A soldering iron is a small tool designed to be held in the hand. It has an insulated handle leading to a mains power cable on one end and a thick metal rod with a small tip at the other end. The metal end heats up and is used to melt solder to make joins in electrical and electronics work. This process is known as soldering.
When using a soldering iron, take care to remain aware of it when you place it down between uses, as it remains hot and can burn you if you absentmindedly bump into it. The insulated handle always has a flared lip where the metal starts and usually tapers smaller towards the back too, so that when the soldering iron is placed down on a flat surface, it easily sits on just the handle with the metal tip up in the air to save the work bench from burns. Alternatively, you can use a soldering iron stand, which looks like a big open spring mounted at an angle on a base. The metal rod part of the soldering iron is then placed down into the middle of the spring between uses.
Soldering irons used for general eletronics tend to range between 16 to 40 Watts. Higher wattage soldering irons do exist, but may not be appropriate for the average hobbyist. Soldering irons are commonly plugged into a mains power point, however there are models that run on batteries or gas instead. Battery operated soldering irons have a lower wattage and therefore have more limited use. Gas powered soldering irons usually run on butane and can be quite powerful, however they usually do not have a feedback control system to make the tip follow a set temperature, plus you have to top up the gas tank occasionally. A mains power soldering iron is usually more desired unless portability in the field or heatshrinking is specifically required.
Many models have interchangeable tips, which come in a variety for different types of soldering work. Conical, pyramid, flat, chisel, knife, concave, or wicking tips for soldering, curved or straight. Blower tip for blowing gas powered hot air to use on heatshrink tubing. Soldering tips have a copper core for heat transfer that is plated with iron for durability or thinly coated in nickel. If the tip becomes damaged through filing, over zealous abrasive cleaning, or abuse, the copper may become exposed to the air, which will cause rapid corrosion of the tip. It is best to replace the soldering tip if it has become damaged.