An inflatable pool float may seem quite firm as it sits on a deck in the hot sun. However, minutes after you toss to float into the cold pool, the same float may seem under-inflated. You may suspect that the float has developed a slow leak, but that may not be the most likely explanation for the apparent loss of air pressure. It may be that Charles's law is responsible. Charles's law, discovered by Jacques Charles, states that the volume of a quantity of gas, held at constant pressure, varies directly with the Kelvin temperature.
Gases expand as they are heated and they contract when they are cooled.
In other words, as the temperature of a sample of gas at constant pressure increases, the volume increases. As the temperature goes down, the volume decreases as well. First change the Celsius temperature to Kelvin. Now list the given quantities and the unknown. Now predict the results.