Thermodynamic temperature straightforward; for instance, calculating how a temperature change affects the pressure inside an automobile tire. If the tire has a cold pressure of 200 kPa-gage , then in absolute terms (relative to a vacuum), its pressure is 300 kPa-absolute. Room temperature ("cold" in tire terms) is 296 K. If the tire temperature is 20 °C hotter (20 kelvins), the solution is calculated as = 6.8% greater thermodynamic temperature "and" absolute pressure; that is, a pressure of 320 kPa-absolute, which is 220 kPa-gage. The thermodynamic temperature is defined by the ideal gas law and its consequences. It can be linked also
Absolute scale measurements of absolute pressure from weather forecasts, most pressures such as tire pressures and water pressures are measured relative to atmospheric pressure using cheaper and simpler pressure gauges. For this reason, the pressure relative to atmospheric pressure is called gauge pressure and measurements given in units like pounds per square inch (abbreviated lbf/in or psi) are often shown as "psig" (the "g" standing for gauge) or "psia" ("a" for absolute). Absolute scales are used when precise values are needed in comparison to a natural, unchanging zero point. Measurements of length, area and volume are inherently absolute, although measurements of distance