1. Water Cycle Stories - Logistics

Time
1-2 hours depending on the students’ previous exposure to the phases of matter and the water cycle

Grouping
individual

Materials
For water cycle discussion:

• Glass of ice water to start the discussion
• Copies of Water Cycle Stories handout
• Overhead projector (or draw a copy of the image on the board)
• Overhead transparency of Water Cycle diagram
• Dice

For optional mini-investigation each student needs:

• Ziplock bag
• 1 ice cube
• 1 sample cup (the little paper cups ketchup is sometimes served in)
• several scales or balances for students to weigh their bag
• tape
• sunny window or sunny exterior wall

Setting
Classroom

Magic School Bus: at the Waterworks

While I was reading The Magic School Bus,they went inside a cloud. Because this is not a field trip, there should be no driving into clouds :). But in Inside a Hurricane, They make a water cycle experiment.

Materials:    Oven mitten,Kettle,Ice,Strainer,Water

Experiment:

1. Put water in kettle.
2. Turn on the stove.
3. As the steam comes up, put ice in strainer.
4. Open top of kettle.

Watch as the water moves around.                                                                    

1. Water Cycle Stories - Background

Teacher Background
The water cycle is at the center of many scientific topics, from watersheds (like this unit) to weather patterns to ice ages. The main idea is that almost all the water that exists on Earth today was there since the planet formed 4.6 billion years ago. However, water molecules do not stay in one place for long, at least not on a geologic time scale. The sun drives a continual process of evaporation, condensation, freezing, and melting that allows any given water molecule to travel from location to location on Earth. Thus the water cycle is the journey that water takes through its various phases (or states) – solid ice, liquid water, and gaseous water vapor – as it travels through Earth’s systems.

Water can exist in 4 phases or states – solid, liquid, gas and plasma – although plasma has little relevance to most everyday events including the water cycle. The molecules of a solid are tightly packed and bonded together so that the substance retains its shape. The molecules of a liquid are closely packed but can move relative to each other so that the substance flows. The molecules of a gas are independent of each other and move about freely in 3 dimensions. The transition from one phase to another is governed by temperature and pressure. As temperature increases and pressure decreases, a solid substance will generally transition to a liquid (it melts) and then from a liquid to a gas (it evaporates). As temperature decreases and pressure increases, a gas will generally transition to a liquid (it condenses) and then from a liquid to a solid (it freezes). It is possible for substances to transition straight from a solid to a gas in a process called sublimation. For instance, snow sometimes sublimates without turning to liquid water first. Similarly, dry ice sublimates straight to carbon dioxide gas.

With respect to the water cycle, water as a gas may travel huge distances across oceans and continents before it condenses and turns to rain or snow. Water as a liquid will flow across the Earth’s surface and percolate into the ground. Thus, water travels a lot as it undergoes phase changes. Most of this is governed by temperature as the result of the sun’s energy and less by pressure. One can therefore think of the water cycle as powered by the sun.

The water cycle is illustrated below. There are 6 major storage locations for water:

• Surface water (lakes, rivers, reservoirs, oceans, etc.) - The vast majority of Earth’s water, 97% of it, is stored in oceans.
• Atmosphere (clouds, fog, humidity, etc.)
• Precipitation (rain, snow, sleet, hail, and ice) – Water stored as precipitation in the form of snow is critical to the state of California since most Californians depend on snowmelt to provide them with fresh water throughout the dry summer months.
• Glaciers – These giant, slowly moving ice sheets form from snow that compacts and recrystalizes over time to form large ice crystals. Glaciers are more important than many realize. Approximately 75% of the Earth’s fresh water is stored as glaciers, primarily around the polar ice caps.
• Groundwater
• Living organisms – Our bodies are 50-70% water!

From each of these storage locations, water has ways to travel to other locations. Water may:

• Evaporate –from surface water into the atmosphere
• Condense – from the atmosphere into precipitation
• Melt – from precipitation as snow to surface water or from glaciers to surface water
• Freeze – from precipitation as snow to glaciers
• Percolate – from surface water to groundwater and back again
• Transpire – from living organisms to the atmosphere
• Drink – from surface water (or sometimes groundwater) to living organisms
• Excrete – from living organisms to surface or groundwater

 

Student Prerequisites
Previous exposure to the phases of matter and the water cycle is helpful but not necessary. If students have not learned about these topics in the past, then on day 1, do the phases of matter mini-investigation and discuss the locations where water is stored. On day 2, analyze the results of the mini-investigation and discuss the transitions between locations in the water cycle.

 

 

1. Water Cycle Stories - Getting Ready

Getting Ready
For water cycle discussion:

1. Make copies of the Water Cycle Stories handout for each student.
2. Make overhead copy of the Water Cycle diagram.
3. Fill a clear glass with ice water and leave it on a coaster at the front of the room.
4. Get dice.

For optional mini-exploration:
Collect materials: Ziplock bags, ice cubes, tape, scales.

1. Water Cycle Stories - Lesson Plan

Lesson Plan
Optional mini-exploration:

1. Ask students what they predict will happen if I zip an ice cube in a Ziplock bag. In particular, what will happen to the weight of the bag as the ice turns to water and then turns to water vapor? Many students will think that the bag will weigh less after the water melts and some of it turns to water vapor.
2. Have students write down their predictions on a lab notebook. I had my students draw a series of pictures with captions showing the plastic bag now, in 2 hours, and tomorrow.
3. Try the experiment. Pass out bags, sample cups and ice cubes. Place the ice cube in the sample cup and then place the whole thing in the Ziplock bag. Make sure there is a good quantity of air in the bags before sealing them so that any condensation that accumulates may be observed. Make sure the bags are tightly sealed.
4. Have each student measure the mass of their bag and record that measurement in their lab notebook before taping the bag to the window or wall. Make sure the sample cup is right-side-up with the ice inside. If you wish, you can use any remaining class time to introduce the locations on Earth where water is stored (Step #10 of the Water Cycle discussion lesson plan below).
5. The following day, make some observations of the bags before taking them down. The ice should have melted and some condensation will have appeared on the sides of the bag and run down the sides of the bag to collect below the cup.
6. Take the bags down and remove any tape. Measure the mass of the bags and compare the measurement to the previous day.
7. Ask the students: Did anything surprise you?  Did everything happen according to your predictions? Flow directly into the Water Cycle discussion below.

