WHERE DOES THE WATER GO IN THE WATER CYCLE?

Transcription

1 WHERE DOES THE WATER GO IN THE WATER CYCLE? OBJECTIVES Identify the water cycle as a system that is a combination of systems Describe each process in the water cycle, including the changes in state (if any) that water goes through during each process Explore where water is located on Earth, how much water is in each reservoir of the water cycle and how water moves from one place to another through the water cycle system TOPICS BACKGROUND MATERIAL Water cycle Water reservoirs Systems TEKS ALIGNMENT Grade 4 Science: 2D, 2F, 6A, 7C, 8B Earth is called the blue planet, and if you look at a world map you can get a pretty good impression of where Earth s water is found. Slightly over 97% of all water on Earth is found in the oceans. A little more than 2% is found as ice frozen in polar icecaps or in glaciers on mountaintops. Less than one-half of 1% of all water on Earth is found as liquid freshwater. This includes all of the water in all of the lakes, rivers and streams in the world (about 0.02%) and all of the water that is found underground (about 0.3%). The atmosphere contains only 0.001% of all water on Earth. Grade 5 Science: 2D, 2F, 3A, 3C, 6A, 8B But while the amount of water in each of these storage areas, or reservoirs, remains relatively constant over time, individual water molecules are constantly moving from one reservoir to another in a system known as the water cycle. The water cycle is not literally a circle, even though it is often shown as a circle in pictures. A cycle is a group of events that repeat themselves, and that is what the processes of the water cycle do. In the water cycle, water is neither created nor destroyed, it just moves to different reservoirs through a series of processes. Water moves very quickly through some parts of the water cycle, and it moves very slowly through others. The amount of time that water remains in a certain reservoir of the water cycle is called its residence time.

2 The water cycle is a type of system. A system is a collection of parts that act together to perform a task. The different parts of the system share matter and energy as they work together. In the case of the water cycle, the matter that is shared is water, and the energy that is shared is heat energy from the sun and gravitational energy. Systems can be made up of smaller units called subsystems, which are smaller units that share matter and energy with each other. In the water cycle, there are many subsystems comprised of processes that connect only a few reservoirs with each other. KEY TERMS Aquifer is an area where large amounts of water are stored underground in natural formations of sand, gravel or rock Drainage Basin is an area that includes a river, its tributaries and the surrounding land that drains water into them Glacier is a large area of ice and snow that has accumulated over many years Headwaters are the place where a stream or river begins Hydrosphere is all place on Earth where water is found, whether it is liquid water, ice or water vapor Reservoir is a place where a substance, especially liquid water, is stored Residence Time is the length of time water spends in any part of the water cycle before moving to another part Spring is a place where water flows out of the ground and becomes part of a stream or river Subsystem is a smaller system within a larger system System is a collection of parts that act together to perform a task. The different part of the system share matter and energy as they work together Tributary is a smaller stream that flows into a larger stream Watershed is all of the land area that drains water into a common point, usually a lake, river or stream

3 PROCEDURES A. Start by asking the students to reflect on what they know about the water cycle. Specifically, try to focus on the cycle part and what that means in the case of the water cycle. Also take time to explain that water is not evenly distributed among the different reservoirs within the water cycle. You can use Student Sheet Page 1 as a guide for the students. MATERIALS Each team of students will need the following: B. Divide the students in groups of five in order to play a game cycle reservoir: ocean, atmosphere, icecaps and 1. Assign each student to one of the water glaciers, groundwater, reservoir bowls and rivers, streams and 2. Place or have the students place the following number of tokens into each of the lakes bowls: 1 set of playing cards a. Atmosphere = 3 b. Glaciers and Icecaps = 20 (made from following 26 c. Rivers, Streams and Lakes = 8 d. Groundwater = 10 e. Ocean = All remaining (about 150) 3. Point out to the students that the number of tokens in each bowl represents the relative amount of water in that reservoir 4. Have the students distribute the cards so Teacher Sheets printed front and back, laminated, and cut out) 200 toothpicks, pieces of macaroni, or other tokens that each student gets all of the cards for Each student will need the their assigned reservoir. following: 5. Tell the students that each card represents One copy of Student a different process in the water cycle and destination for water in the water cycle Sheets Starting with the ocean student, each player in turn draws a card from his/her stack and moves one token from his/her bowl to the appropriate bowl at the instructions of the card. For example, if the player who has the bowl labeled Ocean draws a card that says evaporation into the atmosphere, the player will move one token from the bowl labeled Oceans to the bowl labeled Atmosphere. If the drawn card is stay then the player will not move any tokens from the bowl until it is his or her next turn. 7. As the players move the tokens, they should draw arrows between the reservoirs on their Student Sheet 2 diagram. A different color can be used for each process in the water cycle. If a process occurs more than once, the students should draw a new arrow between reservoirs each time the process occurs. No arrow is drawn if the water molecule stays in place during that turn. 8. The game may continue until all 15 cards are drawn from each stack or for as long as desired. C. At the end of the game, lead a discussion with the students about what they observed by playing this game. 5 plastic bowls, each labeled with one water

4 GUIDING QUESTIONS What type of matter is shared in the water cycle? What represented the water in the water cycle game that you played? What types of energy make the water cycle go? What represented the changes in energy that are part of the water cycle? What represented the reservoirs in the water cycle game? How was the amount of water in each of the Earth s reservoirs shown? How has the earth managed to survive using the same water for billions of years without running out? What did the arrows that you drew between the reservoirs on your diagram show? Based on the water cycle game that you played, what are some of the subsystems of the water cycle? Which types of cards say stay the most? What does this suggest about those reservoirs? EVALUATION Using Student Sheet 3, have the students list all of the things that they noticed about the movement of water between reservoirs of the water cycle. Extension: Assign each student to research and identify one way that human beings modify the water cycle either globally or in their local area. This can include such things as removing water from the ground through pumping, removing water from rivers for irrigation, building dams, acid rain, cloud seeding to increase rain, water pollution, global warming or other activities. Have them describe what reservoirs and which processes in their water cycle diagram that they drew would be affected by their activity and why.

5 STUDENT SHEET 1 Water Reservoirs on Earth

6 STUDENT SHEET 2

7 STUDENT SHEET 3

8 TEACHER SHEET 1

9 TEACHER SHEET 2

10 TEACHER SHEET 3

11 TEACHER SHEET 4

12 TEACHER SHEET 5

13 TEACHER SHEET 6

14 TEACHER SHEET 7

15 TEACHER SHEET 8

16 TEACHER SHEET 9

17 TEACHER SHEET 10

18 TEACHER SHEET 11

19 TEACHER SHEET 12

20 TEACHER SHEET 13

21 TEACHER SHEET 14

22 TEACHER SHEET 15

23 TEACHER SHEET 16

24 TEACHER SHEET 17

25 TEACHER SHEET 18

26 TEACHER SHEET 19

27 TEACHER SHEET 20

28 TEACHER SHEET 21

29 TEACHER SHEET 22

30 TEACHER SHEET 23

31 TEACHER SHEET 24

32 TEACHER SHEET 25

33 TEACHER SHEET 26

34 REFERENCES Black, P. E Watershed Hydrology, Second Edition. Ann Arbor Press, Chelsea, MI. 449pp. Schlesinger, W. H Biogeochemistry: An Analysis of Global Change, Second Edition. Academic Press, San Diego, CA. 588pp. U.S. Geological Survey Groundwater Atlas of the United States: Oklahoma, Texas. U.S.G.S Publication HA 730-E. Wetzel, R. G Limnology, Second Edition. Saunders College Publishing, Orlando, FL. 857pp.