Lesson Q4 L1 – The Water Cycle in the Garden and the Watershed
Lesson Overview
Quarter 4 · Unit 4A: Water in the Desert · Week 28 · Grades 6–8 · Lesson length: 50 minutes
Essential Question: How does water move through the garden, the desert, and the atmosphere, and what drives it?
Lesson Focus: Teams build sealed “garden in a bag” water cycle models with soil and a seedling, observe evaporation, transpiration, condensation, and precipitation over the lesson, then trace water from a monsoon storm through the Salt River watershed to our garden hose.
Why It Matters: The water cycle is driven by the Sun’s energy and gravity (MS-ESS2-4) and cycles matter through the hydrosphere, atmosphere, and geosphere (7.E1U1.5). It frames Quarter 4’s focus on water in the desert.
Source: New lesson written for this series (2026).
Standards & Learning Targets
Standards Alignment
NGSS Middle School Performance Expectations: MS-ESS2-4 — Develop a model to describe the cycling of water through Earth's systems driven by energy from the sun and the force of gravity
Science & Engineering Practices / Crosscutting Concepts: Developing and Using Models; Energy and Matter (CCC); Systems and System Models (CCC)
Student Learning Targets
Learning Targets — students will be able to
Describe evaporation, transpiration, condensation, precipitation, infiltration, runoff, and groundwater flow
Build and observe a model showing water moving through a plant and soil system
Explain how the Sun’s energy and gravity drive the water cycle
Key Vocabulary
water cycle · evaporation · transpiration · condensation · precipitation · runoff · groundwater · watershed
Materials & Teacher Prep
| Materials Needed | Teacher Prep Checklist |
|---|---|
|
|
Low-Cost Option: No zip bags? Use clear plastic cups with a second cup taped on top. Any seedling or a weed works.
Safety: Bag models go on a sunny window or under an LED lamp; keep water away from cords and outlets and do not touch hot bulbs. See Appendix I.
Equipment Procedure — Sealed water cycle model
- Add 3 cm of moist soil to the bag and plant one seedling.
- Place a small cup with 20 mL of water in one corner (the “lake”).
- Seal the bag with some air inside and tape it to a sunny window or place it 20 cm under a lamp.
- Observe every 10 minutes for droplets on the plastic (condensation) and drips (precipitation).
- Record observations, label the processes on a sketch, and keep the model for a week of observations.
Lesson Flow & Timing
| Engage · 5 min | Explore · 20 min | Explain · 10 min | Elaborate · 10 min | Evaluate · 5 min |
|---|---|---|---|---|
| Where was this water last week? | Bag models and watershed trace (RoundTable) | The water cycle and its drivers | Labeled model | Exit ticket |
Phase 1 · Engage — The Hook
Teacher Talk
Start local: our school garden is one small part of the Salt River watershed.
PCM: Curiosity. Fill a glass from the tap. “This water may have fallen as snow on the White Mountains last winter, flowed down the Salt River, sat in Roosevelt Lake, and traveled through a canal to our school. Let’s trace its trip, and its trip back to the sky.”
Ask Students
“Where does Phoenix’s water come from?” “Where does water go after we water the garden?” “What makes water rise into the air?”
PCM Differentiation
Thinker Students: A radish plant can transpire many times its own mass in water over its life. Where does that water go, and what energy moves it?
Harmonizer Students: Everyone downstream shares the same rivers. How should communities upstream and downstream treat water?
Phase 2 · Explore — Kagan Cooperative Activity
Cooperative Structure
Kagan structure: RoundTable. Teammates take turns adding one process label and arrow to a shared watershed diagram, passing the paper around until the cycle is complete (See the Teaching Reference for the structure’s steps.) Have students jot evaporation (liquid water becomes water vapor using energy from the Sun), transpiration (water evaporates from plant leaves through stomata), condensation (water vapor cools and becomes droplets (clouds, dew)), runoff, and watershed (the land area that drains into a river) at the top of their notes; Explain will define them precisely.
Step-by-Step
- Step 1 — Build (7 min): Teams build two bag models following the equipment procedure and place them in sun or under a lamp.
- Step 2 — Watershed trace (7 min): In turn, each teammate adds one step on the shared diagram: snow, melt, river, reservoir, canal, garden, infiltration, transpiration, evaporation, clouds.
- Step 3 — Observe (4 min): Teams check the bags for condensation and record.
- Step 4 — Label (2 min): Teams label the bag sketch with each process seen.
Teacher Moves During Explore
Ask, “Where did the water on the bag come from: the soil, the cup, or the plant?”
Ask, “What energy source is driving the model?”
