Story Idea—Bottled Water

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Thirst Quencher Exercise
Drink Preferences: Bottled or Tap Water, Soda, Milk…
(From Professor Melvin Mencher)

Here’s a story idea that combines interviewing about a social trend and personal preferences with (gasp!) mathematics.

What do people drink when they’re thirsty or want a drink to go along with a meal?

The Drinking Data
The first two columns below compare average annual consumption in gallons of 10 years ago with current consumption. The third column lists the percentage change in the decade. You could ask your students to derive the percentages. The figures are from the Beverage Digest (2008). (Note: Blogspot doesn't do tabs, so these numbers are crammed together, separated by slashes.)

Today/ 10 Years Ago/ Percentage Change
Soft drinks: 51/55/-7.3%
Water: 48/42/+14.3%
• Tap water: 27/31/-12.9%
• Bottled water: 21/11/+90.9%
Beer: 22/24/-8.3%
Milk: 20/22/-9.1%
Coffee: 16/20/-11.1%
Juices: 8/9/-20%
Sports drinks: 5/2/+150%
Others: 10/9/+66.7%

Summary
The bottled water industry says its latest figures show bottled water is on equal footing with tap water, 27 gallons a year. If you want to substitute 27 for the 21 figure above, the percentage change would then be +145 percent.

For the story, the significant increase is in bottled water. Although it is 2,800 times more expensive than tap water—$1,400 a year compared with 50 cents for tap water—the cost deters few. Only lately have bottled-water users seemed concerned about the effect on the environment of millions of discarded water bottles. Only 25 percent of them are recycled. Manufacturing the plastic bottles consumes 1.5 million barrels of petroleum a year.

Another glaringly obvious change in these data is the 150% increase in sports drinks—GatorAde and all the rest. Why? What’s in those things? And what about all those plastic bottles?

Assignment
Ask those who prefer bottled water why they buy it when, studies show, it is not as carefully monitored as local tap water. Some tap water is so pure—Boston, New York, San Francisco, Seattle, Portland, Ore.—it isn’t filtered. Forty percent of all bottled water is filtered tap water.
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