Project Tank World
The Citrine Band (10 year olds) group project for the Water Arc was a complex and delicate undertaking that took the patience and care of each member of the band. Rich, their collaborator, tells the story:
The Citrine band chose to explore the concept of water by building aquaria and taking regular visits to Mountain Lake in the Presidio. During the first two months of the Arc, the students built 12 aquaria of different sizes, ranging from large planted tanks aiming to recreate an Amazon floodplain, small bottle aquaria ecosystems, and re-creations of Mountain Lake.
Project Tank World proved to be far more complicated than we initially imagined. Working together with limited resources and taking into account certain scientific and artistic concepts has led to students practicing slowing down, giving and receiving feedback, working collaboratively, and above all else, being intentional.
We began exploring the artistic aspect of aquaria by looking at examples of how dedicated hobbyists set up their tanks, analyzing their design choices, with a focus on flow and movement of the viewer’s eye. Each aquarium began with inspirational photos, an emphasis on aesthetics, drawings and background research. Then an understanding of microbes, microfauna, nutrient cycling, and filtration became necessary. Trips to different aquarium stores gave the students further inspiration, and opportunities for interactions with experts from which questions could be asked.
Through building fish tanks, the band entered the world of water chemistry. Each batch of water added required dechlorination, pH, hardness, and alkalinity adjustments. Looking for specific water compositions, the students added carbonates and minerals to chemically dechlorinated tap water until their desired hardness and alkalinity was reached. pH adjustment followed. Almost every day we mineralized and adjusted the pH of water we mixed up for our growing number of tanks. Each batch required dechlorination, pH, hardness, and alkalinity adjustments. Our tank of local pond water had a high mineral content and pH, while some of our small bottle aquaria were the opposite. The students mixed what they call “universal water,” a middle ground they could dilute or add to for their own specific needs.
This daily activity was supported by background information focused on pH and water hardness. Once the basics of water chemistry were established, the students applied their chemical understanding to pushing the limits of color changing solutions to aid crustaceans with their molts, and other aspects of our daily creature tendings and chemistry tinkerings. We acidified water with CO2 gas, and used our water treatment chemicals to create a precipitation reaction. Experiments like creating solid chalk from two liquids brought life to the otherwise invisible, and also a little more understanding to the dance of chemical symbols on the white board.
Their experience with water testing allowed them to find common ground with a scientist working with the Presidio Land Trust. On a walk to the park, we saw park employees sampling the water to test the chemical water parameters. When they returned to shore and explained what they were doing, the students said, “Oh yeah, we do that too”, which led to a conversation about the lake and what the band has been doing back at school, after which the students returned to my side of the shore very proud and excited to share.
We’ve also learned about local natural history and ecosystems in general. In regards to the study of ecosystems, our tanks and bottle aquaria are a wonderful window, or microcosm through which we learn. We grow bacterial biofilm to remove waste, pump CO2 for plant growth, and adjust water parameters to mirror certain kinds of biomes.
In the park, the kids have identification skills that rival a park ranger’s. They can identify an uncommon hawk by call alone, unearth hidden puffballs, separate crustaceans from aquatic insects, and make sure that everyone on the beach saw the migrating bufflehead duck’s high speed water landing.
We’ve incorporated math into many aspects of our day. Setting up a fish tank correctly, and purchasing items (for the group and individually) has required the students to run numbers through their heads on a regular basis, and we are not shy about using math to our advantage. Diving deeper, the identification of an unknown variable in an equivalent fraction has been a throughline in our Water Arc math practice, and will continue to be a useful tool to the children as the year progresses. Some ways in which we have been using the math concept are:
Caterpillar Olympics turned into speed calculations! We asked; how do we calculate meters per hour from centimeters a second? What is speed (distance/time), how do we calculate it, and what are different ways to measure it?
Our Halloween haunted hallway included a guessing game, where visitors estimated the amount of Daphnia crustaceans living in a beaker. After calculating the amount to find the winner of the game, we also explored data collection and sampling protocol.
In preparation for making models during the next arc, we began practicing calculating scale and proportion. Cardboard fish were the subject, the students making identical ones of many different sizes.