Water Cycle discussion and storytelling:

1. Begin by setting the glass of ice water on the table at the front of the room. Ask the students to make observations of the glass. What is happening to the ice? What is happening on the outside of the glass? Why are these things happening?
2. Allow these initial observations to transition into a discussion of phase change. Ask students what they know about how and why water can transition from ice to liquid water to water vapor. Students may or may not know about how increasing temperature translates into molecular movement – that solids are solids because the molecules are locked in place and can only vibrate while in gases the molecules are energetic and move freely.
3. Invite 9 volunteers to come to the front of the room. Each student represents one molecule of water. Have them stand closely together in 3 rows of 3 students and interlock arms. They now represent water in its solid form – ice. Tell them that they are cold. They may shiver and vibrate a little but should remain bound together.
4. Now tell them you have placed the glass of water in a sunny window and the molecules of water in the ice cube have begun to get energized. They can now move around but should stay together in a cluster. They have melted and become liquid water. They should naturally unlink their arms and perhaps might join hands. Allow them to “flow” around the room and use that to illustrate the fluid motion of liquids. If you wish, you can introduce the idea of hydrogen bonding and surface tension as the reasons that liquids stay together.
5. Now tell them that the sun has become really warm and they are very very excited and can move about freely. The cluster of 9 will soon disperse about the room, probably colliding with desks, other students and the walls of the room. You may need to have the water molecules “freeze” temporarily in order for your explanation to be heard by the students. They have evaporated and now represent water as a gas – water vapor or steam.
6. Finally, tell them that the sun has set and it is beginning to become cold. When they collide with another water molecule, they should “stick together for warmth”. Soon all the water molecules will form a liquid again. They have now condensed back onto a liquid. You may take things all the way back to the beginning again and tell the molecules to freeze solid by linking arms once again.
7. Thank your water molecules and have them return to their seats. Review the process of phase change that they observed, noting the way that temperature changed the behavior of the molecules.
8. Ask the students where the energy that caused the temperature change came from. (The sun.)
9. Point out that this process – the phase changes of water powered by the sun – is what drives weather patterns, the movement of water around the globe, and the resulting erosion that shapes our landscape. Also point out that while water changes state and moves around, it is rarely created or destroyed. The water that exists on the planet today is OLD. At one time, the water molecules they drank this morning were once in the oceans when the Earth first formed and perhaps even were drunk by a dinosaur and later peed out again. If you did the mini-investigation, draw an analogy between the mini-investigation and the water cycle. The quantity of water in the bag stayed the same just like the quantity of water on the planet has stayed the same since the planet was formed. Just like in the bags, the water on the planet continually changes state and moves around from place to place.
10. Give students the handout and turn on the overhead projector with the water cycle drawing.
11. Invite students to name places on or around the planet where water can be found in any of its forms. As students provide one of the 6 major locations where water is stored (surface water, atmosphere, precipitation, glaciers, groundwater, living organisms) fill in that area on the water cycle transparency and have students copy our labels onto their own diagrams. Discuss the importance of each of the storage areas as you label it (see Teacher Background).
12. Next, ask students how they think water moves from place to place. As they point out each part of the water cycle (evaporate, condense, melt, freeze, percolate, transpire, drink, excrete) introduce an arrow and a label for the diagram.
13. Once the diagrams are completed, read or tell the students a story of a water molecule that makes a journey through the water cycle. An example of a story that follows a drop of water may be found on the USGS site. There is also a Magic School Bus episode by Pat Relf where Ms. Frizzle’s famous class takes a journey through the water cycle.
14. Tell the students that they now have the job of telling the story of a water molecule that makes its own journey through the water cycle. Notice that each of the locations where water is stored has a number. Students will roll a dice to figure out where each water molecule will begin and end its journey. On its way, the water molecule must travel through at least 4 different locations including a living organism.
15. Allow students time to outline their stories during class and check that each student has a reasonable story outline. The story itself can be completed as homework.

1. Water Cycle Stories - Assessments

Assessment

1. Completed stories can be graded for comprehension.
2. If you choose to have students share their stories, have students imagine 2 more steps of the water molecule’s journey.
3. If you did the mini-investigation, have students diagram the water molecules at different stages of the experiment.

Going Further

1. Using the stories that students write as a rough draft, help students edit and revise their story and turn the stories into illustrated children’s books. These books can be shared with elementary school students.
2. The University Corporation for Atmospheric Research website has fabulous information and resources for teachers. One of many excellent activities shows you how to build a fabulous model of the water cycle with a lamp, a clear plastic box, some clay and some ice. This model may be used to illustrate and visualize the convection currents that cause common weather patterns.

1. Water Cycle Stories - Sources and Standards

Sources
The mini-investigation was inspired by the Mini Water Cycle lesson in Water Precious Water by the AIMS Education Foundation.

Using students to model the behavior of molecules in a solid, liquid and gas was inspired by a lesson I observed by Michael Geluardi, a science teacher and friend at Piedmont High School in Oakland, CA.

The story writing part of this lesson was inspired by Activity 3 from the SEPUP unit Groundwater Contamination: Trouble in Fruitvale.

A great resource for additional information about the water cycle may be found on the USGS website.

Standards
Grade 6
Shaping Earth’s Surface
Energy in the Earth System
4. Many phenomena on Earth’s surface are affected by the transfer of energy through radiation and convection currents. As a basis for understanding this concept:
a. Students know the sun is the major source of energy for phenomena on Earth’s surface; it powers winds, ocean currents, and the water cycle.
d. Students know convection currents distribute heat in the atmosphere and oceans.
e. Students know differences in pressure, heat, air movement, and humidity result in changes of weather.

Grade 8
Structure of Matter
3. Each of the more than 100 elements of matter has distinct properties and a distinct atomic structure. All forms of matter are composed of one or more of the elements. As a basis for understanding this concept:
e. Students know that in solids the atoms are closely locked in position and can only vibrate; in liquids the atoms and molecules are more loosely connected and can collide with and move past one another; and in gases the atoms and molecules are free to move independently, colliding frequently.

Reactions
5. Chemical reactions are processes in which atoms are rearranged into different combinations of molecules. As a basis for understanding this concept:
d. Students know physical processes include freezing and boiling, in which a material changes form with no chemical reaction.

Chemistry of Living Systems (Life Sciences)
6. Principles of chemistry underlie the functioning of biological systems. As a basis for understanding this concept:
c. Students know that living organisms have many different kinds of molecules, including small ones, such as water and salt, and very large ones, such as carbohydrates, fats, proteins, and DNA.

2. Watersheds and Wetlands - Logistics

Time
70-90 minutes - approximately 20-30 minutes per wetland for construction, the activity, discussion and clean up. I recommend doing the first activity to introduce the idea of a watershed on one day then do both wetland activities on the following day. If you are short on time or if students are already familiar with the concept of a watershed, then you can add wetlands right away.

Grouping
Teams of 3 students that later pair up into groups of 6

Materials
Each team of 3 students needs:

• 1 plastic shoebox-sized container (great for organizing supply closets later on!)
• 1 kitchen sponge cut into 4 rectangular pieces (the yellow sponges with the green scrubbing material are cool because kids can observe a color change in the yellow “soil” portion of the sponge while the green material simulates plants living in the wetlands)
• 1 water spray bottle (available at most hardware stores near the cleaning supplies or at plant nurseries for watering and misting plants)
• a multi-color assortment of water-based markers

The teacher needs:

• a stack of white cardstock paper (each team will use 3 sheets)
• 1 packet of colored drink mix like Koolaid or Hawaiian Punch
• 1 spoon
• optional - map or satellite image of the school and neighboring areas showing the watershed

Everyone needs:

• a copy of the Watershed and Wetlands Questions
• a sink to clean sponges and dump dirty water
• a trash can

Setting
classroom

2. Watersheds and Wetlands - Background

Teacher Background
The concept of the watershed forms the foundation of much environmental science. Formally, a “watershed” is the area of land that water flows over and through on its way to a larger body of water like a creek, river, lake, or bay. Practically, this means that a watershed is all the land that drains into a specific body of water. Every house, school, and neighborhood is part of a watershed. Studying ones own watershed allows students to apply scientific knowledge to their neighborhood and community and are easy ways for students to make connections between their actions (pollution, water conservation, habitat restoration, etc.) and the quality of the environment they live in.

