This box covers watersheds, wetlands, and the shaping of the San Francisco Bay Area. Students will create several 3 dimensional classroom models to explore watersheds, erosion, sedimentation, and wetlands.Students will explore the geography of the local area through maps and physical exploration, thereby learning where water in the Bay comes from and the path it takes before it reaches the ocean. Throughout the unit are strategies to apply classroom learning to the real world in the form of:
Summary
In this lesson, students review the water cycle (a concept most have hopefully explored before in elementary school science) and write stories to describe the journey of a water molecule through the water cycle. They begin by labeling a drawing of the water cycle, noting the locations that water may be stored on the planet and the processes through which water travels from one location to another. They then envision several journeys as a class before writing a story to describe the journey of a water molecule through the water cycle. An optional mini-investigation to complement this lesson involves observing the transition of water through its 3 phases (ice, water, water vapor) after an ice cube is zipped into a resealable plastic bag and taped to a sunny window.
Objectives
Can list the 3 phases of water and understand how heat contributes to the transition from one phase to another.
Can discuss the various locations where water is stored on Earth and the processes through which water travels from one location to another.
Can describe the water cycle.
Vocabulary
Water cycle
Soild
Liquid
Gas
Evaporate
Condense
Precipitate
Groundwater
Percolate
Transpire
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:
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:
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.
Getting Ready
For water cycle discussion:
Lesson Plan
Optional mini-exploration:
Assessment
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.
Summary
Cardstock paper, water spray bottles, markers and sponges are turned into models of wetlands and watersheds in this simple activity. Students follow the path of the water (and urban runoff) to a bay and develop an initial understanding of what watersheds are. Then some students add sponges to the borders of their bay to simulate wetlands and compare watersheds with wetlands to those without. Students extrapolate the role of watersheds as reservoirs in times of drought, as sponges in times of flood, and as filters for pollution. Finally, students compare watersheds with wetlands to those without after a “toxic chemical spill” (Koolaid drink mix) to see the effects of pollution throughout the watershed as well as to discover the role of wetlands in reducing the harm of severe pollutants to a bay. This series of activities is an excellent prelude for a wetlands restoration field trip (see the Save the Bay field trip planning guide) so that after learning what wetlands are, they can explore and restore a wetland area firsthand. Another extension and application of these ideas might be an exploration of the students’ own watershed, the effects of urban runoff and watershed protection.
Objectives
Can define wetlands and watersheds.
Can look at a 3-dimensional model and identify different watersheds.
Can explain how runoff carries water, sediments (from natural areas), and pollution (from urban areas) to rivers, bays and oceans.
Can understand that an event in a watershed affects all downstream areas.
Can describe some of the many important roles wetlands serve in an ecosystem.
Vocabulary
Watershed
Wetland
Runoff
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:
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:
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).
Getting Ready
Lesson Plan
Part 1 – Building a watershed
Assessment
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.
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.
Summary
Through a demonstration, students learn about the balance between subsidence and flooding in the formation of a wetland. Students then watch a short 15 minute PBS video about the wetlands of Louisiana. They will discover how levee building and the subsequent loss of wetlands contributed to the severity of Hurricane Katrina’s effect on the city of New Orleans. Finally, the class holds a discussion geared towards environmental stewardship and habitat restoration.
Objectives
Can explain how subsidence and flooding contribute to the maintenance of wetlands.
Can explain how levees prevent flooding and exacerbate subsidence.
Can explain how wetlands protect shoreline from natural disasters such as hurricanes and flooding.
Can discuss the goals of habitat restoration.
Can recognize the importance of environmental stewardship.
Vocabulary
Wetland
Soil compaction
Subsidence
Habitat restoration
Environmental stewardship
Time
45-55 minutes
Grouping
individual
Materials
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.
Getting Ready
For Subsidence Demonstration
Lesson Plan
Subsidence Demonstration
Assessment
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.
Objectives
Can feel a sense of place and connectedness to other parts of the state.
Can identify the major landmarks in the San Francisco Bay watershed.
Can see similarities between very large watersheds (on a statewide level) and very small ones (on a neighborhood level).
