Eco Bay Pathways Watershed related exhibits in the Exploratorium

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1 Eco Bay Pathways Watershed related exhibits in the Exploratorium This Pathwa y is a guide to engagement wi th museu m exhibit s at the Explo ratorium and includes activiti es for p re- an d post-fi eldtri p learning. This Pathway is desig ned to help p rovide di rection and st ructure f or field trips to the Exploratorium that focus student attention on envi ro nmental science. 1. Bay Model Location: Bay 2E The Bay Model is a projected image of the Bay that shows how tides move water (and floaties) in the Bay estuary. a. If you live in the Bay Area, find your house. Mark where you live

2 b. How do the floaties move? i. Turn off the currents display. This should also turn off the colors and arrows. ii. Launch a stream of floaties 1. Launch them in South Bay, as far south as you can. a. Draw their motion below, left. 2. Next, launch them in Delta, as far up stream as possible. a. Draw their motion below, center. 3. Finally, launch them near or under the Golden Gate Bridge. a. Draw their motion below, right. South Bay Launch Delta Launch Golden Gate bridge Launch iii. Describe the movement of each floatie launch. South Bay: Delta: Golden Gate Bridge: What s going on: The San Francisco Bay is an estuary into which 40 percent of California s land area drains. This fresh water that drains from California s Central Valley and Bay Area interacts with saltwater flowing through the Golden Gate due to tidal influences. Related hands-on activities: Watershed in your hand. Watershed in a pan

3 2. Black Sand Location: Bay 4 (next to museum office) The sand in this exhibit is from the beach just outside the Exploratorium. Some of the sand is magnetic. a. Play with the sand. b. Which color sand is magnetic? How can you tell? c. How do you think this sand got outside our museum (on the beach)? d. Trace the path of a river, which can carry sand, from the Sierra Nevada Mountains to San Francisco.

4 This sand is eroded from the Sierra Nevada Mountains over 100 miles away. The black sand is a mineral called magnetite. It is a component of granite. This granite is the main rock type of the Sierra Nevada Mountain range to the east. Weathering and erosion help transport this material through our watershed and to our local beaches. From 1867 to 1887, 60 million cubic meters of suspended sediments were deposited in Suisun Bay. These sediments flowed from the Sierra Nevada Mountains as a by-product of mining activities during the Gold Rush. 3. Settling Column Location: Bay 2E the tilted tube allows sediments to flow downhill and demonstrates how sediments mix, move and flow in water. Sediments are the small particles of white sand inside the glass tube. a. Turn the column to a 45-degree angle, with the sediment at the top of the tube. Notice how the sediments travel in the column of water. b. Turn the tube over again and find examples of turbulence and deposition: i. Do the sediments settle or deposit at the bottom of the tube all at once or over time? ii. Where do you notice turbulence or chaotic flow? iii. Time how long it takes most of the sediments to collect on the bottom of the tube (again with the tube at 45 ). iv. Change the angle. What is you new angle? Time how long it takes most of the sediments to collect on the bottom of the tube. c. The water might seem cloudy for a while after the tube is tipped. Suspended sediments cause this cloudiness. The longer sediments can remain suspended in water, the further they can travel in the water s flow. Find a timer. How long does it take for the water to turn clear (for all the sediments to drop to the bottom)?

5 What s going on: This exhibit models suspension, deposition and turbulence, all of which take place in real rivers and streams. Turbulence helps keep sediments from depositing. 4. Avalanche Location: Bay 5 (near museum office) Flip an hourglass shaped chamber to see how different types of mineral grains interact and flow. a. Shake the sediments in the hourglass and then turn it upside down. b. Be sure to look at both sides of the hourglass. Notice how the sands flow and deposit in the lower container. c. Draw what you see. Draw the Avalanche pattern above. In this exhibit, particles are sorted by size, density and angularity. In watersheds, sediments are sorted differently and are deposited based on the speed of water flow as well as the size, density and angularity of the particles. Layering is a characteristic of both this exhibit as well as in the deposition of sediment in watersheds. Related hands-on activities:

6 Avalanche 5. Flow Through Location: Bay 5E In this exhibit, you will be able to see the flow patterns of moving water. You can change the patterns of flow by placing objects in the water s path. a. Remove all objects in a flow channel. b. Does all water flow at the same rate or speed in a single trough (one lane of this exhibit)? How can you tell? c. Put objects in the flow and see what patterns develop. Draw your object and the patterns that develop below. Direction of flow The foam indicates water movement. Where the foam builds-up water is moving more slowly. In a watershed, slower moving water drops its sediments more readily. Natural and man-made features can interrupt flow of water. Where water flows more slowly or creates eddies is where sediment deposition may occur. There are many structures along the Sacramento River, the California coast and other locations where there are man-made structures to control the direction and speed of water flow.

7 View of sediments blocked by jetties in Southern California. 6. Tea Leaves Location: Bay 9 (near classrooms) Spin the transparent bowl, which is partially filled with water and contains bits of confetti. For this pathway, we ll refer to the confetti as sediment particles. a. Spin the bowl. Start slowly and spin the bowl faster and faster. b. After the bowl gets spinning really fast, stop and hold the bowl. c. Right when you stop the bowl, notice where the confetti/sediments are located. Record your answer here: d. As the bowl slows down, notice where the confetti/sediments collect. Record you answer here: Did you notice how the confetti/sediments tend to congregate in the slower moving water in the middle of the bowl? Streams often bend and turn as well as carry sediments. When water goes around the outside of a bend it usually travels faster than the water located at the inside of a bend. The slower the water motion, the lower the carrying capacity it has. Stream sediments tend to drop from the water s flow on the inside of stream bends.

8 7. Seismograph Location: Bay 9E The Exploratorium seismograph records surface ground motion. When the sensor below the recording drum feels the ground shaking it makes the needle move. a. Jump up and down alone or in a group. b. Draw the seismic pattern that is recorded.

9 Draw your seismic pattern above. Devices like this record ground motion all over California. The movement of the ground (especially upward) is what created our local watershed. Related hands-on activities: Locating Earthquake epicenters 8. Evaporation (Too Slow to Notice) Location: Bay 4 (Under Mezzanine - prototyping area) Measure how fast water evaporates. a. Notice the mass on the scale i. What s the mass: b. Wait until you notice a change i. What s the mass now? c. Did the mass go down or up? d. Where did the water go? e. What would increase the rate of evaporation?

10 Evaporation is a major part of the water cycle. 9. Salt Ponds Location: Mezzanine life science area The color of the water in these tanks is caused by the presence of extremophiles (Note: The meandering shapes were not carved by the organisms, but by the exhibit developer to mimic the shapes of the streams that flow into the bay.) a. Notice the different colors in the tanks. b. Read the panel of text to the right of the tanks. What colors correspond to what concentrations of salt in ppt (parts per thousands)? i. Green = ppt ii. Orange = ppt iii. Pink = ppt Organisms that live in saline environments cause the colors. In the southern part of the San Francisco Bay, salt ponds are dammed-off areas that are allowed to evaporate. Salt is collected and sold. Wetlands are often used for salt ponds. Related hands-on activities: KQED Quest- From Salt Ponds to Wetlands Credits: Image of California watershed from: features/calwater/ Sedimentation of Suisun Bay data: KQED Quest: Other Images and resources: