity of the other magnets.
Permanent magnets are made from materials that will remain magnetized and are hence able to maintain the magnetic field around them continuously. An example is the small magnets used to hold notes on refrigerator doors. Ferromagnetic materials like iron, cobalt and nickel have a very strong attraction towards magnets. Some ferromagnetic materials will become magnetic when exposed to a magnetic field for a long time. They will be able to retain the magnetic properties even after the field is removed. Other "soft" ferromagnetic materials will lose their magnetism once the magnetic field disappears.
When an electric current flows through a coiled wire, an electromagnet will be produced. However, when the current is removed, the magnetic properties will be lost. By placing ferromagnetic materials in the middle of the coil, the magnetic strength of the coil will be increased many times over.
Basic safety requirements. Handle the hot plate with care - adult supervision required