Modeling Bay & Watershed Science

“Scientists use models to understand how a big thing works. You can use different materials to represent things in the world. If you want to do an experiment about the ocean, you can make a model of the ocean. If your experiment doesn’t work, it’s not like you’re going to mess up the whole ocean!”
Eve, Fourth Grade Student, John Muir Elementary School, Martinez 

KIDS for the BAY students from John Muir Elementary School in Martinez gathered eagerly around their three-dimensional models of the San Francisco Bay estuary, buzzing with excitement as they waited for the signal to begin their experiment. When KftB Educator Anaïs Wilson said the magic word, “Watershed!” students began to pour yellow and blue water into their models. They exclaimed in wonder as the water, rushing under their clay bridges and around their model islands, collided and began to mix in an area in the center of the model that represented the San Francisco Bay. 

Using their knowledge of the different bodies of water in the San Francisco Bay Area, students worked together to create three-dimensional bay-estuary science models. They studied colorful satellite maps and then molded accurate representations of Bay Area bridges and landmarks out of clay. “The Golden Gate Bridge is like the gateway to the bay, so I’m going to place it where the Pacific Ocean meets the San Francisco Bay!” explained Jayla. 

Before they began their watershed science experiment, students discussed why scientists use models. “To experiment and test things out,” suggested Truitt. Our young scientists were excited to predict what might happen when they poured freshwater over the rivers and saltwater over the Pacific Ocean in their models. “I predict that freshwater from the rivers will flow into the bay and mix with the saltwater,” said Niko. After pouring freshwater (dyed yellow) and saltwater (dyed blue) into their models, students shared their observations. “The colors mixed and the water turned green!” exclaimed Naomi. “The colors mixed together near the Bay Bridge,” observed Alonso. “Water is also mixing in the San Pablo Bay,” Kairo noticed. 

For the next step in their experiment, students gently shook their models back and forth to simulate tides. “The water was mixing everywhere once we added tides,” observed Lottie. Students also noticed that water did not mix evenly throughout their models. “The water is yellowish-green and more yellow near the Sacramento and San Joaquin rivers,” said Charlie. “There is more yellow where the rivers enter the bay,” agreed Alexa. “The water is bluer and more salty near the Golden Gate Bridge,” added Kayvon. “The mix of yellow and blue water represents the mix of fresh and salty water, which is called brackish water,” concluded Lila. By watching their models in action, students observed how local bodies of water, including the San Joaquin and Sacramento Rivers, the San Francisco Bay, and the Pacific Ocean, are all interconnected.

KftB Educator Neda Ibrahim added a drop of red dye, representing a large pollution event, such as an oil spill, to each bay model. Students at Burbank Elementary School in Hayward exclaimed in distress as the dye began to spread throughout their models. “The pollution spread and all of our animals died,” said Rohan. “I have seen dolphins by the Golden Gate Bridge! In our model, the pollution spread all the way past the Golden Gate bridge and into the Pacific Ocean, infecting all the dolphins and whales,” said Kyan. “The pollution spread because all the water is connected, and now all the water is dirty,” reported Kenia. “Pollution doesn’t stay in one place, it spreads and hurts people and animals!” said Cara.

Observing how pollution can spread throughout connected watershed habitats, students discussed types of pollution and the impacts on wildlife and communities of people. They brainstormed examples of pollution they have observed in their own daily lives. “Garbage is pollution. Cars also cause pollution,” said Esmeralda. “The Fourth of July causes a lot of smoke pollution,” said Camila. “Boats can deliver oil and if there’s a crash, the oil can spill and kill a bunch of species in the bay and ocean,” said Nicolai. “Things that can’t be recycled, like candy wrappers and chip bags, are examples of trash pollution,” suggested Angelo. “Power plants make smoke that spreads around the whole world,” said Merill. 

Our student Environmentalists’ gained a new understanding of how watersheds are connected, and of how easily pollution can spread through these environments. This knowledge developed their determination to prevent pollution from reaching local waterways and spreading throughout their watersheds, and eventually, the whole world. Studying the watershed, first in a localized context and finally a global one, encouraged our young Environmentalists to take responsibility for their watershed environment and inspired them to protect it for all to enjoy, learn and play in. “I don’t think anybody should have to live in a polluted environment!” exclaimed Joziah. “We have to take action to protect our watersheds!”