Heat capacity is the quantity of heat required to raise the temperature of an object by one degree.
It is an extensive property, which is proportional to the mass of the object. The relative heat capacity is the heat capacity per unit of mass, measured in joules per kilogram per kelvin. At room temperature, the specific heat capacity of water is 4180 joules per kilogram per kelvin. In other words, the larger the amount of water, the larger the amount of heat lost is required to cool it down to a certain temperature. If the rate of heat lost remains constant, the larger amount of water would therefore require a longer time to cool down.