Point out gravity’s role in drips, runoff, and rivers
Phase 3 · Explain — Direct Instruction
Mini-lesson — The water cycle and its drivers. Teacher move: Draw the cycle over a desert landscape: Sun drives evaporation and transpiration; condensation forms clouds; gravity pulls precipitation down, makes runoff flow downhill, and moves groundwater.
Evaporation: liquid water becomes water vapor using energy from the Sun
Transpiration: water evaporates from plant leaves through stomata
Condensation and precipitation: water vapor cools and becomes droplets (clouds, dew); droplets fall as rain or snow
Infiltration, runoff, and groundwater: gravity moves water into soil, across surfaces, and slowly through aquifers
Watershed: the land area that drains into a river; Phoenix depends on the Salt and Verde watersheds, the Colorado River (through the CAP canal), and groundwater
Key Message: Water cycles through the atmosphere, land, living things, and underground, driven by energy from the Sun and the pull of gravity. Our garden is one small part of the Salt River watershed.
Check for Understanding — Ask Students
“What provides the energy for evaporation?” “What role does gravity play in the water cycle?” “Where does Phoenix’s water come from?”
Phase 4 · Elaborate — Student Product & Differentiation
Student Product
Each student draws a labeled water cycle model that includes the garden, a plant, a watershed, and at least seven processes, marking where the Sun and gravity act.
Differentiation
| Grade 6 focus | Grade 7 focus | Grade 8 focus |
|---|---|---|
| Label water cycle processes in the bag model. | Explain how energy from the Sun and gravity drive each process. | Trace water through Phoenix’s watershed and evaluate how human systems (dams, canals, pumping) change the natural cycle. |
Support (scaffolded entry): Provide a water cycle diagram with blanks and a word bank.
Challenge Extension: Use the SRP or USGS website to find the current storage level of Roosevelt Lake and explain what it means for Phoenix water.
Multilingual Learners: Visual cycle with arrows; cognates evaporación, condensación, precipitación, transpiración.
Phase 5 · Evaluate — Closure, Exit Ticket & Assessment
Exit Ticket
- Name four processes you observed or modeled.
- What two forces drive the water cycle?
- Name one source of Phoenix’s water.
Answer Key / Look-Fors: (1) Evaporation, transpiration, condensation, precipitation, infiltration, runoff. (2) Energy from the Sun and gravity. (3) Salt and Verde rivers, Colorado River (CAP), groundwater, reclaimed water.
Grade-Level Practice Items
Grade 6. Which process turns liquid water into water vapor?
A) condensation B) precipitation C) evaporation D) infiltration
Answer: C — Evaporation changes liquid to vapor.
Grade 7. Droplets formed on the inside of the sealed bag. What process is this, and why does it happen?
A) Evaporation; heat is added B) Condensation; water vapor cools on the plastic C) Precipitation; gravity D) Transpiration; roots push water
Answer: B — Vapor cools on the surface and condenses.
Grade 8. Which statement best describes the roles of energy and gravity in the water cycle?
A) Gravity causes evaporation. B) The Sun’s energy drives evaporation and transpiration, and gravity drives precipitation, runoff, and groundwater flow. C) The Moon drives the water cycle. D) Wind alone moves all water.
Answer: B — Solar energy lifts water; gravity brings it down and moves it downhill.
Grade-Level Short Response (for quizzes and tests)
Grade 6. Describe the path of water from a garden bed back to a cloud.
Look-for: Evaporation from soil or transpiration from leaves; vapor rises; condenses into clouds.
Grade 7. Explain how the Sun and gravity each drive parts of the water cycle.
Look-for: Sun: evaporation, transpiration; gravity: precipitation, runoff, infiltration, groundwater.
Grade 8. Explain how dams and canals in the Salt River watershed change the natural movement of water.
Look-for: Store water in reservoirs, move it long distances, increase evaporation from lakes, reduce downstream flow.
Expanding Circles
How does this connect to… Self — Where does your home’s water come from? • Classroom — How much water does our garden use? • School — Where does campus runoff go during a storm? • Community — How does Phoenix get water from rivers far away? • World — How does the water cycle connect every continent?
Formative Assessment
Formative Assessment (sort students by the garden-and-watershed water cycle model, the exit-ticket processes and Phoenix water source, and the grade-level practice items)
Meets (3): Model includes seven processes, the garden, a plant, a watershed, and correct Sun and gravity labels.
Approaching (2): Model missing processes or drivers.
Not Yet (1): Confuses processes; reteach with the bag model observation.
Extend & Looking Ahead
Video recap: play the 1-minute video for your grade — Grade 6; Grade 7; Grade 8.
Extension: Keep the bag model for a week and record how often condensation and drips occur.
Looking Ahead: In Lesson 4.2 we investigate Arizona’s water supply and how much water people use.