This education activity about the water footprint of food helps students see beyond tap water use and understand the large amounts of water involved in food production.
This Education Activity was created to help students understand the large water footprint of food and agriculture. It is adapted from “Lesson 2: My Water Footprint” (pp. 5-7), one of the three comprehensive plans in Lessons for Understanding Our Water Footprint, designed both High School and Middle School students.
Because agriculture and food production consume the most water worldwide, it’s important for students to understand the influences on their dietary choices and how those choices affect them, their community and the communities where food is produced. Educators can use this activity to demonstrate how different foods require different amounts of water based on rainfall versus irrigation, climate, soil, biology, production techniques, processing and so forth. The Water Footprint of Food Guide supports and extends this activity by allowing teachers and students to choose from many more foods and beverages.
Activity Materials List
Pasta sauce jar (24 oz/680 g) or download and print out (illustration)
Chocolate bar (1.55 oz/43 g) or download and print out (illustration)
Steak (6 oz/170 g) or download and print out (illustration)
Gallon jug or download and print out (illustration)
Liter bottle or download and print out (illustration)
In addition to the three foods listed, you can select various foods to showcase with the help of the Water Footprint of Food Guide, which provides the water footprint and other information for more than 100 foods and beverages. Note that the water footprint values below may differ from those found in the lesson plan due to data updates since publication.
This lesson can be stretched into two or more class periods. For instance, educators can also assign students the Elaborate activity to consider at home, and then begin the next class period with the Evaluate activity.
1. Hold up a 24 oz/680 g jar of pasta sauce or display an illustration, such as this one: Download Pasta Sauce Jar Illustration
2. There may be a little bit of water in this sauce, but not much, right? To make the pasta sauce, though, water is needed to grow the tomatoes, sugar, garlic, and onions. So how much water, including this “virtual” water, do you think was needed to make this pasta sauce? Hold a liter-sized container of water next to the jar of sauce and say: Imagine 254 of these—this is how many liters of water are needed to produce this one jar of sauce. (If using the standard US system of measurement, hold up a gallon-sized container of water and say: 67 of these are needed to create this much sauce.)
3. Next, hold up a typical 1.55 oz/43 g chocolate bar or display an illustration, such as this one: Download Chocolate Bar Illustration
4. Ask: How much water, including any “virtual” water, do you think is required to make this one candy bar? Hold the gallon-sized container of water next to the candy bar and say: The equivalent of 200 of these is needed to make this one little candy bar. (If using the metric system, hold up a gallon-sized jar and say: 757 of these are needed to make this one bar.)
5. Finally, hold up a 6 oz/170 g steak or display an illustration, such as this one: Download Steak Illustration
Ask: How many gallons (liters) of water do you think it took to produce a steak this size? Hold up the gallon (or liter) container of water again and explain that about 695 gallons (2,628 liters) of water are needed to produce just one small steak. Ask students to imagine pouring all that water into this room. How much of the classroom would 695 gallons (2,628 liters) of water occupy?
7. At this point, remind students to think back to the water footprint they calculated from WaterCalculator.org in the last lesson. They may recall that it is not their household’s indoor or outdoor water use, but rather their virtual water use—and particularly their diet—that makes up most of their water footprint.
8. Explain that, for most people, diet is the biggest consumer of virtual water. In fact, in a typical person’s water footprint, about two-thirds of the water comes from virtual water needed to produce their food. So investing a little time into understanding why our diet has such a large water footprint is the mission of this lesson.
9. Divide the class into four groups.
10. Give each group one of the Food’s Water Footprint Research Cards. Instruct each group’s members to work together to conduct research on the topic on their card. These topics are explored on the Watercalculator.org site, so the web address on the back of their card is a good place for them to start.
11. Tell the groups that the goal is for them to consolidate what they learn into a mini-lesson that they can teach to their classmates. Tell them that, rather than simply reading what they find on the website, you expect them to organize graphics, videos, and other information related to the topic into a cohesive lesson that they can use to make the topic interesting and engaging to their classmates. Give each group a copy of the Food’s Water Footprint Mini-Lesson Team Rubric to set expectations and help guide their progress.
12. As students begin their work, touch base with each group to ensure they have an effective strategy for approaching the assignment. Make sure they have reviewed the rubric and set expectations for their group, including how much time to allot for researching, lesson planning, writing the lesson, and presenting, as well as roles for each team member, etc.
13. Have each group share their mini-lesson with the class. If time permits, include a question-and-answer session after each presentation.
14. Have students take out a piece of paper and a writing instrument. Tell them they will have two minutes to respond to a writing prompt. The idea is to not think too much about it, but simply to record ideas that come to them. Then share the writing prompt: What are some ways that your diet is influenced by social groups, advertising, and structures at home and at school that encourage a large water footprint for food?
15. After two minutes, tell students you are now going to give them another two minutes to brainstorm ways they might influence those structures to reduce their water footprint.
16. Facilitate a full-class discussion for students to share their thoughts and ideas. Begin by asking students to share some of the influences they recorded. Write those on the board. Have students share their ideas on how they might influence those structures to reduce their water footprint, and then have them share feedback on those ideas. Encourage them to keep their input constructive by using “I wonder if …” or “What if …?” statements rather than blurting out feedback.