Watersheds may be as large as several states (the Mississippi River watershed for example) or as small as a few city blocks. For instance, the San Francisco Bay watershed covers the entire western slope of the Sierra Nevada Mountains, the Central Valley of California, the Sacramento River Delta, and the many smaller creek systems that surround the San Francisco Bay itself. This area of land is approximately 40% of the entire state of California! One could also refer to the Codornices Creek watershed in Berkeley that my school is near. It’s area encompasses a narrow strip of land 5 blocks wide and 3 miles long between the San Francisco Bay and the Berkeley hills. Both are equally valid watersheds to discuss since students can see their personal connection both to the Bay and to the neighborhood they live and go to school in.

A watershed begins in the tallest mountain areas where water falls as rain or snow. This water then trickles into rivulets, rivulets merge into creeks, and creeks merge into rivers on the water’s way downhill. Eventually, these streams of water reach the larger body of water under study – a bay, a river, a lake, a creek. Much of this water will also seep into the ground as groundwater and may travel much more slowly through the soil and rock and perhaps underground aquifers to reach a body of water. Any land a water drop has traveled over or through to get to the body of water being studied belongs to that watershed. All this movement of water is part of the larger water cycle (see the Water Cycle Stories Lesson).

I found that my students had a difficult time understanding that a watershed meant land and did not just include the creeks, rivers, lakes and bays. Pointing out that a watershed is usually bordered by ridges helps. Using a 3-D map to illustrate separate valleys that have separate watersheds also helps.

At the edges of a watershed, particularly those with little human development, one will find wetlands. Broadly defined, “wetlands” are transitional areas between land and water habitats. More specifically, the wetlands are characterized by:

• lots of water - the water table is at the surface or close to it most of the time
• soil that is wet much of the time (although some wetlands are actually dry for more of the year than they are wet)
• specialized plants that are adapted to live in wet soils with lots of groundwater

The many types of wetlands include marshes, swamps, bogs, meadows, mud flats, and other habitats where land and water meet.

In the not so distant past, up until even the 1970’s, wetlands were often considered to be wasted space. The marshy land at the edges of bays seemed wasted on the weedy plants that grew there and seemed like perfect, flat strips of land that could be filled in with soil and concrete to build desirable waterfront housing, office, and industrial space. In a span of 150 years, the San Francisco Bay watershed lost 90% of its wetlands. And only now are we realizing their worth and importance to a healthy ecosystem.

Wetlands serve many essential roles in the environment. They are critical habitat for many specialized plants and animals that survive nowhere else. The plants that live in a wetland act as a filter to soak up pollution that runs off upstream. In fact, several communities such as Arcata, CA and Phoenix, AZ use wetlands as part of their urban water treatment facilities instead of the harsh chemical treatments that must otherwise occur. Wetlands also serve as a reservoir to even out fluctuating water levels, soaking up excess water during a wet times and releasing stored water during dry times. Finally, as the nation learned in the Hurricane Katrina disaster, wetlands can serve as a buffer against natural disasters such as hurricanes (for more on this, see Katrina Case Study lesson).

Student Prerequisites
An understanding of the water cycle (see Water Cycle Stories lesson).

2. Watersheds and Wetlands - Getting Ready

Getting Ready

1. Set out cardstock paper.
2. Fill water bottles (or kids can do this).
3. Collect the remaining materials needed for each group of 3 students (4 pieces of kitchen sponge, 1 water spray bottle, a multi-color assortment of water-based markers) into their plastic bin and set out near cardstock paper.
4. Open the packet of drink mix and set aside with the spoon in a place students won’t readily access (or they’ll try to eat it!).

2. Watersheds and Wetlands - Lesson Plan

Lesson Plan
Part 1 – Building a watershed

1. Tell students to imagine that it is raining. Ask the students: “Where does raindrop go after it hits the school building? Where does it go from there? Where does it end up?” They should be able to trace it to a gutter. You may need to prompt them towards naming a nearby creek and onwards to a river, bay or ocean. You may want to draw a diagram of this path on the board.
2. Discuss the idea of a watershed. It includes all the land that water flows over and through to get to a larger body of water. Help students imagine what this means in terms of a raindrop that falls in different places in your watershed. Use a map if you want. It is not important that all the kids completely understand the idea right now. The activity that follows should help consolidate the idea for kids that aren’t getting it right away.
3. Tell the students that they will be building models of watersheds and observing what happens to their models when it “rains”. Briefly demonstrate what they will be doing to make their watershed (see steps 5-8 below) so they can see a nearly finished product before setting the kids loose.
4. Split the class into groups of 3 and have 1 member of each group collect 3 sheets of cardstock and 1 watershed tub. The rest of the group should clear everything off the tables except for a pencil for each student (they may get wet).
5. Crumple the sheet of cardstock into a ball then slowly flatten it out again. You should have a piece of paper with many valleys and ridges. Pick one end to be the top; this end will have tall mountains. The other end will be near a bay.
6. First, add water to your watershed – creeks that run into rivers, lakes, ponds. Make students think about where to put these rivers. Will they be at the tops of ridges or in the valleys? Where might lakes form?
7. Next add natural areas – animals, trees, plants, rocks, sandy banks. Add urban and agricultural areas – houses, cars, schools, farms, gardens, factories, roads, cars. Make students think about where to put various things. Where would you find forests? Where would you find meadows? Where would animals want to live? Where might it be very rocky? Where would people want to build houses? How would they get to their houses? Where would they work and go to school? Where would their food come from? Would you want to build a farm at the top of a mountain? Allow 5-10 minutes for students to finish their watersheds. They should be very colorful at this point.
8. Carefully fit the watershed into the plastic bin so that the mountainside is propped up on the narrow end of the bin (the mountain end) and the land slopes gradually towards the far end of the bin (the bay end), leaving a 2-3 inch gap between the end of the paper and the bay end. Wedge the paper snugly in place leaving as little gap as possible between the sides of the bin and the paper.
9. Take one of the markers and prop the mountain end of the bin up a little. This is to make sure that a bay forms on the bay end and does not run back under the land.
10. The 3 students should take turns spraying the paper using the fine mist setting. Spray for 3-5 minutes until there is a decent sized puddle in the bay end.
11. Give students the Watershed and Wetlands Questions handout and give students a few minutes to answer the first set of questions. The questions do not have to be used during class. You could use the questions to being a class discussion or use them as a homework assessment. I found that the discussions following each activity were more directed and targeted after students had thought about the activity individually first. I still collected the questions as an assessment.
12. When students have finished writing their answers, begin a discussion of how this model represents a watershed and how different things affect the watershed. If you still have the diagram of your watershed on the board, you could add these ideas to your diagram. Now is the time to really consolidate the idea of a watershed. Some questions you may want to consider include:
13. What path did the rain take through your watershed?
14. What effect do natural areas have on the watershed? Urban areas? Agricultural areas?
15. What is “runoff”? Is runoff different in natural versus urban versus agricultural areas? It is important to distinguish erosion from urban runoff. Also, it may be interesting to think about differences in urban versus agricultural runoff.
16. What affect does runoff have on the bay?
17. What is a watershed? How is this model similar to a real watershed? How is it different?

