Why are wires joined together with solder?

Wires are joined together with solder primarily to ensure minimum resistance in the electrical connection. Solder is a conductive material, typically made from a metal alloy, which has excellent electrical properties. When wires are soldered, the solder fills any gaps or spaces between the metal surfaces of the wires being joined. This creates a solid, low-resistance path for electrical current to flow through, reducing energy loss and ensuring efficient operation in electrical circuits.

Opting for minimum resistance is crucial in electrical connections as high resistance can lead to excessive heating, energy loss, and potential failure of the circuit. In contrast, the focus on maximum resistance, insulating purposes, or improving airflow does not align with the fundamental purpose of soldering wires. Maximum resistance would be counterproductive in most electrical applications, while insulating purposes are typically served by materials other than solder. Similarly, improving airflow is irrelevant to the purpose of soldering, which centers around creating reliable and efficient electrical connections.