Answer :
Juan is most likely converting the measured temperature of saltwater from degrees Celsius to kelvins by adding 273 to the measured value, following the conversion formula TK = TC + 273.
Juan measured the temperature of salt water and then added 273 to the measured value. The conversion he is most likely doing is from degrees Celsius to kelvins. This is because the conversion formula from Celsius to Kelvin is TK = TC + 273.15. When measuring in Celsius and converting to Kelvin, as Juan did, the numerical value for the freezing point of water is 0°C which is equal to 273.15 K, and the boiling point of water is 100°C which is equal to 373.15 K. Since Juan added 273 to his Celsius measurement, he is following the approximate conversion method to get the temperature in Kelvin, which suggests he likely measured the temperature in degrees Celsius originally.
