Traveling on the Water Cycle

Transcription

1 Traveling on the Water Cycle 40- to minute sessions ACTIVITY OVERVIEW 62 M OD E L I N G Students simulate traveling with water molecules through the water cycle, beginning in their own town. After first choosing a starting point in the water cycle, students roll a number cube to determine where the water will go next. After making at least six stops, students write a story that describes traveling with their water, which will demonstrate their understanding of the processes of the water cycle. KEY CONCEPTS AND PROCESS SKILLS (with correlation to NSE 5 8 Content Standards) 1. Creating models is one way to understand and communicate scientific information. (Inquiry: 1) 2. The water on earth can be found as a solid, a liquid, and a gas. (PhysSci: 1) 3. Water circulates through the earth s crust, oceans, and atmosphere in the water cycle. It evaporates from the surface, rises, cools at higher elevations, condenses as rain or snow, and falls to the surface where it collects in lakes, oceans, soil, and rocks underground. (EarthSci: 1) KEY VOCABULARY clouds condensation evaporation model organisms precipitation water cycle water vapor E-127

2 Activity 62 Traveling on the Water Cycle MATERIALS AND ADVANCE PREPARATION For the teacher 1 Transparency 62.1, Sample Response to Analysis Question 2 1 Scoring Guide: ORGANIZING SCIENTIFIC IDEAS (SI) 1 transparency of Student Sheet 62.1, Anticipation Guide: The Water Cycle (optional) * pictures of the water cycle (optional) * 1 1-L container (optional) * 1 50-mL graduated cylinder (optional) * 1 overhead projector For each pair of students 1 set of six Water Cycle Cards 1 number cube For each student 1 Student Sheet 62.1, Anticipation Guide: Traveling on the Water Cycle 1 Student Sheet 62.2, My Water Cycle Story 1 Student Sheet 62.3, Story Ideas (optional) 1 Scoring Guide: ORGANIZING SCIENTIFIC IDEAS (SI) (optional) *Not supplied in kit You might want to laminate the Water Cycle Cards to withstand rough handling. Your decision on how you want students to complete the activity will determine any additional preparations. The activity is written for each pair of students to have their own set of Water Cycle Cards so they can do their traveling while remaining in their seats. Instead, you could set up water-cycle stations around the room, one for each different Water Cycle Card. Students then move around the room from station to station. You will need to label each station and equip it with at least one of the appropriate Water Cycle Cards and, if possible, pictures of scenes that depict that state in the water cycle. Assigning student teams to a beginning station works better than letting them choose their own. Masters for Scoring Guides are in Teacher Resource III: Assessment. TEACHING SUMMARY Getting Started 1. (LITERACY) Use Student Sheet 62.1 to elicit students ideas about the water cycle. Doing the Activity 2. Students simulate a journey through the water cycle. Follow-Up 3. Review the water cycle. 4. (LITERACY, SI ASSESSMENT) Students write a story describing the journey of their water.i E-128

3 Traveling on the Water Cycle Activity 62 TEACHING SUGGESTIONS GETTING STARTED 1. (LITERACY) Use Student Sheet 62.1 to elicit students ideas about the water cycle. Hand out Student Sheet 62.1, Anticipation Guide: Traveling on the Water Cycle. Students record on it their initial ideas about the water cycle by labeling places that contain water and drawing arrows showing water s possible movements. If students are having difficulty, have them work in pairs. Another option is to have students draw their own ideas about the water cycle by asking them how water moves around the earth instead of using the Student Sheet. If you choose this option, you may want to remind them to consider different surface materials of earth as well as the atmosphere. Ask, What are the different forms of water found on earth? Having constructed a concept map about water in a previous activity, students are likely to have many suggestions, such as rain, snow, seawater, and ice. If they do not suggest the different states (solid, liquid, vapor), ask them to group their suggestions under these three headings. Have the class read the introduction to the activity, and review with them what a water molecule is. Note that it is not necessary for them to understand the chemistry of a water molecule to complete this activity. Explain that during this activity each student will take an imaginary journey with water molecules that are traveling on the water cycle. They will start at their own town, and along the way, they will gather information to use to write a story describing the adventures of their water. DOING THE ACTIVITY 2. Students simulate a journey through the water cycle. If necessary, review the procedure with the class. Note that one of the cards is titled Organisms ; if necessary explain that organisms are living things, from single-celled bacteria to multicellular elephants. Emphasize that while a water molecule must go to the general location defined by the roll of the number cube (such as the atmosphere), students can choose to have their molecules be in any state or place within the general location and are not restricted to choosing one of the descriptions listed on the cards. They may designate different specific locations where a drop of water might be, such as a drainpipe or a tree near a river. Distribute Student Sheet 62.2, My Water Cycle Story, to each student, and have them complete the first three columns. You might complete the the first row with them to get them started. For example, tell them that the water molecules start as precipitation, and so they would record the card title Precipitation in the first column. From there it is up to each pair of students to decide what type of precipitation the water molecules are a part of. If they select rain, they would record rain in the second column, and liquid in the third column. Point out that of the places water can be found on the Organisms card, a large percentage is contained in the cells and tissues of plants, animals, and other organisms. Distribute a number cube and a set of six Water Cycle Cards to each pair of students. (Or organize students at different stations throughout the room, and have students actually travel among them.) Each student should move through at least six rounds of the water cycle. Inform students that it is not necessary for them to go to each of the different locations described on the different Water Cycle Cards. Some students, for example, may end up at Precipitation three times and never arrive at the Organisms, Groundwater, or Land cards. Since this activity models the water cycle, it is structured so that students will use certain locations of water more frequently than others; this parallels the situation on earth, where a higher percentage of water is found in one place (the oceans) than in another. Finally, guide students through completing the last column on Student Sheet Begin by instructing them to follow Procedure Step 7 to identify the exact E-129

