Worksheet Grade 8 Science

Dry Hollow Orchard: Water Use for Three Irrigation Methods

A grade 8 science worksheet comparing flood, sprinkler, and drip irrigation at a fictional orchard using scientific notation, savings, and acre-foot conversions.

Grade: Grade 8
Subject: Science
Material: Worksheet
Time: 40 min
Prep: No prep
Materials: Calculator

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: Items 3, 7, and 8 build an evidence-based argument for how per-capita and agricultural water consumption strains a shared aquifer as more acres are irrigated.

All materials for MS-ESS3-4 →

8.EE.A.3 Common Core Math

Use numbers expressed in the form of a single digit times an integer power of 10 to estimate very large or very small quantities, and to express how many times as much one is than the other.

How this material aligns: Items 1, 2, 5, and 10 write multimillion-gallon seasonal totals in scientific notation and compare how many times more water one method uses than another.

All materials for 8.EE.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 calculate and compare seasonal water use for three irrigation methods using scientific notation.
Students will argue how a method choice affects the amount of water withdrawn from a shared aquifer.

Vocabulary

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.
Acre-foot: The amount of water it takes to cover one acre of land, about the size of a football field, one foot deep. Western states use acre-feet to measure large amounts of water.

Also: irrigation, scientific notation

Teacher overview

Fictional Dry Hollow Orchard grows 40 acres of apple trees and draws its irrigation water from a local aquifer. The grower is comparing three ways to water the trees, flood, sprinkler, and drip, each of which delivers a different amount of water per acre over a season. This worksheet has students compute the seasonal totals in scientific notation, find the water saved by switching methods, and argue how the choice affects the aquifer that many farms share.

Dry Hollow Orchard: Water Use for Three Irrigation Methods — Grade 8 Science

Name: ____________________________ Date: ______________

Student Worksheet

Suppose the fictional Dry Hollow Orchard covers 40 acres. Over one growing season, each irrigation method delivers a set amount of water per acre:

Flood irrigation: 900,000 gallons per acre
Sprinkler irrigation: 600,000 gallons per acre
Drip irrigation: 400,000 gallons per acre

Use 1 acre-foot = 325,851 gallons where a conversion is needed.

Find the total water the orchard would use in one season with flood irrigation, then write that total in scientific notation.
Find the total for drip irrigation and write it in scientific notation.
How much water would the orchard save in one season by switching from flood to drip? Write the savings in scientific notation.
Per acre, how many times as much water does flood irrigation use as drip irrigation?
Find the sprinkler total for the whole orchard and write it in scientific notation.
Convert the drip-irrigation seasonal total from question 2 into acre-feet, to the nearest whole acre-foot.
What percent less water does drip use than flood over the season? Round to the nearest tenth of a percent.
As more orchards near Dry Hollow expand, explain how the method each grower chooses affects the shared aquifer.
Explain why drip irrigation uses less water than flood irrigation to grow the same trees.
Estimate the flood total from question 1 as a single digit times a power of ten.

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: 3.6 × 10^7 gallons. 900,000 × 40 = 36,000,000 gallons, which is 3.6 × 10^7 gallons.
Answer: 1.6 × 10^7 gallons. 400,000 × 40 = 16,000,000 gallons, which is 1.6 × 10^7 gallons.
Answer: 2.0 × 10^7 gallons. 36,000,000 − 16,000,000 = 20,000,000 gallons, which is 2.0 × 10^7 gallons.
Answer: 2.25 times. 900,000 ÷ 400,000 = 2.25, so flood uses 2.25 times as much water per acre.
Answer: 2.4 × 10^7 gallons. 600,000 × 40 = 24,000,000 gallons, which is 2.4 × 10^7 gallons.
Answer: 49 acre-feet. 16,000,000 ÷ 325,851 = 49.1, which rounds to 49 acre-feet.
Answer: 55.6 percent. (36,000,000 − 16,000,000) ÷ 36,000,000 × 100 = 20 ÷ 36 × 100 ≈ 55.6%.
Answer: Each grower who chooses drip instead of flood withdraws far less water, so as more orchards expand, method choice decides whether total pumping stays within what the aquifer can recharge or draws it down faster than it refills.
Answer: Drip irrigation drips water slowly right at the roots, so less is lost to evaporation and runoff than with flood irrigation, which spreads water across the whole field where much of it never reaches the trees.
Answer: 4 × 10^7 gallons. The flood total of 36,000,000 gallons rounds to about 4 × 10^7 gallons for a quick estimate.

Differentiation

Support

Provide a partly finished table with the per-acre amounts and the 40-acre multiplier already labeled, so students focus on the multiplication and the scientific-notation step. Offer a worked example converting a different total to acre-feet before item 6.

Extension

Ask students to design a fourth method that would use a seasonal total between the sprinkler and drip results, state its gallons per acre, and show the calculation that proves the total falls in that range.

ELL supports

Pre-teach "irrigation," "per acre," "savings," and "acre-foot" with simple pictures of a flooded field, a sprinkler, and a drip line. Allow students to record answers as numbers plus a labeled sketch rather than full sentences for items 8 and 9.