Part 2 – Adding Wetlands

1. Tell students that they will now build another watershed. This time, we will compare watersheds with wetlands to those without. Open a discussion of what students think wetlands are. Have they ever seen one? What does it look like? What kinds of plants and animals live there? If they don’t know the term wetland, they will likely have heard of a marsh and can bring up a good mental picture.
2. Pair teams up with one another. One team will have a wetland represented by sponges at the border between the land and the bay; the other will do the activity exactly as before (in the third rendition, they will switch roles so that everyone has a wetland once).
3. Clean up the materials and allow groups to create a new watershed with a new sheet of cardstock paper. It should not take as much time this time nor is it necessary for the watersheds to be as elaborate.
4. Set up the bins as before, however, one team should add a tightly packed row of damp sponges to the border between the land and the bay. THE SPONGES MUST BE DAMP. They should not be sopping wet, nor should they be wrung out as much as possible. They should be somewhere in between so that some water could still be wrung out if you tried.
5. Place the watershed with wetlands directly beside the watershed without wetlands and prop up the mountain end with a marker.
6. Allow it to rain an equal amount on each watershed. The students should make an effort to squirt the 2 watersheds an equal number of times. As it rains, encourage them to notice any differences between the 2 watersheds.Stop when a decent sized bay had built up – about 3 minutes.
7. Give students a few minutes to answer the second set of questions. When students have finished writing their answers, begin a discussion of what the role of watersheds might be. Some questions you may want to consider include:
8. Were there any differences in how quickly each bay filled? What does that mean about what wetlands do in times of heavy rain? Introduce the idea of wetlands as sponges during wet times and reservoirs during dry times to even out the flow of water.
9. What happened to the color of the bottoms of the sponges? What does this represent? Introduce the idea of wetlands as filters for pollution.

Part 3 – Toxic Waste!

1. Have students hypothesize what might happen to a watershed if a truck carrying pesticides crashed along a highway near a creek. What parts of the watershed might be affected?
2. Students will now have a chance to test their ideas on their models. As before, there will be one team with a wetland and one without, however they should switch roles. A spoonful of pesticide will be added to each watershed before it rains.
3. Clean up the materials and allow groups to create a new watershed with a new sheet of cardstock paper. Set up the bins as before, placing the watershed with wetlands directly beside the watershed without wetlands and prop up the mountain end with a marker.
4. At this point, the teacher should go around and add a teaspoonful of drink mix to the middle of each watershed.
5. Allow it to rain an equal amount on each watershed. Notice any differences between the 2 watersheds. Stop when a decent sized bay had built up – about 3 minutes.
6. Give students a few minutes to answer the final set of questions. When students have finished writing their answers, begin a discussion about the differences between non-point source pollution (runoff) and a pesticide spill. This activity should clearly illustrate how a single event in one location can affect a very large area and affects all downstream water users including wildlife in the marsh and the bay. Students will observe that while a wetland can soak up some pollution, some will also leak through into the bay. Can it be cleaned up once it gets into the water? Emphasize that although a waste spill is far more dramatic, urban non-point source pollution accounts for the vast majority of the pollution in most watersheds.
7. Given what we’ve discovered about watersheds and wetlands, what can we do to help them thrive? Have students brainstorm ideas.
8. Clean up.

2. Watersheds and Wetlands - Assessments

Assessment

1. The Watershed and Wetlands Questions can be used as an assessment tool.
2. Have students create a flyer that encourages other students to do something to help their watershed. Post them around the classroom or around school.

Going Further

1. Have students research the use of constructed wetlands as an alternative wastewater treatment option and present their findings on posters. The Water Resources Research Center at the University of Arizona offers some excellent information as does the Arcata Marsh and Wildlife Sanctuary.
2. Go on a field trip to a wetland! Even better, do some restoration work there. For one idea, see the Save the Bay Field trip.
3. Delve into a case study of how wetlands form, how they are destroyed, and what the effects of wetland destruction are. Research your local area or investigate the wetlands of Louisiana and their role in the Hurricane Katrina disaster. See the Katrina Case Study lesson.

2. Watersheds and Wetlands - Sources and Standards

Sources
The idea for this lesson came from the “Watershed in your hand” lesson from the Watershed Project’s Kids in Creeks curriculum and from the “Wetlands in a pan” lesson from Save the Bay’s Watershed curriculum. Save the Bay’s versions of these lessons are available below as pdf documents.

The following sites provide excellent scientific background information about wetlands and watersheds.

• The National Wetlands Research Center by USGS
• Science in your Watershed  also by USGS
• An article on Wetland Environments by James Aber
• Save the Bay recently launched its fantastic new Bay Classroom

Although out of print, the USGS Water Resources Outreach Program has produced 9 fabulous posters with beautiful, colorful depictions of watersheds, wetlands, waste water treatment, water quality and more. Each poster has activities on the back with you can view online. 

Standards
Grade 6

2. Topography is reshaped by the weathering of rock and soil and by the transportation and deposition of sediment. As a basis for understanding this concept:

a. Students know water running downhill is the dominant process in shaping the landscape, including California’s landscape.

b. Students know rivers and streams are dynamic systems that erode, transport sediment, change course, and flood their banks in natural and recurring patterns.

7. Scientific progress is made by asking meaningful questions and conducting careful investigations. As a basis for understanding this concept and addressing the content in the other three strands, students should develop their own questions and perform investigations. Students will:

a. Develop a hypothesis.

f. Read a topographic map and a geologic map for evidence provided on the maps and construct and interpret a simple scale map.

Attachment	Size
Watershed_in_Your_Hands.pdf	82.38 KB
Wetlands_in_a_Pan.pdf	151.85 KB

3. Katrina Case Study - Logistics

Time
45-55 minutes

Grouping
individual

Materials

1. Computer with internet access, preferably with a projector for the whole class to watch at once, although multiple computers that groups of 4 students can share will also work.
2. Watering can to simulate rain
3. Pitcher, watering can, or container you can pour muddy water from
4. Masking tape
5. Clear plastic tray or cup with 3-4 holes punched in the bottom (the clear lids of take-out salad containers are perfect although clear plastic cups will do as well.)
6. Square of cheesecloth large enough to cover the bottom of the tray or cup
7. Good loamy soil with a mix of sand, silt, clay and organic matter to represent marsh soil (garden soil is fine although you can always collect soil from a marsh to study and observe the real thing)
8. Hand trowel
9. Large basin that your tray can sit in (a large plastic dishwashing basin works well)

Setting
classroom

3. Katrina Case Study - Background

Teacher Background
The recent hurricane in Louisiana is an ideal opportunity to connect what students are learning about wetlands to real world situations. Students with some background knowledge of what wetlands are and the important environmental roles they play can now apply these concepts to events in the Mississippi River delta.

In their natural state, wetlands are caught in the balance between subsidence and flooding. Subsidence in the most general sense is the sinking of soil relative to sea level. Subsidence is a natural part of wetlands due to soil compaction – air pockets in the soil collapse under the weight of the soil above.  In addition, some soil is eroded away by water and wind. Humans contribute to subsidence by extracting oil and natural gas (the soil above collapses when the oil below is removed). Although wetlands are sinking little by little, regular flooding brings in new sediment to rebuild the lost soil and maintain the soil levels in the wetlands. As the plant life in wetlands die, the decaying organic matter also contributes to the overall building of wetland soils. In its natural state, these two forces – soil loss through subsidence and soil building through flooding – are in balance, or in fact, wetlands grow over time as new sediment pours in from rivers and streams.

