what happens when iron is heated

It gets hot. Ha, Ha. But I'm sure you didn't want that for an answer. Please be more specific about what you are looking for and I can refine that answer for you.

When iron is heated, several physical and chemical changes occur. The specific changes depend on the temperature and duration of heating.

1. Expanding: Like most materials, iron expands when heated. This is due to the increased kinetic energy of the iron atoms, causing them to move more vigorously and occupy a larger volume.

2. Color change: Initially, iron is a silver-gray color. As it is heated to high temperatures (above 700°C or 1292°F), it starts to glow red, then orange, then yellow, and finally white-hot. These color changes result from the emission of light as iron atoms become excited by the heat.

3. Magnetic behavior: Iron possesses strong magnetic properties. When heated to high temperatures (above its Curie point, around 770°C or 1418°F), iron loses its magnetism and becomes paramagnetic, meaning it weakly responds to magnetic fields.

4. Oxidation: Iron readily reacts with oxygen in the presence of heat, leading to the formation of iron oxide or rust. This process is known as oxidation, and it causes the iron to corrode and weaken over time.

5. Melting: Iron has a melting point of around 1538°C or 2800°F. When heated to this temperature (or higher), solid iron undergoes a phase transition and turns into a liquid state. Molten iron can be molded and used in various industrial processes.

It's important to note that the specific effects of heating iron can vary depending on the purity of the iron, its composition (e.g., alloyed with carbon or other elements), and the conditions under which it is heated.