As water boils it is heated to a temperature of 212 degrees Fahrenheit or 100 degree Celsius. The water turns into a gas called steam, which is invisible. A great deal of heat is needed to change water into steam, even when it is already at its boiling point. Under pressure, such as a pressure cooker, steam can get much hotter before it starts to boil. After an ice cube melts, one is left with water. The water left will slowly begin to disappear into the atmosphere and become a gas.