Vocabulary
Watershed
Estuary
Sierra Nevada Mountains
Central Valley
Sacramento River
San Joaquin River
California Delta
San Francisco Bay
Suisun Bay
San Pablo Bay
Central San Francisco Bay
South San Francisco Bay
Pacific Ocean
Time Grouping Materials
|
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).
Getting Ready
Lesson Plan
Assessment
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 around $25-$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.
Summary
Most middle school students have not seen or used topographic maps before. Conceptually, it is difficult for kids to see how a 2 dimensional topo map represents elevation. In this activity, students learn how to create and read topo maps. By the end of the activity, they should be able to read a topo map and identify simple geographical features from a map. Teams of students mold a landform out of clay then place it into a clear plastic container. Water is added to the container in 1 cm intervals and students trace the “shoreline” of their model onto a transparency placed on the box lid. The resulting topo map is traded with another group who is then challenged to turn the 2 dimensional map back into a 3 dimensional landform. Several options are provided for creating the final model based on the materials available to the class. In fact, having more than one option of how to create the model often leads to greater understanding of how topo maps represent elevation.
Objectives
Can understand the construction of topographic maps and the use of contour lines to show the Earth's surface in three dimensions.
Can identify major geographical features on a topographic map.
Can recognize what lines on a topographic map represent.
Can create a topographic map from a 3 dimensional model.
Can create a 3 dimensional model from a topographic map.
Vocabulary
Elevation
Contour line
Topographic map
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
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.
Getting Ready
Lesson Plan
Introduction and Making Clay Models
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. |
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. |
Assessment
Sources
Activity descriptions and ideas
I first learned how to make topo maps from Eric Muller of the Exploratorium’s Teacher Institute. I changed the method for making the topo map from the models but otherwise our activities are very similar. You can download his "To Topo Two" activity below or from his website with other stellar activities.
USGS has a great description of how to make 3-D model using clear, stacking, salad tray tops.
RAFT describes 2 different ways to create 3-D models. Both are downloadable below or you can access them, and lots of other fabulous idea sheets on the RAFT website. The first “3-D Viewing Topo Lids” uses clear, stacking, salad tray tops. The second, “Making Mountains” uses EVA foam.
If you are an NSTA member, Science Scope had a fabulous article in its October 2005 issue called “Making Sense of Topographic Maps”.
Topographic map information
The best place to learn more about topographic maps is the USGS. For more information about the symbols commonly found on topo maps, see the USGS map symbols page. For more information about how topo maps are created and what they are, see the USGS topo map information page.
Materials
S&S Worldwide has the best deal on EVA foam at $13 for 78 sheets.
Standards
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:
f. Read a topographic map and a geologic map for evidence provided on the maps and construct and interpret a simple scale map.
Summary
Once students understand the basics of how to read and create a topographic map (see From Maps to Models lesson), students will study and label a topographic map of their local watershed. They will identify the creek closest to their school and mark the boundaries of their watershed. In the process, they practice recognizing hills, ridges, valleys, stream beds and other geographical features on a topographic map. Finally, students take their maps and walk a part of their watershed, matching their maps to their real world surroundings. If a walk through your neighborhood is not possible, the lesson can be conducted without the watershed walk. The watershed walk portion of this lesson may be combined with the Sediment Study Project.
Objectives
Can understand the construction of topographic maps and the use of contour lines to show the Earth's surface in three dimensions.
Can identify major geographical features on a topographic map.
Can recognize what lines on a topographic map represent.
Can correlate real world topography to contour lines on a topographic map.
Vocabulary
Elevation
Contour line
Topographic map
Time
30 minute to study maps in the classroom
45-55 minutes to walk the watershed
Grouping
individual
Materials
Teacher Background
Information about topographic maps, how they are drawn, and what the symbols on them mean can be found in From Maps to Models Background or at the USGS website.
It is important to show students why a topographic map is useful in the real world, and not just as a classroom exercise. Students tend to be familiar with reading regular road maps. It’s important to show students that when contour lines are overlaid on a regular map, information about the topographical landscape is revealed in the patterns among the swirls and squiggles of the contour lines.
