ABSTRACT
Temperature is a measure of molecular vibration. Some commonly known temperatures are shown for these three units: lowest possible temperature, absolute zero, freezing point of water, human body, boiling point of water, and approximate melting point of steel. A few different methods and measuring principles are commonly used to measure temperature. When a liquid is heated other properties like viscosity and density will also change in proportional to the temperature change. A platinum resistance thermometer (PRT) is the most common example where the electrical resistance of the metal is used to measure temperature. A thermocouple is a temperature sensor consisting of two wires made of different materials. An infrared pyrometer can collect the radiated energy and recalculate this to temperature. Thermal conductivity in general plays an important role for temperature measurement, not only inside the sensor but also outside the sensor.
