Read the Headline Story to the students. To get students started, suggest that they think about how many gallons of milk a cow produces in a day, a week, or a year, or how much water it drinks in the same amount of time.
Milk cows in the United States produce an average of 26 quarts of milk per day. To produce that amount of milk, a cow drinks almost 33 gallons of water! It takes 1 gallon of milk to make 1 pound of cheese. What can you conclude from these facts?