The way I conduct my classes is first by showing my students a topo map of the neighborhood immediately surrounding the school then taking them on a walk that highlights the changes in local geography including a hill, a ridge, and a creek-carved valley. Each of these geographical features are important for geologists and other scientists to be able to recognize on a topo map. In my classes, the watershed walk was combined with the Sediment Study Project. Different classes went to different study sites along the creek (source, mid-stream, and mouth) to observe the flow of water and collect sediment samples. On our way there, we plotted a course that would take us by interesting geographical features that can be identified on the map. Before heading back, the students plotted a return route that minimized sudden elevation changes. The precise routes and features to visit will depend on your own local geography. Suggestions are included within the lesson plan below.
If a walk through your neighborhood is not possible, do the classroom portion only.
Student Prerequisites
Previous experience reading and/or creating topographic maps.
Getting Ready
Lesson Plan
Mapping your Watershed
Assessment
Sources
The US Department of Agrictulture’s Natural Resources Conservation Service has a useful handout about reading topographic maps and how to delineate watersheds using a topographic map. The simplified drawings on these pages are great simplified topographic maps to use with students.
If you want to find a specific type of geographical feature to show students how this looks on a topo map, see the Rocky Mountain Resource Center. They have compiled example maps for hundreds of interesting features that may be shown to students.
Standards
Grade 6
Shaping Earth’s Surface
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.
Investigation and Experimentation
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:
f. Read a topographic map and a geologic map for evidence provided on the maps and construct and interpret a simple scale map.
Summary
This lesson is an extension of the GEMS guide: “River Cutters” by the Lawrence Hall of Science (see note below). In the GEMS curriculum, students are introduced to erosion by modeling the formation of rivers in tubs of diatomaceous earth, a silt-like substance into which meandering river channels and deltas form. This lesson builds off of the River Cutters activities by using a combination of sediment types in the models. They observe how gravel and large particles of sand remain in place whereas silt is washed downstream in fast flowing river channels. In contrast, where the water velocity slows as it reaches the newly forming bay, a beautiful silt-covered delta forms. These observations lead students to the conclusion that fast moving water picks up the smaller sediment particles and eventually deposits them in places where the water slows. Students can then take this theory to test it out in real world conditions at a local creek in the Sediment Study Project, observing sediments and water velocity at different sites along a creek’s length. The concept of how sediments are deposited becomes a core feature of subsequent geology lessons and investigations in which the environmental conditions surrounding the formation of large particled conglomerates may be differentiated from small particled shales and siltstones.
Special Note: This lesson plan is written with the assumption that students have some experience using the river models in the GEMS guide “River Cutters”, written by Cary Sneider and Katharine Barrett and produced by the Lawrence Hall of Science. In this guide, students make observations of rivers carved in just silt (diatomaceous earth), sequencing events in time, noticing patterns, recording information, and acquiring the terminology necessary to describe common erosion patterns. My students completed the first 5 sessions of River Cutters although completing the first 3 lessons is sufficient. So as not to infringe upon the copyright of the GEMS unit, only the extension activity is described here.
Objectives
Can describe the major types of sediment.
Can identify common river features and erosion patterns such as a river’s source, channel, mouth, delta, etc.
Can model sedimentary deposition patterns.
Can explain how sediment size and current velocity affects deposition.
Can make observations and record data in a science lab notebook.
Can draw conclusions from data.
Vocabulary
Erosion
Sediment
Load
Deposition
River source
River channel
River mouth
Delta
Bay
Silt
Sand
Gravel
Time
15 minutes – Set stage for the experiment
20 minutes – Run single sediment and mixed sediment rivers side by side
15 minutes – Teams make individual conclusions and clean up
15-20 minutes the following class period – Combine all data and make summative conclusions
Grouping
Teams of 3-4 students. Half the teams will set up tubs with a single sediment (diatomaceous earth). The other half will set up tubs with a mixture of sediments (diatomaceous earth, playground sand, and aquarium gravel).
Materials
For Soil Separation Test Demonstration
Sources
The primary inspiration for this unit is the GEMS guide “River Cutters”, written by Cary I. Sneider and Katharine Barrett and produced by the Lawrence Hall of Science. I strongly recommend this guide, even if you don’t intend to use it because they offer fabulous tips and recommendations for using river cutter tubs with students. In addition, the guide provides fabulous diagrams, handouts, homework assignments, suggestions, resources and more that can be used as a prelude or complement to this activity.
