KIDS for the BAY Scientists in Distance Learning

By: Sienna Kuykendall

Which is denser, freshwater or saltwater? Let’s find out through the Eggsperiment!

After learning that our San Francisco Bay watershed is an estuary, students in Mr. Wallace’s third grade class at Manzanita Community School in Oakland were eager to conduct an experiment (Eggsperiment) to discover more about the relative density of the different types of water in an estuary. In their interactive KIDS for the BAY Zoom lesson, students learned about the concept of density with a scavenger hunt for objects of relative density in their homes. Students loved the challenge of gathering objects with low density (like a feather) and high density (like rocks) while a two-minute timer counted down! Back on the Zoom video, students did a show-and-tell. Chenoah shared, “I found a heavy vase that is very dense. I think it would sink in water.” Chloe added, “I found a light plastic animal toy. I think it would float in water because it is very light.”

This San Francisco Bay estuary satellite map shows how saltwater and freshwater, with different densities, mix in the null zone!

Students then gathered a simple list of supplies for their Eggsperiment: two cups of water, salt, two eggs, and a spoon. KIDS for the BAY Educator Sienna Kuykendall modeled and guided students in the set-up of the experiment and asked students to type their predictions in the Zoom chat: “Will the egg float in A) freshwater, or B) saltwater? Students were excited to observe if their predictions were correct. James exclaimed, “The egg in freshwater sank to the bottom of my cup but the egg in salt water floated!” Kamil made the connection, “Saltwater helps things float! When I swim in the ocean, I float very easily! But when I swim in the pool, it’s harder to float.”

One of our Young Scientists took a photo of their Eggsperiment results to share!

To further illustrate that saltwater is more dense or heavy than freshwater and how water mixes in the San Francisco Bay estuary, Ms. Sienna performed a second experiment called Estuary in a Bag. Student volunteers read the instructions as Ms. Sienna demonstrated. Leyla exclaimed, “The dark blue saltwater sank to the bottom of the bag and the clear freshwater floated above!” Using an online whiteboard Ms. Sienna illustrated how freshwater from the rivers and saltwater from the ocean form layers in the San Francisco Bay estuary and then mix in the null zone. She explained that this makes the estuary a unique habitat for many diverse organisms and shared that in their next Zoom lesson they would investigate bay organisms! The young scientists were so excited for their next KIDS for the BAY investigation!

A KIDS for the BAY student completes the Estuary in a Bag experiment during in-person learning in the classroom.
KIDS for the BAY