Self-contained breathing apparatus pressure changes with ambient temperature. As temperature decreases, the pressure inside the cylinder decreases. The relationship between the temperature and the pressure of a gas is defined by the formula "PV" = "nRT". (See Universal gas constant.) What is particularly important to understand from the formula is that the temperature is in kelvins, not degrees Fahrenheit. Consider the freezing point of water at 32 °F (0 °C, 273.15 K) and compare it to 96 °F (35.6 °C or 308.71 K; normal human body temperature is 37 °C). While 96 is arithmetically three times 32, the difference in temperature from a
Atmospheric temperature of Campinas, state of São Paulo, Brazil, which lies approximately 60 km north of the Capricorn line (latitude of 22 degrees). Average yearly temperature is 22.4 degrees Celsius, ranging from an average minimum of 12.2 degrees to a maximum of 29.9 degrees. The average temperature range is 11.4 degrees. Variability along the year is small (standard deviation of 2.31 for the maximum monthly average and 4.11 for the minimum). It is easy to see in the graph another typical phenomenon of temperature ranges, which is its increase during winter (lower average air temperature). In Campinas, for example, the daily temperature