For more information about erosion and sediments:
Standards
Grade 6
Shaping Earth’s Surface
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:
Students know water running downhill is the dominant process in shaping the landscape, including California’s landscape.
Students know rivers and streams are dynamic systems that erode, transport sediment, change course, and flood their banks in natural and recurring patterns.
Students know beaches are dynamic systems in which the sand is supplied by rivers and moved along the coast by the action of waves.
All grades
Investigation and Experimentation
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.
Teacher Background
Erosion is the process by which sediments are transported by wind, water, ice, or gravity. Often people mistake erosion for weathering, the process through which rocks are gradually chipped away by abrasion, water, and ice into sediments, a topic that is studied in greater detail in the Geology Box. On the other hand, erosion is the movement of these sediments from one place to another. Erosion is a very natural and essential natural process upon which many ecosystems depend including beaches, deltas and wetlands.
The central aspect of this activity is the observation of differences in sedimentation patterns based on the velocity of water movement. The central principle is as water moves faster, it can carry larger sediments and more of them. The smallest sediment particles (silt and clay) are picked up first, followed by sand then gravel. Thus, a rain-swollen river will carry a great deal of sediments of all sizes while a slow, meandering stream will carry very little and only of the smallest sizes. As the current velocity slows, sediments are deposited in reverse order, gravel is dropped first, then sand, then silt and clay.
In most watersheds, rivers begin in the high mountains with steep slopes, and thus, with fast running water. The smallest sediments are quickly borne away, leaving behind the gravel and larger rocks. As the slope of the landscape lessens in the foothills, the river slows and sandbars may accumulate along the curves and twists of the riverbed. Finally, as the slope becomes nearly flat, either upon reaching the valley floor or as it reaches a body of water such as a lake or bay, the current velocity is reduced to a crawl and even the smallest sediments are deposited, leading to silt-covered deltas and clay-like mud covering the bottom of lakes and bays.
All of these processes may be observed in the river models in which silt from the faster flowing river channels is picked up by the water and deposited when the water slows in the bay at the base of the model, eventually forming a delta. The sand and gravel in the upper regions of the model are gradually exposed. If your students do the silt only river models described in the GEMS guide “River Cutters” they will soon discover that the rivers formed in the mixed sediment rivers are slower to form, straighter and shallower, more similar to a young river, owing to the higher percentage of gravel and sand which are not as readily carried away by the water.
In my classes, I spend 1 class period introducing the activity, conducting the experiment, and allowing students time to make observations and draw individual conclusions. I spend the second class period in a group discussion, leading students towards a clear theory to explain their observations.
Student Prerequisites
Students need hands-on experience with soil separation tests in order to see how the smallest particles of sediment stay suspended in agitated water longer than larger sediments (see the Soil Analysis lesson). Although this is used as a demonstration before beginning this lesson, students recognize the patterns and their implications best when they make the discovery themselves.
In addition, it is strongly recommended that students complete a minimum of the first 3, and preferably, the first 5 sessions in the GEMS guide so that students have experimented with time (how long a river has been running) and with slope before adding the variable of multiple sediments to the model.
Getting Ready
Setting up the demonstration
Working the dripper systems
Lesson Plan
Introducing the activity
Assessment
Summary
In this culminating project, students go out into the field and test their theories about erosion and sedimentation at a local creek. How are sediments distributed along the creek? Does it vary by location (the source, mid-stream, and the mouth)? Does it vary by the velocity of the current? Different classes can collect information for the different study areas. At a study site, they will draw maps, measure the velocity of the current, and collect sediment samples from the creek bed. These samples are analysed back in the classroom for the percent of different sediments they contain. Finally, students stand back and examine their data to try to make sense of the sediments they find. If it is not possible to bring students to a creek, there are many ways to bring the data to them. Collect the sediment samples yourself with photos and water velocity information OR use the Suspended Sediment Database to draw your conclusions. This USGS database provides stream flow and sediment information for over 1,500 rivers and creeks nationwide (see the Going Further section for more information on using the USGS’s database).
Objectives
Can describe the major types of sediment.
