Students researched the exact depths that differentiate each layer (based on how much sunlight passes through) and they spent time at the library collecting photography books of sea life. After reading about the different types of creatures that are found in each zone, the class created some beautiful observational drawings and placed them on our mural in the correct zones.Our students were especially interested in researching the coldest and darkest zone. Much of our research was focused on this lowest layer of the ocean, the Trenches or Hadal Zone. We spent time discussing the Challenger Deep (a.k.a. Mariana Trench), where some of the most primitive species on earth are found. Down there, instead of a food chain based on energy from the sun, we learned about a food chain based on the process of chemosynthesis. Students wondered how the trenches were made, which led us into a discussion of tectonic plate movements and subduction - a process leading to the formation of the deepest trench. Children were introduced (through video) to the scientists, past and present, who have ventured there and we marveled about the risks these explorers took in traveling to such amazing depths. Students were fascinated by the immense pressure and the types of vessels that are constructed for traveling to the Challenger Deep. While learning about bathymetry, and the tools that scientists use to make measurements of underwater depths, some of the students pointed out that the ocean floor maps looked similar to the topographical maps that they created last year! This astute observation is gratifying as they are making connections and beginning to understand and articulate the physical characteristics of the surface of our planet.