However, human developments strongly encourage the building of levees, dams, and canals to control flooding and improve water traffic. This prevents the soil building part of the equation, leaving an overall loss of soil year after year. The sediments in the canals shoot out to sea rather than rebuilding wetland soils. Wetlands shrink and eventually disappear. Land sinks. This is why much of New Orleans is below sea level. In fact, many other urbanized delta regions such as the Sacramento River Delta are experiencing the same subsidence problems.

Wetlands provide a natural sponge to soak up flood waters and act as a speed bump, slowing down hurricanes and blocking storm surges. Without much of the wetlands around Louisiana gone and with large areas of developed land below sea level due to subsidence, the effects of Hurricane Katrina were amplified upon the city of New Orleans.

So what can we do? First and foremost, we can educate ourselves and others about the science behind subsidence in order to understand the problem and not make the same mistakes in the future. Secondly, we can protect the few wetlands that remain as stewards of the environment. Finally, we can engage ourselves in rebuilding wetlands through habitat restoration efforts, many of which welcome teachers and their students to participate.

Student Prerequisites
Students should be familiar with what wetlands are and the important functions they serve in an environment. It is helpful if they have played with soil and looked at the components in soil (see Soil Analysis lesson) although it is not essential.

3. Katrina Case Study - Getting Ready

Getting Ready
For Subsidence Demonstration

1. Make 3-4 hole-punch sized holes in the bottom of the cup or tray.
2. Cut a square of cheesecloth to cover the holes.
3. Add a 4 inch layer of soil.
4. Put the tray inside the larger basin to catch any runoff. Water the soil until water just begins to drip out the holes in the bottom.
5. Use the hand trowel to fluff the soil slightly and then smooth the top surface so that it is mostly even.
6. Use a piece of masking tape to mark the top of the soil. Match the bottom edge of the tape to the top of the soil.
7. Fill the watering can about halfway with water.
8. In the pitcher or second watering can, create a mixture of soil and water - approximately 1 cup soil for 2 parts water. Stir.

For Video

1. Open PBS’s NOW website on the computer you plan to use. Click on “Watch the Video”.
2. Preview the video now or pause it to be ready to go when the kids arrive.

3. Katrina Case Study - Lesson Plan

Lesson Plan
Subsidence Demonstration

1. Quickly review wetlands with the students. What are wetlands? Why are they important?
2. Next, tell students that you are going to show them a model of what happens to soil in wetlands over time. Bring out the tray with soil, the watering can and the pitcher of muddy water. Show the students what is in the tray. In particular, point out the level of the soil and the masking tape that marks the surface.
3. Explain to students that the soil in wetlands is a mixture of different sized sediments (clay, silt, sand), organic material, and water. In the soil there are air pockets. As soil gets exposed to rain, wind, and animals walking over it, it compacts. At this point, alternately use the hand trowel to pat down the soil in the tray and use the watering can of water to simulate rain. The level of the soil should subside up to an inch.
4. Ask the students what they notice. What happened to the level of the soil? Why? Ask students to help define compaction and subsidence given what they observed.
5. This process is always happening. Over time, the wetlands would sink completely underwater and disappear. Therefore, subsidence must be balanced by some other constructive force or the wetlands wouldn’t exist. Describe how rivers pick up sediments on their way down from the mountains in the watershed. Stir up the mud in the pitcher. These sediments are carried downstream by the water until they slow down as they pass through the wetlands. Pour some of the muddy water on the soil. Every so often, the river will flood, causing even more sediment to flow out onto the land. Mix up the pitcher thoroughly and pour a large quanity of the muddy water onto the wetlands, allowing a small layer of water to cover the surface and slowly drain out from the drain holes below.
6. Again, ask the students what they notice. What happened to the level of the soil? Why? Ensure that students see the balance between subsidence and sedimentation as natural events that contribute to a healthy wetland. Encourage students to predict what would happen if there was more sedimentation than subsidence or what would happen if flooding was prevented altogether.

Video

1. Tell students they will watch a video about Hurricane Katrina. If you have time, students may share some of the things they know about the disaster from the media.
2. Show the PBS Katrina video.

Discussion

1. Begin a discussion of the video focusing on why there are fewer wetlands and how that increased the severity of the damage caused by Katrina. Some questions you may want to consider include:
   • Before the Europeans came to Louisiana, was there more subsidence or more sedimentation? How do you know?
   • When New Orleans was first settled, was it above or below sea level?
   • Why did settlers build the levees? What effect did this have on the wetlands?
   • What else has been built by humans? What impact do these other structures have on the wetlands?
   • How much of the original wetlands remain? How quickly are wetlands being lost?
   • How do wetlands reduce the impact of hurricanes?
2. Allow the discussion of wetlands gradually transform into why wetlands are important and what we can do to save them. Some questions you may want to consider include:
   • Did people from the past not care about wetlands? (No, protecting their homes from flooding was more important to them and they didn’t know that wetlands were valuable.)
   • Should we care about wetlands loss? Why?
   • Do you think our politicians care about wetlands loss? Should they?
   • Do you think your parents know about wetlands loss? How can we teach them?
   • Should we protect the wetlands that are left? How should we do that?
   • Should we try to build new wetlands? Where?
   • What does it mean to be a steward of your environment?
3. End class on a positive note by brainstorming ways students can help protect, save or restore wetlands.

3. Katrina Case Study - Assessments

Assessment

1. Have students teach a family member about the connection between levee building, wetlands loss, and Hurricane Katrina. Have the family member write a short paragraph about what they learned from the student.
2. Ask students to locate a wetland in their local area and find out what plants and animals are there, if they can visit it, and if there are any on-going habitat restoration efforts there.
3. National Geographic ran an article in October 2004, 1 year before Katrina, discussing the loss of wetlands in Louisiana and the devastation that would be caused by a large hurricane. Have students read the article and make comparisons between the predictions and what actually happened a year later.

Going Further

1. NOVA and Frontline will air “Storm that Drowned a City” on November 22 at 8 pm. It promises to be an hour long investigation of the science behind Hurricane Katrina, going into far more detail than the 15 minute video highlighted here.
2. USGS has a great series of hands-on activities called the Fragile Fringe which provides extensive teacher information and resources on wetlands, their importance and their loss.
3. GET INVOLVED! The EPA has an Adopt Your Watershed campaign encouraging kids to become environmental stewards and join forces with the many groups leading cleanup and restoration efforts around the country. To adopt a creek and conduct habitat restoration activities here in the Bay Area, my students and I have worked with: 
   • Save the Bay
   • EarthTeam
   • City of Oakland Public Works Agency
   • Urban Creeks Council

3. Katrina Case Study - Sources and Standards

Sources
The subsidence demonstration was adapted from the Loss of Wetlands: Subsidence activity from the USGS Fragile Fringe series.

The Audubon Society has a great page on wetlands loss and how to protect what remains.

For additional information, see the Sources and Standards section of the Watersheds and Wetlands activity.

Standards
Grade 6
2. Topography is reshaped by the weathering of rock and soil and by the transportation and deposition of sediment. As a basis for understanding this concept:
a. Students know water running downhill is the dominant process in shaping the landscape, including California’s landscape.
b. Students know rivers and streams are dynamic systems that erode, transport sediment, change course, and flood their banks in natural and recurring patterns.
d. Students know earthquakes, volcanic eruptions, landslides, and floods change human and wildlife habitats.

