15. How do you make a thermocouple?
Thermocouples are devices that are used to measure temperature. A thermocouple is a set of two wires welded together at one end, where a junction is formed between the two wires. Because each wire is composed of a different type of metal, each wire reacts differently to the temperature of the junction. Because of this difference, a voltage is generated. The voltage varies consistently with changes in temperature, and so there are devices, such as digital thermometers, that measure the voltage and convert it to a temperature reading.