Lesson plan Grade 6 Science

Redfern Farm's Water Footprint: Comparing Foods and Irrigation

A 50-minute grade 6 science lesson where students use water-footprint figures and a fictional farm's irrigation switch to argue how food choices affect water supply.

Grade: Grade 6
Subject: Science
Material: Lesson plan
Time: 50 min
Prep: Low prep
Materials: Printed student handout, Two plates or photos showing a beef dish and a bread roll, Exit cards

Standards

MS-ESS3-4 NGSS

Construct an argument supported by evidence for how increases in human population and per-capita consumption of natural resources impact Earth's systems.

How this material aligns: In the closing task students argue from water-footprint evidence how growing more low-water food affects supply as population rises, matching this standard's argument about consumption impacts.

All materials for MS-ESS3-4 →

6.RP.A.3 Common Core Math

Use ratio and rate reasoning to solve real-world and mathematical problems, e.g., by reasoning about tables of equivalent ratios, tape diagrams, double number line diagrams, or equations, including finding a percent of a quantity and converting measurement units.

How this material aligns: The worked example and handout items 1 through 5 use unit rates and a percent, such as 220 gallons per pound and 25 percent saved, the ratio reasoning this standard targets.

All materials for 6.RP.A.3 →

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This material is in the public domain (CC0) and may be copied, edited, and shared freely, without attribution. Updated 2026-07-23.

Objectives

Students will use water-footprint rates to calculate the water needed to produce given amounts of food.
Students will argue from evidence how shifting food and irrigation choices affects a region's water supply.

Vocabulary

Water footprint: All the water it takes to make the things we use and eat, counting water used far away. A hamburger's water footprint includes the water that grew the cattle's feed.
Drip irrigation: Watering plants through tubes that release water slowly, drop by drop, right at the roots. Very little water is wasted along the way.

Also: irrigation, consumption

Teacher overview

Most of the water people use never comes out of a home faucet; it is used to grow food. Agriculture accounts for roughly 70 percent of the fresh water people withdraw worldwide, and different foods take very different amounts. This lesson uses commonly cited water-footprint figures and Redfern Farm, a fictional farm, to give students a concrete argument-from-evidence task about how food and irrigation choices shape water supply. A common student misconception is that all foods take about the same amount of water to grow; the numbers in this lesson correct that directly, since a pound of beef takes far more than a pound of wheat.

Procedure

Hook (5 min): Show two plates or photos, one with a beef dish and one with a bread roll (for display only, not for eating), and ask students to guess which took more water to produce and by how much. Record guesses on the board without comment.

Direct instruction and worked example (12 min): Introduce the water footprint as the total water used to produce a food. Give the commonly cited figures: about 1,800 gallons for a pound of beef and about 220 gallons for a pound of wheat. Point out that most of the beef figure is rainwater used by the pasture and feed crops cattle eat, not irrigation or tap water. Model the worked example on the board: 3 pounds of wheat takes 3 times 220 = 660 gallons. Then show the ratio of beef to wheat, 1,800 to 220, which reduces to 90 to 11, meaning a pound of beef takes about 8 times the water of a pound of wheat.

Guided practice (12 min): With the class, work handout items 1 and 2 together, checking that students multiply the pounds by the correct rate. Then introduce Redfern Farm's irrigation change: the farm moves 10 acres from flood irrigation to drip irrigation and cuts water on those acres from 40,000 to 30,000 gallons a day. Ask students to find the daily savings before they work the rest of the handout.

Independent practice (13 min): Students complete handout items 3 through 6 on their own, showing each calculation. Circulate and check that percent in item 5 is found by dividing the change by the starting amount.

Closure and exit ticket (8 min): Students write a short claim-and-evidence response to item 6 on an exit card: how could growing more of a low-water food instead of a high-water food help a region's water supply as its population grows? Collect and scan for a clear claim supported by at least one number from the lesson.

Redfern Farm's Water Footprint: Comparing Foods and Irrigation — Grade 6 Science

Name: ____________________________ Date: ______________

Student Handout

Use these figures for every item. Redfern Farm is a fictional farm.

A pound of beef takes about 1,800 gallons of water to produce.
A pound of wheat takes about 220 gallons of water to produce.
Agriculture uses about 70 percent of the fresh water people take from rivers, lakes, and wells.

How much water does it take to produce 5 pounds of wheat?
How much water does it take to produce 2 pounds of beef?
Write the ratio of water for 1 pound of beef to water for 1 pound of wheat, then reduce it.
Redfern Farm moves 10 acres to drip irrigation and cuts water on those acres from 40,000 to 30,000 gallons a day. How many gallons does the farm save each day?
What percent of the old 40,000-gallon daily amount does that saving represent?
Agriculture uses about 70 percent of the fresh water people take from rivers, lakes, and wells. Make a claim: how could growing more low-water food instead of high-water food affect a region's water supply as its population grows? Support your claim with at least one number from this lesson.

From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.

Answer Key

Answer: 1,100 gallons.
5 pounds times 220 gallons per pound = 1,100 gallons.
Answer: 3,600 gallons.
2 pounds times 1,800 gallons per pound = 3,600 gallons.
Answer: 90 to 11.
1,800 to 220 reduces by dividing both by 20, giving 90 to 11, which is about 8 to 1.
Answer: 10,000 gallons per day.
40,000 minus 30,000 = 10,000 gallons saved each day.
Answer: 25 percent.
10,000 divided by 40,000 = 0.25, which is 25 percent.
Answer: Accept any clear claim supported by a lesson figure, such as: growing more wheat-type foods instead of beef could stretch a region's water further, because a pound of beef takes about 1,800 gallons while a pound of wheat takes about 220, so the same water grows far more low-water food as the population and its food needs rise. Stronger answers may note that most of the beef figure is rainwater used by pasture and feed crops, so the savings in river, lake, and well water would be smaller than the full difference.

Differentiation

Support

Give students the rates already labeled with their units and a filled-in example (4 pounds of wheat worked through) before independent practice. Provide the subtraction for item 4 already set up as "40,000 minus 30,000" so students focus on the meaning of the savings.

Extension

Ask students to find how much water the farm saves in a 30-day month from the daily savings in item 4, then write two sentences on whether that monthly figure changes how strong they think the argument in item 6 is.

ELL supports

Pre-teach water footprint, irrigation, and drip irrigation with simple pictures (a cow, a wheat stalk, a drip line). Provide the claim frame "Growing more ___ could help because ___ gallons," and allow students to give the closure response orally.

Extensions

Give students a teacher-provided water-footprint figure for one more food, have them add it to the beef-and-wheat comparison, and rank the three foods from most to least water per pound. Discuss as a class how a school cafeteria might use such a ranking when planning menus, without arguing that any one food is right or wrong to eat.