Understanding the Water Cycle: Modeling and Analysis
NGSS Performance Task
Shared by Nimisha · Free to use as a template on AssessmentWiz.
Rubric
Name: Developing and Using Models
Advanced: Student's revised model meets all proficient criteria AND explicitly models a feedback relationship within the water cycle (e.g., annotating that increased evaporation leads to more water vapor available for condensation, creating a self-reinforcing cycle). The model includes a labeled boundary distinguishing the physical model from the real Earth system, with a written notation of at least one component present in Earth's water cycle that the physical model omits (e.g., transpiration, groundwater infiltration, ocean currents). In the Step 6 extension, the student uses the revised model diagram itself — not just written text — to illustrate the predicted effect of a 2°C temperature increase on evaporation rates, adding a new annotated arrow or annotation to the model.
Beginning: Student produces an initial model diagram that shows water moving between locations (e.g., soil to air to lid) but arrows are unlabeled or labeled only with descriptions of what happens ('water goes up') with no reference to a cause. The revised model in Step 4 repeats the same structure as the initial model without incorporating data from the investigation, and no legend distinguishing liquid water, water vapor, and energy is present. The written model revision note is missing or states only 'we added more arrows.'
Dimension: SEP
Developing: Student produces an initial model with labeled arrows that name at least one process (e.g., 'evaporation,' 'condensation') but do not identify what causes those processes. The revised model adds a legend and marks at least one star (*) where data changed their thinking, but the cause annotations on arrows reference only the process name rather than the mechanism (e.g., 'heat causes evaporation' is written but not connected to the specific temperature data collected). The model revision note identifies one change but does not explain why the data justified that change.
Proficient: Student's revised model diagram includes: labeled arrows for evaporation, condensation, precipitation, and runoff/collection; cause annotations on each arrow that reference energy or temperature as the driver (e.g., 'solar energy heats water surface → molecules escape as vapor'); a legend distinguishing liquid water, water vapor, and energy inputs; and at least two star markings with corresponding model revision note sentences that cite specific data values (e.g., 'We changed the evaporation arrow to show heat as the cause because the warm bin produced 3.2 mL vs. 0.8 mL in the cold bin'). The model accurately represents the Earth systems water cycle mechanism supported by their investigation data.
Name: Cause and Effect: Mechanism and Explanation
Advanced: Student's written argument meets all proficient criteria AND addresses the directionality and magnitude of the cause-and-effect relationship using their quantitative data: the student calculates or estimates the ratio of condensation between conditions (e.g., 'the warm condition produced approximately 4× more condensation') and uses this to reason about what a proportional change in Earth's average temperature would mean for evaporation rates. The reasoning also identifies a potential confounding cause (e.g., 'our model did not control for humidity in the room, which could also affect condensation rates') and explains why their controlled variables still support the cause-and-effect conclusion. The Step 6 extension prediction is justified with a mechanistic chain of at least three linked cause-and-effect steps (e.g., 'higher global temperature → greater thermal energy input to ocean surface → higher evaporation rate → more water vapor in atmosphere → increased precipitation potential').
Beginning: Student's written argument (Step 5) and model annotations describe the water cycle as a sequence of events ('water evaporates, then condenses, then falls') without identifying what causes each event to occur. The claim in the argument does not reference energy, temperature, or any driving mechanism. Evidence cited is qualitative only ('the warm bin had more water on the lid') with no numerical values from the data table. The reasoning section restates the claim or describes observations rather than explaining a mechanism.
Dimension: CCC
Developing: Student's written argument identifies energy or temperature as a cause of evaporation in the claim or reasoning, but the mechanism is stated in general terms without connecting it to the specific data collected (e.g., 'heat causes evaporation, which is why the warm bin had more condensation' — correct causal direction but no quantitative support). The reasoning explains one cause-and-effect link (heat → evaporation) but does not explain the second link (cooling/temperature difference → condensation) or how the two links together create a continuous cycle. At least one quantitative data point is cited but not connected to the mechanism in the reasoning.
Proficient: Student's written argument contains a claim that explicitly names energy transfer as the mechanism driving the water cycle. Evidence includes at least two specific quantitative data points (e.g., 'the warm-water bin averaged 3.1 mL of condensation per interval at 42°C, while the cold-water bin averaged 0.7 mL at 12°C'). The reasoning section explains both cause-and-effect links: (1) increased thermal energy causes water molecules to escape the liquid surface as vapor (evaporation), and (2) when vapor contacts the cooler lid surface, it loses energy and returns to liquid (condensation) — and explicitly states that these two linked mechanisms create a continuous cycle. The reasoning connects the physical model results to the real Earth system (e.g., 'In Earth's water cycle, the sun provides the energy that drives evaporation from oceans and lakes').