4. San Francisco Bay Watershed - Logistics

Time 20-30 minutes Grouping class Materials   Physical map of California, preferably 3 dimensional (see Sources for suppliers) Removable color coding labels (available at most drug stores and office supply stores) or small Post-It Notes Optional: satellite image of the San Francisco Bay (see Sources for suppliers) Optional: map of your local watershed (see Sources for suppliers)

Setting
classroom

4. San Francisco Bay Watershed - Background

 

Teacher Background
The San Francisco Bay watershed covers 40% of the state of California. It provides drinking water for 2 out of 3 Californians and is the mainstay of the $18 billion dollar agricultural industry in this state. But it’s not just people who benefit. California is one of the biodiversity hotspots of the world, right alongside the Amazon River basin, Hawaii, and southeast Asia. There are large numbers of specialized habitats (like redwood forests) and endangered species who depend on the San Francisco Bay watershed for their survival. All Californians should know something about this critical aspect of their state.

Historically, the San Francisco Bay is relatively young. A million years ago (very recently in geologic time), a lake filled the Central Valley and drained out Monterey Bay. It was only 560,000 years ago that movement along the San Andreas Fault sealed off the passage through Monterey Bay and opened a new passage through San Francisco. Since then, due to the melting and refreezing of glaciers and ice sheets during the Ice Ages, at least 5 different San Francisco Bays have been known to exist. During an Ice Age, Earth’s water is primarily trapped in the mountains and polar regions as glaciers. The sea level drops up to 300 feet or more and beachfront property is miles offshore near the Farallon Islands. During inter-glacial periods, the glaciers melt, refill the oceans, and a Bay forms approximately where we find the Bay today.

My students had a very difficult time with the concept of the Ice Ages. Most held the mistaken belief that during the Ice Age, world temperatures plummeted suddenly (in a single lifetime or less) and the entire Bay was frozen as a gigantic skating rink. They believed the average temperatures on a typical October day to be around negative 20 degrees Fahrenheit. They knew there were animals but believed there were no plants that could possibly live in such cold temperatures. It took a lot of coaxing and evidence to convince them that this was not the case. In fact, the average temperatures during the Ice Ages were only 10-12 degrees less than they are now. While this does not sound like a big change, this is approximately equivalent to moving Canadian weather down to San Francisco.

The Gold Rush has an enormous impact on the Bay. Hydraulic mining, a mining technique in which high pressure water hoses washed away entire hillsides to reveal the gold within, washed 12 billion tons of sediment down the rivers and into the Bay. Riverbeds became shallow and caused massive flooding in the Central Valley. The Bay itself became far more shallow and is now an average of only 14 feet deep. Transportation channels must be continually dredged to permit large boats to pass. Moreover, miners used the deadly toxin mercury to help extract gold. 12 million pounds of mercury washed downstream to mix with the sediments of the Bay.

California’s Sacramento River Delta is unusual in that it is an inverted river delta where two rivers converge and are forced through a single pass rather than a traditional river delta where a single diverges into many rivulets on its final journey to the ocean.

The soil is exceedingly rich in nutrients, which has made the delta region a rich agricultural area. However, levees built around the many delta islands have contributed towards extensive subsidence. Today, much of the delta lies below the waterline and is in danger of flooding if any of the levees should break.

The Bay itself has 4 lobes. The Delta feeds into Suisun Bay which then extends into San Pablo Bay. The Central Bay then opens out to the Pacific Ocean through the Golden Gate. The South Bay drains the areas surrounding San Jose and also exits via the Central Bay to the Pacific. In a satellite image, the Bay looks like a mermaid in profile. San Pablo Bay forms her head with Suisun Bay and the California Delta as her hair stretching towards the mountains. The Central Bay forms her body with her arms in prayer (“Please help save me!”) or others claim her arms reach out through the Golden Gate to the sea. The South Bay forms her tail.

This lesson is an excellent prelude to
field trip to the San Francisco Bay Model in Sausalito or before a trip with the Marine Science Institute on their fabulous research vessel, the SS Bownlee, where students can catch and observe the Bay’s creatures up close.

Student Prerequisites
Students should know what a watershed is (see
Watersheds and Wetlands activity) and be familiar with the water cycle (see Water Cycle Stories activity).

4. San Francisco Bay Watershed - Getting Ready

Getting Ready

1. Post maps at the front of the room.
2. Have a sheet of color labels ready.

4. San Francisco Bay Watershed - Lesson Plan

Lesson Plan

1. Have students look at the shaded relief map of California. Have a volunteer locate:
   • Their school
   • The tallest mountains, the Sierra Nevadas (Mount Whitney is the tallest mountain in the lower 48 states at 14,491 feet tall)
   • The San Francisco Bay
   • The state capital (Sacramento)
   • Los Angeles
   • The Pacific Ocean
   • Any other important landmarks they know from history and geography
2. Next lead the students through the watershed by following the journey of water through the seasons, similar to what they’ve already done in Water Cycle Stories. Focus on how water gets to the Bay and the differences in water flow through the seasons. The way I did this in my classes was a “Finish My Sentences” lecture. I walked students through the watershed, pausing and holding my hand out to invite students to fill in my silences at specific times. For instance I might begin, “Ok, we all know that water can’t run uphill, it only runs __(downhill)__. So water in California will start up high in the __(mountains)__ and make its way downhill towards the __(ocean)__. Look up here at the tops of the tall Sierra Nevada Mountains. Throughout the winter they become covered in __(snow)__. When spring comes, the snow __(melts)__, and the water runs through these __(valleys)__ as rivers.”
3. Next, have students decide whether or not a drop of rain that falls in a certain place will eventually find its way to the Bay (if it doesn’t evaporate first). Label those drops that make it to the Bay in one color and those that don’t make it in another color. For instance, have students raise their hand if the think a drop that falls in the Delta will end up in the Bay. Place a blue dot in the Delta since it will make it to the Bay. Next, ask them about a drop that falls in Los Angeles. Place a red dot there since it won’t make it to the Bay. Continue asking about various places around California until a pattern develops – any drops in or around the Central Valley will make it while any drops outside this area won’t.
4. Point out how students have just identified the San Francisco Bay Watershed. Review the definition of a watershed and highlight the borders of the watershed with your finger on the map. Stress the idea that the watershed is land, many of my students focused exclusively on the rivers and water features. If you choose to discuss the importance of the watershed to people, the economy, and wildlife, this is a good time to do so.
5. Show students how their hands can be turned into a model of the watershed that they can take with them wherever they go. Have students cup their hands together. Their hands should form a bowl with the pinkie-side of the palms touching and their fingers cupped outward and upward. This bowl represents the watershed. The tallest points, the fingertips, are the Sierra Nevada Mountains. The white ends of your fingernails are the snow-capped peaks. The left thumb represents the Siskiyou Mountains in the north. The right thumb represents the Tehachapi Mountains in the south. The heels your palms below your thumbs are the Coast Range Mountains. As the snow melts off your fingertips, the water runs along the valleys between your fingers as rivers. As they reach your palms, the Central Valley, they collect into 2 large rivers. The crease in your left hand is the Sacramento River while the crease in your left hand is the San Joaquin. The 2 rivers meet at the Delta and run out of the Central Valley down the place where your hands meet into the San Francisco Bay.
6. Ask the students whether this model can be used for other watersheds besides the San Francisco Bay watershed? Do all watersheds have high places? Do all watershed collect water into rivers? Explore the possibilities of using this model to represent your local watershed with its landmarks and special features.

