Sal continues this short series on specific heat and vaporization. The situation he poses uses 500 grams of liquid water at 60 degrees Celsius, with the goal of getting the water to 0 degrees Celsius. The ice he adds to the water comes out at -10 degrees Celsius. The question is; how much of this ice is needed to get the sample of water down to 0 degrees Celsius? The rest of the video deals with the calculations necessary to arrive at the answer.