Name: Earth Systems: Water Cycle as an Earth System Process
Advanced: Student's model and argument meet all proficient criteria AND demonstrate understanding of the water cycle as a system with interacting reservoirs: the student identifies at least three reservoirs (ocean, atmosphere, groundwater, glaciers, or freshwater lakes) and describes how water residence time differs across reservoirs. The argument or Step 6 extension explains that a change in one Earth system component (e.g., increased ocean surface temperature) creates cascading effects in other components (e.g., increased atmospheric water vapor → increased cloud formation → potential changes in precipitation patterns → altered river discharge and groundwater recharge). The student uses their quantitative data to support a scaled prediction about Earth system behavior, acknowledging the limitations of scaling from a small physical model to a planetary system.
Beginning: Student's model and argument treat the water cycle as occurring in a single location or container rather than as a planetary-scale Earth system process. The student identifies only one or two water cycle processes (e.g., evaporation and rain) and does not connect them into a continuous cycle. In the Step 6 extension, the student does not identify any limitation of the physical model relative to the real Earth system, or states a limitation that is not scientifically accurate (e.g., 'our model is smaller'). The argument does not reference oceans, atmosphere, land surface, or the sun as components of the Earth system.
Dimension: DCI
Developing: Student's model and argument correctly name three or more water cycle processes (evaporation, condensation, precipitation, and at least one of: runoff, infiltration, transpiration) and arrange them in a cycle. The argument references the sun as an energy source and the atmosphere as a pathway for water vapor, connecting the physical model to at least one real Earth system component. However, the student treats the water cycle as a fixed, unchanging system and does not address how changes in one part of the system (e.g., temperature increase) would affect other parts. The Step 6 extension prediction is made but is not connected to the Earth system mechanism (e.g., 'if temperature goes up, there will be more rain' without explaining the chain of system changes).
Proficient: Student's revised model accurately represents the water cycle as a continuous Earth system process driven by solar energy, showing: evaporation from ocean/land surfaces, transport of water vapor through the atmosphere, condensation forming clouds, precipitation returning water to Earth's surface, and collection/runoff returning water to the ocean. The argument explicitly connects the physical model results to the real Earth system scale, naming the sun as the energy driver analogous to the lamp, the atmosphere as the medium for vapor transport analogous to the air space in the bin, and Earth's surface as the collection reservoir. The Step 6 extension identifies at least one specific model limitation (e.g., 'our model has no wind to transport water vapor horizontally, but in Earth's atmosphere, air circulation moves water vapor from oceans to land') and makes a justified prediction about the effect of temperature increase on evaporation rates that references the Earth system mechanism.
Procedure
Step: 1
Title: Observe the Phenomenon and Build an Initial Model
Deliverable: Each student's individual initial model sketch (collected) plus one group consensus initial model posted on the board with labeled arrows and two written 'puzzling questions.'
Description: Teams watch the 2-minute terrarium time-lapse video twice. Each student sketches an initial model diagram showing where water goes and why, labeling arrows with their best current explanation. Teams then share diagrams and create one consensus group initial model on a large sticky note or whiteboard section, annotating each arrow with a proposed cause (e.g., 'heat from sun causes water to leave soil'). Groups record at least two 'puzzling questions' the model cannot yet answer.
Evidence To Collect: Teacher photographs group initial models and collects individual sketches to assess prior conceptions and identify which cause-and-effect relationships students already recognize versus which are missing or incorrect (e.g., missing energy as the driver of evaporation, or treating condensation as water appearing from nowhere).
Step: 2
Title: Design and Set Up the Physical Model Investigation
Deliverable: Completed investigation planning sheet including: written prediction with cause-and-effect rationale, labeled diagram of the physical model setup, identified variables table (independent, dependent, controlled), and a data table template with correct units.
Description: Each group receives a materials kit: two identical clear plastic bins with lids, warm water (measured volume: 200 mL), cold water (200 mL), a thermometer, a ruler, plastic wrap, tape, a lamp (heat source), ice packs, and a graduated cylinder. Groups are told the testable question: 'How does water temperature affect the rate of water vapor transfer (condensation on the lid) in our model water cycle?' Students write a prediction with a cause-and-effect rationale ('We predict ___ because ___'), identify the independent variable (water temperature: warm vs. cold), dependent variable (amount of condensation collected on lid per 10 minutes, measured in mL), and at least two controlled variables (same volume of water, same lid material, same room temperature, same time interval). Students record their plan in a structured investigation sheet before setting up both bins simultaneously.
Evidence To Collect: Teacher reviews planning sheets before students begin setup to check that: (1) the prediction references a cause-and-effect mechanism tied to energy/temperature, (2) controlled variables are genuinely controlled in their physical setup, and (3) the data table is structured to capture quantitative measurements at timed intervals.