4 Activity 62 Traveling on the Water Cycle location of water molecules and how they traveled from place to place. You might provide Student Sheet 62.3, Story Ideas, for students to consult. A sample response is shown below. FOLLOW-UP 3. Review the water cycle. Have students individually complete Analysis Question 1 using Student Sheet Then use Transparency 62.1, Sample Response to Analysis Question 2, to begin to review the water cycle, or use a transparency of Student Sheet 62.1 to record students answers and construct a model response. Emphasize that water can and does constantly move, or cycle, not only from place to place, but all over earth. It changes from vapor, to liquid, or solid over and over again in no particular order through evaporation, condensation, melting, and freezing. Ask, How does water move from one place to another? It can move from place to place in all three of its states, falling as precipitation, being blown as part of a cloud, or as a flowing in a river or ocean current. Most of the water on earth today has been here for billions of years and has most likely been in each of the places on the water cycle many millions of times, hence the word cycle in the water cycle. After reviewing the water cycle, use Analysis Questions 2 and 3 to discuss how well the activity and the diagram on Student Sheet 62.1 act as models of the water cycle. One way to accomplish this is by having students compare their water cycles with the distribution of water on earth, as described in the introductory text in the Student Book. You might model this illustration by filling a 1-L container with water and removing 30 ml (3%) to represent the amount of earth s freshwater. Ask, Did the number and location of the different water cycle cards reflect the fact that the majority of the world s water is found in the oceans? This was a limitation of the model, because exploring different aspects of the water cycle meant decreasing the emphasis on the oceans. Did the roll of the number cube place you in the ocean more than in other places? Many of the cards led to the ocean more often than other places, indicating an emphasis on water in the oceans. See also the Suggested Response to Analysis Question (LITERACY, SI ASSESSMENT) Students write a story describing the journey of their water. Analysis Question 4 provides an opportunity for students to develop their notes from Student Sheet 62.2 into a complete story. Provide guidance for story writing. Depending on your goals and whether or not this story-writing exercise is done in conjunction with a language arts teacher, you might discuss with your students the writing steps that are summarized below. The last two steps (revising and editing) are usually not done in classrooms, yet they are important not only in helping students write good stories, but in making sure they have fully understood the concepts their stories are intended to illustrate. Sample Response to Student Sheet 62.2, My Water Cycle Story Card Title My water molecules are a part of: This water is in what state (solid, liquid, or gas)? Describe how your water could have changed or moved from the previous row to this one. 1. Precipitation rain liquid 2. Ocean iceberg solid The rain ran into a flooded river that eventually led to the Arctic Ocean. The water froze onto an ice sheet in the Arctic. 3. Atmosphere wind gas (water vapor) Warm wind blew across the ice sheet and some of the water melted and evaporated into the atmosphere. E-130

