Lesson 3. Cycling of Water

Lauren Levites, Umit Aslan, Shruti Researcher
Biology, Environmental Science
60
High School
v5

Overview

In this lesson students analyze a demonstration of the water cycle in a bag. Prior to the lesson, have students observe you (or do themselves): Set up a cup with water and food coloring, seal this cup in a gallon size ziploc bag. Seal the bag, with the cup nestled in the corner, and tape it to a sunny window.

In this lessons students are introduced or reminded of some basic chemistry: Phase changes (liquid to gas, gas to liquid) and molecules of matter (water and "food coloring").

After a few days students see the water has evaporated from the cup and condensed in the bag, they will see a cup with colored water and clear water in the bottom of the bag.

Students will draw simple model to trace the movement of matter (2 types of matter here). Their models should show 1 type of matter, water, evaporating and condensing, while the other type of matter "food coloring" does not.

Students then use a simple water cycle interactive to build off on the evaporation-condensation model. Key processes to highlight are runoff, infiltration/percolation, and repetition of steps.

Standards

Next Generation Science Standards
  • Earth and Space Sciences
    • [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.
  • NGSS Crosscutting Concept
    • Patterns
    • Energy
    • Stability and Change
  • NGSS Practice
    • Analyzing Data
    • Constructing Explanations, Designing Solutions
    • Using Models
    • Conducting Investigations
Computational Thinking in STEM
  • Data Practices
    • Analyzing Data
    • Collecting Data
    • Visualizing Data
  • Modeling and Simulation Practices
    • Using Computational Models to Understand a Concept
    • Constructing Computational Models
  • Systems Thinking Practices
    • Understanding the Relationships within a System

Activities

  • 1. Water Cycle Demo
  • 2. Chemistry Basics
  • 3. Tracing Matter Model
  • 4. Water Cycle Expanded

Student Directions and Resources


We are building off of the demonstration of the water cycle to investigate what is happening to water in the Great Lakes system. 

In this lesson you will have a chance to think about the steps of the water cycle and what is happening in the system. You will also create an initial model in Sage Modeler and use simulation features to think about our phenomena of climate change in the Great Lakes.

1. Water Cycle Demo


In class, you looked at a cup of water with food coloring sealed in a ziploc bag and placed in the window. 


Question 1.1

List the components of the system of the cup sealed in the bag. 



Question 1.2

Describe the transfer of matter in the bag: Where did it start, where did it end? Did all the matter transfer? Did all types of matter transfer?



Question 1.3

What was the energy source that facilitated the transfer of matter?

2. Chemistry Basics


The changes you saw in the bag on a macroscopic scale are due to changes at the microscopic scale. 

As the water moves from the cup and into the bottom of the sealed plastic bag, we are witnessing changes in matter and energy.  On the first page, we determined that the energy source present here is the sun. The water in this demonstration is moving through 2 phases of the water cycle. 

In order for matter to move, it must change state. The three major states of matter are solid, liquid and gas. The specific molecules here are present in liquid or gas form. 

Think about what molecules of matter are moving, where are they moving to, and if there is matter that does not move. 


Question 2.1

Make a list of types of molecules that are present in this system. Next to each, write if they are a gas or liquid. It may be possible to have the same molecule in both states. 



Question 2.2

What evidence do you have that the water moved from a liquid to a gas?



Question 2.3

Which process did this step represent?

  evaporation
  condensation
  precipitation
  runoff


Question 2.4

What evidence do you have that the water changed from a gas to a liquid?



Question 2.5

Which process did this step represent?

  evaporation
  condensation
  precipitation
  runoff


Question 2.6

Which molecules in this system didn't move?

3. Tracing Matter Model


Draw a model to trace matter in the demonstration. Use the key on the model to show where matter is. Use amounts of a symbol to show proportion, such as the same amount, more of one than the other, etc. 


Question 3.1

Add to the model below to show the transfer of matter in this demonstration. Use the key provided to show the molecules of matter. Select a certain number to show proportion or ratio of molecules. Be sure to identify if ratios change. 

Note: Draw your sketch in the sketchpad below


4. Water Cycle Expanded


Use the image of the water cycle below.

 


Question 4.1

Why do you think this image repeats a process, like evaporation? What does that mean about what is happening in our atmosphere?



Question 4.2

Look for runoff on the image. Using the image, describe what runoff is. Give an example where you have seen runoff before.



Question 4.3

In what instances is liquid water changing into water vapor? Besides evaporation, what other processes are involved here?



Question 4.4

One process that isn't on this diagram is flooding. Draw on the diagram to add flooding where you think it should go on this diagram.

Note: Draw your sketch in the sketchpad below