4. San Francisco Bay Watershed - Assessments

Assessment

1. Have students label and color line drawing maps of California. Have them label the major landmarks (see vocabulary list) and shade in all the land that is part of the San Francisco Bay Watershed.
2. If your parents won’t go crazy with students writing on their hands, have pairs of students work together to label each other hand watershed models with a ball point pen.

Going Further

1. Do a webquest on Save the Bay’s Bay Classroom website.
2. Save the Bay has written an excellent map reading lesson, “Mapping your Watershed” that provides an excellent extension of the ideas covered here. Their mapping activity also leads into the From Maps to Models activity on MyScienceBox. You may download the lesson below. Teach students about the history of the Bay and make timelines to represent the major events and how they impacted the Bay.
3. Teach students about the history of the Bay and make timelines to represent the major events and how they impacted the Bay.
4. Visit the San Francisco Bay Model. The Army Corps of Engineers built a functioning hydraulic model of the San Francisco Bay that simulates the tides and currents. They have a marvelous visitor center and will give students a guided tour of the model.
5. Study the California Delta in more depth. There have been many hotly debated proposals on how to fix the delta in recent months, particularly since Hurricane Katrina. The California Department of Water Resources website provides detailed information about the Delta. The Sacramento River Watershed Program provides a listing of recent news articles concerning the state of the California Delta and the Sacramento River.

Attachment	Size
Mapping_Your_Watershed.pdf	78.14 KB

4. San Francisco Bay Watershed - Sources and Standards

Sources
Ideas
The idea for this activity came from the “Watershed in your Hands” Lesson from Save the Bay’s watershed curriculum (downloadable below). I have also seen Mike Moran, a naturalist at Black Diamond Mines, present this lesson at a teacher workshop in much the same way as I have described here – although his presentation is far better in my estimation.

Maps
Hubbard Scientific makes exceptional relief maps for most states. The California relief map is aroun $30 and is absolutely worth the cost. Students love the tactile quality of running their fingers across the mountains and much more readily grasp the idea of topographic maps in later lessons.

The USGS Store has the best deal on maps. For around $7-10 you get gorgeous relief maps and satellite images. The California State relief map is product #43555. The San Francisco Bay satellite image is #47251. You can find a map for virtually any US geographical area.

Blank line drawing California maps for students to color and label may be printed from Net State.

There are excellent free digital satellite images that may be downloaded and printed on the USGS website.

History of the San Francisco Bay
Zpub.com has published an exceptional history of the San Francisco Bay.

Save the Bay’s Bay Classroom has a wonderful, kid-friendly Bay history section.

A gorgeous book was recently put together by the Bay Institute and the Audubon Society called San Francisco Bay: Portrait of an Estuary.

The Bay Institute also has produced an excellent report about the history of the San Francisco Bay called From the Sierra to the Sea: The Ecological History of the San Francisco Bay-Delta Watershed. The full report can be downloaded for free from the internet.

The San Francisco Estuary Project has a number of excellent fact sheets that may be downloaded and printed out.

And if these aren’t enough, go to the California Academy of Science San Francisco Bay resources list. They provide a huge list of books, videos, scientific papers, curriculum guides, and more all related to the San Francisco Bay.

Teacher Training Opportunities
I attended Save the Bay’s “Gold Rush to the Golden Gate” summer teacher training which was an extraordinary experience. We camped and canoed all along the watershed, experiencing the watershed first hand and drawing connections between the various parts of the watershed through speakers, activities, and discussions. GO! It’s amazing!

The Watershed Project offers wonderful training opportunities for teachers about the San Francisco Bay and its watershed.

Standards
Grade 6
Plate Tectonics and Earth’s Structure
Plate tectonics accounts for important features of Earth’s surface and major geologic events. As a basis for understanding this concept:
f. Students know how to explain major features of California geology (including mountains, faults, volcanoes) in terms of plate tectonics.

Shaping Earth’s Surface
Topography is reshaped by the weathering of rock and soil and by the transportation and deposition of sediment. As a basis for understanding this concept:
a. Students know water running downhill is the dominant process in shaping the landscape, including California’s landscape.
b. Students know rivers and streams are dynamic systems that erode, transport sediment, change course, and flood their banks in natural and recurring patterns.
d. Students know earthquakes, volcanic eruptions, landslides, and floods change human and wildlife habitats.

Attachment	Size
Watershed_in_Your_Hands.pdf	82.38 KB

5. From Maps to Models - Logistics

Time
135-150 minutes (approximately 3 class periods)

Grouping
Teams of 2-4 students (I found this activity works best with groups of 3. Students stay engaged and can get access to the materials, but as a teacher, you don’t need to provide as many sets of materials as with groups of 2.)

Materials
The class needs

• several example topographic maps for students to examine before they begin (see Sources section below)
• optional (though highly recommended) – raised relief map of state or local area (see San Francisco Bay Watershed – Sources for information on where to buy these maps)

For the clay model each group needs

• 1 fist-sized lump of synthetic Plasticine clay (Play-Doh will work, however, it is somewhat water-soluble and therefore becomes slimy after the water box step.)
• 1 small bead of clay of a different color (for marking the top of the mountain)
• 1 half-sheet of transparency film (the sheet of transparency needs to fit inside the plastic container below)

For making the topo map from the model each group needs

• 1 full-sheet of transparency film
• 1 fine-tip Sharpie or overhead marking pen (Permanent pens won’t smudge if a drop of water gets on their map. On the other hand, students can’t make corrections if they make a mistake.)
• 1 plastic shoebox-sized container, at least 8 cm (3 inches) tall (The ones from the Watersheds and Wetlands activity work fine.)
• 1 flat, transparent lid for the plastic container (Most plastic storage containers come with textured, opaque lids. You need something like a sheet a clear Plexiglas that can sit over the top of the box and which students can write on. I recently discovered these plastic salad boxes at Smart and Final that provide a container and a lid in one!)
  
  
  

   
• access to a pitcher of water with 4 drops blue food coloring (I had 2 teams share 1 pitcher)
• 1 plastic ruler

For making models from topographic maps each group needs

• 2 copies of a topographic map (1 original and 1 photocopy)
• 1-2 pairs of scissors
• 1 ruler
• 1 fine-tip Sharpie or overhead marking pen
• one of the following:
• • 7-8 clear, stacking salad tray tops (available at Smart and Final or other restaurant supply stores)
  • 3-4 sheets cardstock paper and a lemon sized ball of clay
  • 3-4 sheets of EVA foam
    
    
    

     
  • 1 fist-sized lump of Plasticine clay

Setting
classroom

5. From Maps to Models - Background

Teacher Background
Topographic maps are often very difficult for middle school students to understand. They are covered in squiggly lines and unfamiliar symbols and bear little resemblance to the road maps and political maps students may be more familiar with. The key is to use models to help students make sense of these maps.

What is a topographic map (or topo map)? These maps provide a way of showing a 3 dimensional landscape on a 2 dimensional surface. The most distinctive features of a topographic map are the contour lines. Each line represents an imaginary line that connects points that are the same elevation above sea level. Thus, if you walk along a contour line, you would not climb up or down, but stay at the same elevation at all times. USGS maps, the standard topographic map, draw contour lines in brown, labeled at intervals with numbers that represent the elevation above sea level or, in the case of bathymetric maps, the elevation below sea level. Other colors you might find on USGS topo maps are green for vegetation, blue for water features, red for major roads, and grey or black for human developments such as smaller roads, railroads and buildings.

