# 5.4: Enrichment

Difficulty Level: At Grade Created by: CK-12

## Enrichment 4-1: Teacher Activity Notes

What Goes Up Must Come Down-Water Cycle Simulation

### PLAN

Summary

Students observe water evaporating and condensing within closed containers to learn about a portion of the water cycle.

Objectives

Students:

\begin{align*}\checkmark\end{align*} identify the relationship between evaporation and condensation in the water cycle.

\begin{align*}\checkmark\end{align*} evaluate the effects of different environmental conditions on the rate of evaporation and/or rate of condensation.

Student Materials

Per Student

• Activity Guide
• Activity Report

Per Group

• 3 containers with clear plastic lids (such as take-out food containers)
• 3 small cups (such as 8 oz. tubs for soft margarine)
• Permanent marking pen; Plastic spoon; Water; Salt
• Food coloring (green, blue, or red)

Teacher Materials

One week before doing this activity ask your students and neighbors to collect clear plastic containers from fast food restaurants or from food purchased at grocery stores.

Estimated Time

One 50-minute period to setup the containers

Allow a few minutes over several days for students to observe the containers and record their observations.

Prerequisites and Background Information

Students should be familiar with the terms evaporation and condensation.

Heat increases the kinetic energy of water molecules. This causes them to move faster and increases the rate of evaporation. Thus, when the containers are in a warm, sunny place, the rate of evaporation should increase. Cold temperatures decrease the kinetic energy of water molecules. This causes them to move slower, which increases the rate of condensation. Thus, when the containers are in a cool, damp place, the rate of evaporation should decrease.

Water molecules are continually moving between locations from the “lake” in the cup to the droplets on the inside of the lid. The changing of water from a liquid to a vapor is called a phase change and is associated with a corresponding energy change. Water molecules are also moving between droplets. Water molecules have a tendency to condense into larger droplets. This condensation is due to a lower average energy level of water molecules in the larger droplets. That is, there is less surface energy per unit volume in the larger droplets.

### IMPLEMENT

Introduce Enrichment 4-1 by reviewing with students the difference between evaporation and condensation. Ask students to give you evidence from their personal experiences that water evaporates and condenses. Some examples are descriptions of how puddles disappear a day after it rains (evaporation) or how water drops form on the outside of a glass of ice water (condensation).

Steps 1-6 Have students work in pairs to set up the experiments as shown in Steps 1 to 6 of Enrichment 4-1. The illustrations should help students construct the containers without your assistance. Remind students to label the different containers.

Steps 7-9 Have students make and record their observations several times during the day or at a certain time each day for a week. You may want them to record their observations and drawings in a data book.

• Students should first observe small droplets of water condensing directly above the small cup of water and then spreading outwards to the edges of the clear plastic top of the larger container. Students may observe a gradation in the size of the water droplets-with the larger droplets appearing directly over the small container and the smaller ones visible near the edges. This would be an ideal opportunity to discuss with students why these size differences occur. See the description in the background information above.
• Container B, salt water: Water will evaporate from this solution, leaving behind a more concentrated salt solution. You may want to explain that this is the principle behind evaporating ponds that are used to concentrate sea salt. This method can also be used to obtain potable water from salty water.
• Container C, colored water: Again, clear water will evaporate, leaving colored water in the container. Unless a material can vaporize (change from liquid to gaseous form), it will remain in the water. This concept can be related to salt and mineral buildup in agricultural lands resulting from the use of certain fertilizers and other products in the water.

Make sure students answer the questions on the Activity Report.

Conclude Enrichment 4-1 by holding a class discussion of the questions on the Activity Report.

Extend Enrichment 4-1 by having students explain how changes in temperature can account for the formation of steam, snow, or humidity. Encourage students to test their ideas by actually changing the conditions of the containers such as opening the lids of the containers or placing paper around the outside of the containers.

### ASSESS

Use the water cycle simulation experiment to assess if students can

\begin{align*}\checkmark\end{align*} explain the critical role that evaporation and condensation play in the water cycle.

\begin{align*}\checkmark\end{align*} describe the phase changes that water undergoes (liquid to vapor and vapor to liquid).

\begin{align*}\checkmark\end{align*} demonstrate the effects of different environmental conditions on their experimental model.

\begin{align*}\checkmark\end{align*} make predictions and designing tests to verify the predictions.

\begin{align*}\checkmark\end{align*} compare and contrast their model and the water cycle in their community.

## Enrichment 4-1: What Goes Up Must Come Down-Water Cycle Simulation – Activity Report Answer Key

• Sample answers to these questions will be provided upon request. Please send an email to teachers-requests@ck12.org to request sample answers.

1. Which two parts of the water cycle were shown in this activity?
2. What is the energy source for the water cycle?
3. What could you do to cause the water to leave the air and return to the bottom of the container?
4. Since the contents of each container were different, what predictions can you make about the water droplets in each container? Give reasons for your answers.
5. How could you test to see whether your predictions are correct?
6. How does the water cycle in your community affect your life?