5 Traveling on the Water Cycle Activity 62 Pre-Writing: Thinking about and organizing your ideas Drafting: Writing your thoughts down in sentences and paragraphs Revising: Rewriting the story, sometimes based on the suggestions from other people Editing: Proofreading for spelling, punctuation, and grammar You may use this story-writing assignment to assess students ability to organize scientific ideas. If you do so and if you use the ORGANIZING SCIENTIFIC IDEAS (SI) Scoring Guide, you should review your expectations with the class and give each student a copy of the expectations before they begin their drafts. Suggested criteria are listed below: The water molecules you travel with should change locations at least five times in the story. You should describe how water moves from one place to another and demonstrate an understanding of how water changes to become a gas, a liquid, and a solid. You should identify any changes that occur in the state of the water. Your story should have a clear beginning, middle, and end. You can include illustrations that relate to your story. SUGGESTED ANSWERS TO QUESTIONS 1. On Student Sheet 62.1, you recorded your initial ideas about the water cycle. To complete Student Sheet 62.1: a. Use the following words to identify where water can be found in the picture: atmosphere groundwater land ocean organisms precipitation b. Draw at least six arrows showing the likely movement of water from one place to another. c. Label places where each of the following is occurring: condensation evaporation freezing melting See Transparency 62.1, Sample Response to Analysis Question 2. d. What changes did you have to make to your student sheet so that you could complete it? Students answers will vary. Common changes include having to address water in groundwater and organisms (including both trees and cows); having to add more arrows showing water movement; and labeling condensation, evaporation, freezing, and melting (which were not part of the original instructions). 2. The term water cycle is used to describe the movement of water on the earth. Do you think that your diagram on Student Sheet 62.1 is a good summary of the water cycle? Why or why not? The diagram shows most parts of the water cycle, but does not clearly represent a cycle in the sense of a circle. 3. In this activity, you used cards and number cubes to model the water cycle. Do you think that this activity was a good model of the water cycle? Why or why not? It was a good simplified model of the water cycle. It highlighted the most common places water is found. The return trips to particular locations, such as the ocean, reflected the general distribution of water among different parts of the earth. The limitations of the model were that they did not include every location where water can be found and did not provide all the possibilities of water movement (for example, the Atmosphere card led to Precipitation, Organisms, and Atmosphere, but not to Oceans). E-131

6 Activity 62 Traveling on the Water Cycle 4. (SI ASSESSMENT) Expand your notes from Student Sheet 62.2 into a story that describes the journey of your water molecules. Your story should follow your water through at least five places. Be as creative and scientifically accurate as you can! Be sure to: Describe or draw how your water moved from one place to another. Identify any changes in state (solid, liquid, gas) that occur. Level 3 Response: There was a freezing rainstorm in our town. It formed icicles on the antennas of cars. When the hailstorm stopped, the icicles melted into liquid water which flowed into the ocean. The ocean water evaporated into water vapor, rising until it reached high in the atmosphere. Some time later, it condensed and precipitated onto a lake. A horse drank from the lake and started to sweat. At that point, the water was a liquid on the skin of a sweaty horse. It eventually evaporated and precipitated onto the Arctic Ocean. The water froze and became part of a glacier that was floating in the middle of the ocean. E-132

7 Sample Response to Analysis Question The Regents of the University of California Atmosphere Atmosphere Atmosphere Condensation Condensation Precipitation Precipitation Evaporation Land Freezing Melting Organisms Land Organisms Evaporation Land Ocean Groundwater Rock layers 2562 LabAids SEPUP Issues Earth Sci TG Figure: EaTG 62.02Trans LegacySansMedium 10/11.5 Issues and Earth Science Transparency 62.1 E-133

8 Name Date Anticipation Guide: The Water Cycle 2006 The Regents of the University of California 2562 LabAids SEPUP Issues Earth Sci TG Figure: EaTG 62.01SS LegacySansMedium 10/11.5 Issues and Earth Science Student Sheet 62.1 E-135

9 Name Date My Water Cycle Story Card Title My water molecules are a part of: This water is in what state (solid, liquid, or gas?) Describe how your water could have changed and/or moved from the previous row to this one The Regents of the University of California Issues and Earth Science Student Sheet 62.2 E-137

10 Name Date Story Ideas My water molecules are: Atmosphere part of a dark rain cloud above my town in the wind blowing over some mountains rising in warm, wet air over the ocean Groundwater slowly dripping through layers of rock after a flood frozen in the middle of layers of soil seeping into the bottom of a deep well in my town Ocean floating in the middle of the ocean in a gentle wave hitting the beach in my town flowing in a current from Florida to Georgia Organisms evaporating off of the leaf of a plant in the exhaled breath of a town resident on the skin of a sweaty horse 2006 The Regents of the University of California Precipitation part of the rain that has been pouring down in my town in the snow that is falling on mountaintops forming icicles along the roof edge of a building Land in the river that is flooding my town floating in the middle of a large lake forming a small puddle on the sidewalk Issues and Earth Science Student Sheet 62.3 E-139