Can explain how sediment size and current velocity affects deposition.
Can create a hypothesis and make predictions of what to expect from experimental data based on prior knowledge.
Can make observations and record data in a science lab notebook.
Can use their own observations and data draw logical conclusions.
Time
Day 1: Experimentation (may be split into two days)
20 min describe the question and experiment and have students make hypotheses and predictions
5 min describe experiment procedures
30-45 min conduct experiment and collect sediment samples at the study site
travel time to the study site and back will vary
Day 2: Soil Separation Tests
10-15 min set up soil separation tests
Day 3: Data Analysis and Summary
15-20 min analyze soil separation test results
10 min summarize group results and display
Day 4: Drawing Conclusions
45-50 min discuss results and draw conclusions
Grouping
Teams of 3 students
Materials
For sediment study, each group of students needs: (I assembled all the materials into several shoebox-sized plastic containers to become our class set of “creek kits”. Many of these items are the same as those needed for the Habitat Survey lesson.)
Day 2-4 – Classroom.
Teacher Background
See Erosion Patterns Background for information about erosion and typical sediment deposition patterns.
In this project, I wanted students to grapple with the notion that science is rarely as simple as the textbooks. Usually, in a river, stream or creek bed, a fast-flowing midstream section will have lots of gravel and larger rocks and the mouth will have lots of silt and clay as the current slows. Usually, the riverbed at source will have whatever type of soil the surrounding hillsides are made of. However, in real life, things are rarely so simple. There are culverts that direct creeks underground, man-made concrete channels, and dams. There are polluters, dogs and gardeners to contend with, all of whom affect the types of sediments one will find in any given spot in an urban creek.
The beauty of this project is that the ability of fast-moving water to carry more sediment of larger sizes is so robust that irrespective of the other variations, if there is sediment at all to be observed, it will almost certainly follow this trend. Most importantly, students are able to look for patterns in real world data and consolidating everything they have learned about watersheds and erosion. Surprises come from changing students’ expectations of what a creek looks like at different places and from discovering the variability of data, even at a single study site.
Water at creek source:
|
|
Water at mid-stream: | |
Kids at creek mouth: | Water at creek mouth: |
In this project, different classes of students go to one of 3 sediment study sites to collect information. Students lay out a 4 meter transect line to create 5 imaginary lines stretching across the creek. Students do the following:
Getting Ready
For sediment study at the creek:
Lesson Plan
Day 1: Experimentation
Day 2: Soil Separation Tests
Day 3: Data Analysis and Summary
Line 1 | Line 2 | Line 3 | Line 4 | Line 5 | Average | Percent | |
Silt/clay | |||||||
Sand | |||||||
Gravel | |||||||
Organic material |
Going Further
Standards
Grade 6
Shaping Earth’s Surface
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.
c. Students know beaches are dynamic systems in which the sand is supplied by rivers and moved along the coast by the action of waves.
All grades
Investigation and Experimentation
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.
Summary
Students go on a web-quest for information on Save the Bay’s Bay Classroom website. They discover facts and information about the part of the San Francisco Bay, its history, the creatures that call it home, and ways they can help protect the bay. This easy activity requires little supervision and is thus offered as a great substitute teacher lesson plan or for one of those teaching days when you need a last minute lesson. Suggestions for making this lesson more interactive are provided.
Objectives
Can identify the major events that contributed to the current state of the San Francisco Bay.
Can describe some of the plants and animals that live in the Bay.
Can explain the importance of the San Francisco Bay and its watershed to the state of California.
Can describe some things students can do to help protect and preserve the Bay.
Vocabulary
Watershed
Estuary
Hydraulic Mining
Time
45-55 minutes
Grouping
Individual. An option for coming back together as a class to discuss students’ findings is provided.
Materials
Teacher Background
See San Francisco Bay Watershed – Background.
Student Prerequisites
None, although familiarity with the San Francisco Bay watershed is helpful.
Getting Ready
Lesson Plan
Option 1 – Individual Web-quest
Assessment
Going Further
Standards
Grade 6
Plate Tectonics and Earth’s Structure
1. 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
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.