## Enrichment 4-1 Activity Guide: What Goes Up Must Come Down-Water Cycle Simulation (Student Reproducible)

Introduction

The water cycle is an essential part of our lives. Water moves through our atmosphere during the processes of evaporation, condensation, precipitation, and transpiration. In this activity you construct a model of water moving through the water cycle. As you watch the cycle in progress, remember what you learned about water molecules. Remember how they move apart or evaporate and how they collect together or condense so we have water for life.

Materials

• 3 containers with clear plastic lids (such as take-out food containers)
• 3 small cups (such as 8 oz. tubs for soft margarine)
• Permanent marking pen
• Plastic spoon
• Water
• Salt
• Food coloring (green, blue, or red)
• Activity Report

Procedure

Step 1 Mark each small cup clearly with A, B, or C.

Step 2 Fill each of the three small cups half full of water.

Step 3 Place cup A inside the larger plastic container. Tightly close and tape the clear plastic lid shut.

Step 4 Add a teaspoon of salt to cup B and stir to dissolve the salt. Place cup B into a larger container and tightly close and tape the lid shut.

Step 5 Add two drops of food coloring to cup C. Place this cup into a larger container and tightly close and tape the lid shut.

Step 6 Your three experiment containers should look like this.

Step 7 You will put your containers first in a shady, cool place to observe what happens. Then you will put them in a sunny, warm place to observe what happens. Make predictions or form hypotheses stating what you expect to observe. Explain the reasoning behind your predictions or hypotheses.

Step 8 Place all three containers in a shady, cool place and observe frequently over a period of several hours or days. Record your observations including drawings or photos of any changes.

Step 9 Repeat Step 8 in a sunny, warm place.

## Enrichment 4-1 Activity Report: What Goes Up Must Come Down-Water Cycle Simulation (Student Reproducible)

1. Which two parts of the water cycle were shown in this activity?

2. What is the energy source for the water cycle?

3. What could you do to cause the water to leave the air and return to the bottom of the container?

4. Since the contents of each container were different, what predictions can you make about the water droplets in each container? Give reasons for your answers.

5. How could you test to see whether your predictions are correct?

6. How does the water cycle in your community affect your life?

## Enrichment 4-2: Teacher Activity Notes

Water Underground

### PLAN

Summary

Students examine the portion of the water cycle that occurs beneath the surface of the earth by constructing a model of the water cycle. Their water cycle model includes groundwater.

Objectives

Students:

\begin{align*}\checkmark\end{align*} explain the cycling of water, especially those portions that occur below ground.

\begin{align*}\checkmark\end{align*} compare a model of the water cycle to how water cycles on Earth.

Student Materials

Per group

• Activity Guide
• Activity Report
• Plastic drink bottle, empty (such as a 2-liter bottle)
• Cutting tools (single-edged razor blade in safety holder or scissors)
• Small metric ruler
• Beaker or cup
• Spoon
• Tape
• Paper towels
• Marking pen

Per class

• Balance or scale
• Gravel
• Clay (modeling or potter's clay)
• Potting soil, lightly moistened
• Water
• Food coloring (green, blue, or red)

Teacher Materials

One week before doing this activity have your students and neighbors collect empty plastic drink bottles.

A suggested reference book explaining how to work with plastic bottles is Bottle Biology, by P.H. Williams, published by Kendall-Hunt Publishing Company, 1993. This book describes how to fill the bottles with warm (not hot) water to facilitate removal of labels and base. Suggestions are also made for how to mark an even line for cutting-Place the bottle against the corners of a box lid. Hold a marking pen firmly at the desired location on the bottle. And rotate the bottle. This will give you a straight line to cut along.

Caution students to handle cutting tools carefully. Depending upon the needs of your students, an adult helper could be engaged to assist the students with the cutting during class. Another option is to cut the bottles before class.

Estimated Time

One 50-minute period to set up the containers

Allow a few minutes over several days for students to observe the containers and record their observations.

### IMPLEMENT

Introduce Enrichment 4-2 by asking students to give examples from personal experience showing that water goes beneath the earth's surface. You may want them to read Section 4 of the text before beginning this activity. If students have completed Activity 4-2, explain that they have already examined how water cycles above ground. Then, explain that now they will examine how water cycles beneath the ground.

Steps 1-11 Have students work in pairs to build the model. The illustrations in the activity should help students construct the model with minimal assistance from you. Some students may experience see page of water below the clay layer if the clay has not been molded carefully to the edges of the bottle. If such see page occurs students may need to be reminded to make notes for later incorporation into their analysis. They can also be asked to relate this to a real-life situation involving the water table.

Step 12 The bottle's top can either be inverted or replaced right side up. In either case the two portions of the bottle should be taped tightly together to make sure there is no leakage.

After the models are constructed have students make observations a few minutes each day for a week.

Steps 13-15 You may want students to record their observations and drawings in a data book. You may want to suggest that they look for condensation on the inside surface of the bottle and carefully watch and measure any changes of water level in the “lake.”

Conclude Enrichment 4-2 by assigning the questions from the Activity Report as written class work or homework. Then reconvene the whole class and discuss students' answers to the questions on the Activity Report.

Extend Enrichment 4-2 by

• Having students experiment with bottles of differing volumes. The amounts of gravel, clay, and potting soil will vary depending upon the size of the bottle used.
• Asking students to generate ideas about other experiments that could be done with the model they built. For example, some students may choose to remove the top and observe the effects on the level of the water table under varying conditions. Other students may experiment to find out how different kinds of materials affect the water table including different types of clay or plaster.
• Asking students to design a different model to demonstrate the same processes.

### ASSESS

Use the final product, the model of a water cycle, to assess if students can

\begin{align*}\checkmark\end{align*} describe the essential role of groundwater in replenishing the water cycle.

\begin{align*}\checkmark\end{align*} distinguish between the different types of soil conditions that affect groundwater.

\begin{align*}\checkmark\end{align*} demonstrate and explain the effects of different environmental conditions on their model.

\begin{align*}\checkmark\end{align*} compare and contrast their model and the water cycle on the earth.

## Enrichment 4-2: Water Underground – Activity Report Answer Key

• Sample answers to these questions will be provided upon request. Please send an email to teachers-requests@ck12.org to request sample answers.
1. Describe what you observed on the inside walls of the bottle.
2. Give an explanation for your observations.
1. Describe any observed changes in the level of the water in the lake.
2. How would you explain these changes?
1. Did you observe any changes in weight? Explain.
2. How does what happened to the model compare to the water cycle on Earth?
3. How does what happened to the model differ from the water cycle in your community?
4. Summarize what you have learned about the water cycle. Use diagrams if you wish.

## Enrichment 4-2 Activity Guide: Water Underground (Student Reproducible)

Introduction

What happens to rain when it falls on the ground? Is the rainwater that seeps into the ground still a part of the water cycle? To answer these questions you construct a model of the water table and discover how groundwater moves beneath the earth.

Materials

Per student

• Activity Report

Per group

• Activity Guide
• Plastic drink bottle, empty (such as a 2 liter bottle)
• Cutting tools (single-edged razor blade in safety holder or scissors)
• Small metric ruler
• Beaker or cup
• Spoon
• Tape
• Paper towels
• Marking pen

Per class

• Balance or scale
• Gravel
• Clay (modeling or potter's clay)
• Potting soil, lightly moistened
• Water
• Food coloring (green, blue, or red)

Procedure

Step 1 If necessary remove the plastic base and label from your plastic drink bottle using warm water to melt the glue.

Step 2 Mark your bottle for cutting about 2 centimeters (em) below the shoulder of the bottle.

Step 3 Using the scissors or other cutting tool, carefully cut on the line you have marked to separate the bottle into two parts.

Step 4 Place the bottle upright or in its plastic base.

Step 5 Put a layer of gravel about \begin{align*}2 \ cm\end{align*} deep in the bottom of the bottle. (If the bottle is in its plastic base, add gravel to a point \begin{align*}2 \ cm\end{align*} above the top of the base.)

Step 6 Form a \begin{align*}1-cm\end{align*} layer of clay on top of the gravel. Mold the clay carefully against the sides of the bottle so water will not be able to seep down below the clay layer.

Step 7 On top of the clay layer carefully add another layer of gravel about \begin{align*}3 \ cm\end{align*} deep.

Step 8 Above the gravel, use the moist potting soil to make a layer of soil about \begin{align*}4\end{align*} to \begin{align*}5 \ cm\end{align*} deep. Press the layers down gently but firmly.

Step 9 Now it is time to make a “lake” in your model so you can observe any changes in the water level. Use a spoon to carefully scoop out a hole \begin{align*}4\end{align*} to \begin{align*}5 \ cm\end{align*} wide and \begin{align*}3\end{align*} to \begin{align*}4 \ cm\end{align*} deep along the side of the bottle. Press the dirt at the bottom of the “lake” firmly against the wall of the bottle and make the bottom higher near the side of the bottle. Your model should now look like this.

Step 10 Fill a beaker or cup with water and add several drops of food coloring. Carefully add water to your “lake” until it is about half full. Use a paper towel to clean off any excess dirt or water from the bottle wall.

Step 11 The small metric ruler should be placed at the edge of the “lake” so you can quantify any changes in water level in millimeters. Make sure you can read the ruler from the outside of the plastic bottle.

Step 12 Invert the top of the bottle and tape the two bottle parts together tightly to seal your system tightly.

Step 13 Determine and record the weight of your bottle and its contents. Record your observations.

Step 14 Place the bottle in a cool, dark place. Observe, weigh, and record your results at the same time each day for a week.

Step 15 Next, move the bottle to a warm, sunny place. Observe, weigh, and record your results at the same time each day for a week.

## Enrichment 4-2 Activity Report: Water Underground (Student Reproducible)

1. a. Describe what you observed on the inside walls of the bottle.

b. Give an explanation for your observations.

2. a. Describe any observed changes in the level of the water in the lake.

b. How would you explain these changes?

3. Did you observe any changes in weight? Explain.

4. How does what happened to the model compare to the water cycle on Earth?

5. How does what happened to the model differ from the water cycle in your community?

6. Summarize what you have learned about the water cycle. Use diagrams if you wish.

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