Step: 3
Title: Collect Quantitative Data
Deliverable: Completed quantitative data table with condensation volume (mL) and water temperature (°C) recorded at three time intervals for both conditions, plus calculated totals and averages.
Description: Groups run both model setups (warm-water bin under lamp, cold-water bin with ice pack) simultaneously for three 10-minute intervals. Every 10 minutes, students carefully tilt each lid and drain condensation into a graduated cylinder, recording the volume in mL. They also record water temperature in each bin using a thermometer at each interval. All measurements are entered into the shared data table. Groups calculate the total condensation collected for each condition and the average condensation per interval. At least one student acts as a recorder, one as a measurer, and one as a timer, with roles rotating each interval.
Evidence To Collect: Teacher collects data tables and checks for: correct units on all measurements, internally consistent data (warm condition should yield more condensation), accurate arithmetic in totals and averages, and evidence that multiple trials/intervals were used rather than a single measurement.
Step: 4
Title: Analyze Data and Revise the Model
Deliverable: Hand-drawn or digitally created bar/line graph with labeled axes; revised annotated model diagram with legend and star markings; written model revision note.
Description: Groups create a bar graph (or line graph if they prefer) comparing total condensation collected in the warm vs. cold condition, with properly labeled axes and a title. Students then return to their group initial model diagram from Step 1 and produce a revised model. The revised model must: (a) add or correct arrows to show the full water cycle pathway, (b) annotate each arrow with the specific cause that drives that movement (referencing energy/temperature from their data), (c) use a legend to distinguish liquid water, water vapor, and energy, and (d) mark with a star (*) every place their data changed or confirmed their original thinking. Groups write a 2-3 sentence 'model revision note' explaining what they changed and why.
Evidence To Collect: Teacher assesses whether the graph accurately represents the quantitative data, whether the revised model now correctly shows energy (heat) as the cause of evaporation and the temperature difference as the cause of condensation, and whether the model revision note connects data evidence to specific changes in the model rather than making general statements.
Step: 5
Title: Construct a Scientific Argument and Peer Review
Deliverable: Individual written Claim-Evidence-Reasoning argument (minimum 1 page); completed peer review checklist for the other group's argument; a one-sentence written note describing one revision made based on peer feedback.
Description: Each student individually writes a structured scientific argument (Claim-Evidence-Reasoning format) responding to the driving question. The claim must answer what drives water to move continuously through Earth's systems. Evidence must cite at least two specific quantitative data points from their investigation (e.g., 'The warm-water bin produced an average of X mL of condensation per interval, compared to Y mL in the cold-water bin'). Reasoning must explain the mechanism — how energy input causes evaporation, how cooling causes condensation, and how these processes link to form a continuous cycle in Earth's systems. After writing, groups exchange arguments with another group for structured peer review using a provided checklist (Does the claim directly answer the question? Is evidence quantitative and specific? Does the reasoning explain the cause-and-effect mechanism?). Writers revise based on at least one piece of peer feedback, noting what they changed.
Evidence To Collect: Teacher collects all written arguments and peer review checklists. Proficient arguments will name energy/heat as the cause of evaporation, cite specific mL values from the data table, and explain the mechanism connecting temperature difference to condensation — not just describe the sequence of events. Teacher also checks that the revision note reflects genuine engagement with peer feedback.
Step: 6
Title: Connect Model to Real Earth Systems and Reflect
Deliverable: Written responses to both extension prompts (3-5 sentences each); completed self-assessment rubric.
Description: Groups discuss and then each student individually responds in writing to two extension prompts: (1) 'Our model left out some parts of the real water cycle. Identify one limitation of our physical model and explain how the real Earth system is more complex.' (2) 'Based on your data and model, predict what would happen to the rate of evaporation from Earth's oceans and lakes if average global temperatures increased by 2°C. Use your cause-and-effect model to justify your prediction.' Students also complete a self-assessment rating their own proficiency on each of the three dimensions (SEP, CCC, DCI) using the rubric language.
Evidence To Collect: Teacher reviews extension responses to assess whether students can transfer their cause-and-effect model to the real Earth system scale, identify model limitations (e.g., no wind, no transpiration, no runoff), and make a justified prediction about the effect of temperature change on evaporation rates — demonstrating understanding of the water cycle as an Earth system process driven by energy.
Phenomenon
When a sealed glass terrarium containing moist soil and plants is placed near a sunny window, water droplets appear on the inside of the glass within minutes, then drip back down to the soil — even though no new water was added. Students observe a time-lapse video showing this happening in a real terrarium over 24 hours, watching condensation form, collect, and 'rain' back down repeatedly.
Task Scenario
You and your team are junior Earth systems scientists at a water resource research center. Your director has shown you footage of a sealed terrarium that keeps cycling water on its own, and local city planners are asking your team a bigger question: if temperatures in your region rise due to climate change, how will that affect the water cycle that feeds local rivers and reservoirs? Before you can advise the city, you need to understand the mechanism behind the water cycle itself.
Over the next three class periods, you will build a physical model of the water cycle using simple materials, collect quantitative data on how a key variable (temperature) affects the rate of evaporation and condensation, revise your model diagram to show cause-and-effect relationships, and construct a written scientific argument explaining the mechanism that drives water movement through Earth's systems. Your final products will be shared with another team for peer review before being submitted to your 'director.'
Teacher Notes
Scaffolding
For Step 1 initial models, provide a word bank of process names (evaporation, condensation, precipitation, runoff, transpiration, infiltration) and a list of Earth system components (ocean, atmosphere, land surface, clouds, rivers) so that language barriers do not prevent students from demonstrating conceptual understanding.
For Step 2 variable identification, provide a 'Variable Sort' card set with 12 cards listing potential variables (water volume, water temperature, lid material, room temperature, light intensity, time, container size, etc.) that students physically sort into independent, dependent, and controlled categories before writing their plan.
For Step 3 data collection, provide a pre-formatted data table template with column headers, units already filled in, and a reminder box stating 'Record to the nearest 0.1 mL' to reduce cognitive load during measurement so students can focus on accuracy.
For Step 5 argument writing, provide a sentence frame scaffold for students who need it: 'Our claim is that ___. Our evidence includes [data point 1: ___ mL at ___°C] and [data point 2: ___ mL at ___°C]. This evidence supports our claim because [mechanism: when ___ increases, ___ causes ___, which leads to ___].' Students should be encouraged to move beyond the frames as they gain confidence.
For English Language Learners and students with IEPs, allow the revised model diagram (Step 4) to serve as a partial substitute for written argument text — students can annotate their model with cause-and-effect labels and then write a shorter argument that references the model explicitly.
For advanced students who finish early, provide the extension challenge: 'Design a modified version of your physical model that also represents transpiration from plants. Draw a diagram of your modified model and explain how adding transpiration would change the amount of condensation you would collect.'
Misconceptions
Students often believe water 'disappears' during evaporation rather than changing state and entering the atmosphere as invisible water vapor — they may draw evaporation arrows that simply end, rather than connecting to the atmosphere as a reservoir.
Students frequently treat condensation as water appearing from nowhere ('the cold surface makes water') rather than understanding that water vapor already present in the air loses energy and changes state when it contacts a cooler surface.
Many students believe the water cycle is driven by gravity alone (water falls down, then somehow goes back up) without recognizing solar energy as the primary driver of evaporation — the investigation is designed to make this visible by manipulating temperature.
Students at this grade band often conflate correlation with mechanism: they may correctly observe that 'warm = more condensation' without explaining WHY (increased thermal energy → increased molecular kinetic energy → more molecules escape liquid surface). The reasoning section of the argument is specifically designed to push past correlation.
Students may think the water cycle is a perfect closed loop that always stays the same, not recognizing that changes in temperature or land use can alter the rates of different processes and shift water distribution across reservoirs.
Proficiency Indicators
A proficient revised model diagram (Step 4) will show a closed loop with at least four labeled process arrows, each annotated with a cause that references energy or temperature, a three-symbol legend, and at least two star markings with corresponding written justification citing specific data values.
A proficient written argument (Step 5) will name energy transfer as the mechanism in the claim, cite at least two specific mL values from the data table, and explain both the evaporation mechanism (thermal energy → molecular escape) and the condensation mechanism (energy loss → state change) in the reasoning — not just list them as sequential events.
Proficient data tables (Step 3) will show measurements at all three time intervals for both conditions, with temperature and condensation volume both recorded, and will include calculated totals and averages with correct units throughout.
A proficient Step 6 extension response will name a specific model limitation that is scientifically accurate and relevant (not just 'it's smaller') and will make a prediction about the effect of temperature increase that chains at least two cause-and-effect steps together using Earth system vocabulary (evaporation rate, water vapor, atmosphere, precipitation).
During Step 2 group discussion, listen for students who can articulate WHY they are controlling specific variables — proficient students will say something like 'We need to keep the water volume the same so we know any difference in condensation is caused by temperature, not by having more water to evaporate' rather than just listing controlled variables without justification.
Ngss Alignment
Cccs
Cause and effect: Mechanism and explanation
Seps
Developing and using models
Grade Band: 6-8
Dci Category: Earth & Space Sciences
Dci Sub Strand: Earth systems
Driving Question
How can we build and use a model to explain what causes water to move continuously through Earth's systems — and what happens to that movement when conditions change?