Topo maps are used by most often for navigation so that hikers and explorers can get a sense of the terrain. They are also used by scientists to observe things based on their location and their elevation.

Contour lines are spaced at regular intervals (every 10 feet above sea level is marked with a different line for instance). Thus, the closer 2 lines are together, the steeper the area. Hills can be identified by concentric circles that grow smaller and smaller until you reach the peak of a hill. Depressions such as a dried out pond or the crater of a volcano are generally shown with hatched contour lines.

Student Prerequisites
Familiarity with reading other types of maps – political maps, raised relief maps, road maps, etc. – is useful.  I highly recommend Save the Bay’s “Mapping your Watershed” activity that can be downloaded at the bottom of the San Francisco Bay Watershed – Sources section.

5. From Maps to Models - Getting Ready

Getting Ready

• Gather a set of topographic maps for students to examine.
• Display a raised relief map if you have one.
• Gather materials for making clay models: clay and transparency film
• Gather materials for making topo maps from models: transparency film, fine-tip marker, plastic container with clear lid, pitcher of blue water, and ruler
• Gather materials for making models from topo maps: 2 copies of a topo map, scissors, ruler, markers, and one (or more) of the following:
• • 7-8 clear, stacking salad tray tops (available at Smart and Final or other restaurant supply stores)
  • 3-4 sheets cardstock paper and a lemon sized ball of clay
  • 3-4 sheets of EVA foam
  • 1 fist-sized lump of Plasticine clay
  • You will want to try this activity yourself before you do it with the students. The model you make from the topo map can serve as an example for your students to emulate.

5. From Maps to Models - Lesson Plan

Lesson Plan
Introduction and Making Clay Models

1. Tell students that when we study watersheds it is useful to know how the land dips and rises – where the hills, valleys, ridges, stream beds, and plains are. Most maps don’t tell us this information. They may show cities, roads, and rivers, but not valleys, ridges, and mountains. Tell students that there is a special type of map called a topographic map that does show how the land rises and falls.
2. Give students copies of various topo maps. Ask them what they notice. Have them trace a contour line and tell them what a contour line is. Have them notice how some lines are labeled with the elevation. Have them look for hills by finding concentric circles. Have them look for steep places by finding lots of lines close together and look for flat places by finding lines spaced very far apart. If you have a raised relief map available, help students draw comparisons between the two and see a relationship between these two types of maps. Their understanding will be, and should be, very superficial at this point.
3. Tell students that over the next few days they will be making a model clay island, making a topo map of their island, giving their topo map to another group, and that other group will try to recreate their island using clay or other materials. Divide students into groups.
4. Give each student their first set of materials for making clay models and give them rules for their islands:
   • islands should fit on their transparency
   • islands should have high and low regions such as mountains and valleys
   • islands should not have extremely steep cliffs or overhangs
   • islands should not be too complicated
   • on the highest point of the island, place an “x” using the other color of clay
5. Give students 15-20 minutes to make their islands. Circulate among them making sure they are following the rules. Groups that finish early can add features such as a peninsula near the water, a stream coming down the mountainside, etc.

Making a Topo Map of the Model

1. Using one of your students’ clay models, demonstrate the procedure for making the topo map.
2. Use the marker to label North, South, East and West on the transparency below the clay model.
3. Label the compass points on the large sheet of transparency as well.
4. Place the clay model in the bottom of the plastic container.
5. Place the lid over the container with the transparency on top, oriented the same way (according to the compass points) as the clay model below.
6. Holding your head very still above the lid, trace the shoreline of the island onto the transparency using the marker. Also trace the cross at the top of the tallest hill. This cross will be a reference point to help figure out where to put your head.
7. Remove the lid. Holding a ruler inside the container near the base of the island, pour blue water into the container until the water is 1 cm deep. Notice how the water creates an imaginary line where the elevation above “sea level” is 1 cm all the way around.
8. Replace the lid and the transparency, making sure the transparency is oriented correctly. Match the first coastline and the cross to the island below.
9. Again, holding your head very still, trace the new shoreline of the island – where the water level touches the model. (You can probably end the demonstration here. Students should continue onto the next step.)
10. Repeat adding water and tracing new contour lines until the island is completely submerged.
11. Give students the second set of materials. My students needed 30-45 minutes to create their maps.
12. When all the students are finished, you can assess their understanding so far by placing all the models up at the front of the room and collecting all the maps. Place a map on the overhead projector and look at its features. See if students can tell which model it belongs to. Use features such as the number of hills, distinctive coastlines, valleys, etc. to help students identify which model goes with which map.

Making Models from a Topo Map

1. Make a photocopy of each map. The original map should be left as untouched as possible while the photocopy is a working copy that may be cut up if necessary.
2. Using one of the students’ topo maps, demonstrate how to make a model from a topo map. See the table below:

   Salad Tray Tops	Cardstock Paper	Foam	Clay
   1. Trim the photocopy of the map so that it just fits on the flat bottom of a tray. 2. Trace the outermost contour line onto the first tray. 3. Trace the next contour line onto a second tray and stack it on top of the first. 4. Continue tracing and stacking until all contour lines have been traced.	1. Make a bunch of balls of clay approximately 1 cm tall. 2. On the photocopy of the map, write an “N” on the inside of each contour line on the North side of the island. 3. Hold the photocopy tightly on top of a piece of cardstock. Cut both the photocopy and the cardstock together along the outermost contour line. Label the north side of the cardstock with an N. Set this piece aside. 4. Hold the now smaller photocopy onto a new section of the cardstock and cut out the next contour line and label the north side. Stack this new piece of cardstock on top of the first using some clay balls as spacers to raise it up off the first. 5. Continue cutting out pieces of cardstock and stacking them until all contour lines have been cut out.

 

Give each group the original and photocopy of a different group’s topo map as well as the other materials. If you want, have students use the maps to predict what the model will look like before they actually make the model. Allow students 30-45 minutes to create their models.Once all the models have been completed, put the original model, the map, and the second model side by side. Were there any problems? How similar are the two models? How are they different? Why aren’t they exactly the same? Look at the models to discover how different features (hills, valleys, ridges, plateaus, etc.) appear on the maps.If you have time, go back to the example topo maps that were shown at the very beginning of this lesson. See whether students are able to identify elevations, features, and identify trends on the maps now.

 

1. On the photocopy of the map, write an “N” on the inside of each contour line on the North side of the island. 2. Hold the photocopy tightly on top of a piece of foam. Cut both the photocopy and the foam together along the outermost contour line. Label the north side of the foam with an N. Set this piece aside. 3. Hold the now smaller photocopy onto a new section of the foam and cut out the next contour line and label the north side. Stack this new piece of foam on top of the first, orienting the north sides the same way. 4. Continue cutting out pieces of foam and stacking them until all contour lines have been cut out.

1. Roll out a sheet of clay that is approximately 1 cm thick. Make the sheet as even as possible. 2. Place the photocopy on top of the clay sheet and trace the outermost contour line with a pencil. You should create a shadow of the pencil line on the clay below. 3. Use the pencil, a popsicle stick or fingers to cut the clay along the contour line. 4. Roll out a new clay sheet and trace the next contour line on it. Cut another “pancake” and stack it on top of the first. 5. Continue rolling out, cutting and stacking new clay sheets until all contour lines have been cut out.