Ecology (Life Sciences)
5. Organisms in ecosystems exchange energy and nutrients among themselves and with the environment. As a basis for understanding this concept:
e. Students know the number and types of organisms an ecosystem can support depends on the resources available and on abiotic factors, such as quantities of light and water, a range of temperatures, and soil composition.
Summary This section will give you information to help you plan a field trip to the San Francisco Bay Model. The Bay Model is a working three-dimensional model of the San Francisco Bay and Delta areas. It fills 3 warehouse sized buildings and students who visit get a guided tour, observing the flow of the water, learning about how scientists use scale models, and leaving with the impression that the Bay is a very big place. |
Time
2 hours at the Visitor Center plus travel time
Planning Guide
According to the Bay Model Visitor Center:
“The Bay Model is a three-dimensional hydraulic model of San Francisco Bay and Delta areas capable of simulating tides and currents. The Model is over 1.5 acres in size and represents an area from the Pacific Ocean to Sacramento and Stockton, including: the San Francisco, San Pablo and Suisun Bays and a portion of the Sacramento - San Joaquin Delta.”
According to my kids:
“It’s HUGE!”
“Wow.”
“Check out how shallow the Bay is!”
You need to make a reservation for groups. With your reservation, students are taken on a ranger-guided tour of the facility. I asked my students to fill out a handout as they visited the museum. You can adapt the handout to suit your need by downloading it below.
Time at the Bay model passes quickly. 1 minute = 1 hour and 40 minutes in the real world. Thus, you can see the tides going in and out and watch the currents flow through the Golden Gate.
You can schedule a ranger led tour by contacting the Bay Model at:
Bay Model Visitor Center
2100 Bridgeway
Sausalito, CA 94965
Phone: (415)332-3871
Fax: (415)332-0761
Programs should be booked 3 weeks in advance and are available Tuesdays – Saturdays.
Summary
This section will give you information to help you plan a field trip with Save the Bay. I brought 32 students to Arrowhead Marsh, a hidden wetland near the Oakland Airport, to meet up with extraordinary Save the Bay Instructors. The day was divided into two parts: 1) Canoeing – where we did water quality monitoring, explored the marsh with all our senses, and went on a wildlife scavenger hunt 2) Restoration – where we repotted 300 native plants, cleaned up the shoreline, and went for a walk on a boardwalk above the marsh. Students were able to explore a wetland up close and observe a leopard shark, feel the Bay’s muddy bottom, and listen to the endangered snowy plover.
Objectives
Can apply knowledge about water quality monitoring and the role of wetlands to the San Francisco Bay.
Can conduct a scientific investigation.
Can use a field guide to identify animals in the wild.
Can participate in habitat restoration efforts.
HAVE FUN!
Time
A canoe trip alone lasts approximately 5 hours.
A combined canoe and restoration trip lasts 6 hours.
Planning Guide
Save the Bay has excellent educational staff that is very skilled at working with students. They offer canoeing programs (Canoes in Sloughs) and restoration opportunities at several sites around the Bay. You can also adopt a site and return to the same restoration site several times in a given year to assist in the transformation of a piece of wetland over time. They will even come to your classroom to do a pre-trip lesson if you wish. Given the quality of the restoration work that Save the Bay does, I strongly recommend a double program that combines canoeing and restoration work. The only drawback is that you will have less time on the water, but still enough for kids to learn and play.
The cost for programs is on a sliding scale depending on the number of students that qualify for free and reduced lunch. My students paid $30 each to attend which was well worth it.
To schedule a program, fill in the registration form available on the Save the Bay website or download it below. For more information, contact Save the Bay directly at:
Save the Bay 350 Frank H. Ogawa Plaza, Suite 900 Oakland, CA 94612 phone: (510)452-9261 fax: (510)452-9266 [email protected] |
Sample Schedule (The time and activities in your program may vary!!)
Typical Canoes in Sloughs program:
9:00am – 9:15am ARRIVAL
9:15am – 10:00am INTRODUCTORY ACTIVITIES
10:00am – 10:15am PREPARE FOR PUT-IN
10:15am – 10:30am PADDLING Instruction and SAFETY Awareness Talk
10:30am – 1:15pm ON THE WATER!!
1:30 - 2:00pm TAKE-OUT (group comes off the water)
Typical Restoration Program: