The two buckets of dirt and trash represented a small landfill, and a group of teachers Wednesday searched through the remains with a screen, little shovels and their hands to find the items buried there in February.
Half of a Styrofoam meat tray and a plastic bottle were easily found, while a turquoise Post-it note, cardboard shoe box lid and a swatch of a cotton terry dish towel were found in decomposing pieces. Two carrot tops, buried within the dirt and watered every several days to mimic rainwater, had completely decomposed.
It was an experiment the teachers could easily recreate in their classrooms, along with a lesson on garbage decomposition and a discussion of how methane gas is turned into electricity at nearby landfills.
The 56 Valley teachers spent the morning visiting four renewable-energy sites operated by Salt River Project, gleaning information and exploring possible field-trip sites for future lessons.
Diane Hagenson, a Sonoma Ranch Elementary fourth-grade teacher, said what she's learning will tie in to the science unit she already teaches in her Gilbert classroom.
"I'm looking for new projects and new extensions of learning," Hagenson said. "I think this gives us ideas of ways to challenge our gifted students."
The field trips were part of a four-day workshop for the elementary, junior high and high school teachers to learn more about global climate change and renewable energy. The second annual "Global Climate Change in the Southwest: An Academy for Educators," was hosted by SRP and the Arizona Foundation for Resource Education.
Dawn Koberstein, a consultant with the foundation and the math facilitator at Chandler's Frye Elementary School, said the goal is to leave teachers with a better understanding of global climate change and its impact on the environment.
"It starts by teaching children because they are our future," Koberstein said. "The kids go home and tell their parents. That's where change happens. It's better to start young."
The first stop Wednesday was the Tri-Cities Landfill Generating Facility off state Route 87, also known as the Beeline Highway, in Scottsdale. The 4,000-kilowatt power plant is fueled by methane gas generated at the closed landfill.
The teachers visited the control room and learned how the methane gas is collected through 160 wells, piped into a power generation facility, and used to fuel internal combustion engines to send the energy to the power grid system. About 2,000 Valley homes are powered by this facility, said Joel Dickinson, an engineer in SRP's sustainability initiatives and technologies department.
At the Rogers Solar Park, off Lazona Drive and University Drive in Mesa, the teachers were given small solar panels to connect and try to light a small light bulb.
The teachers toured the $28 million, 400-kilowatt facility of photovoltaic power systems that use the sun to run 800 homes, Dickinson said.
The solar thermal cooling system, built nine years ago to cool a building at the Papago National Guard Armory in Phoenix, showed teachers an alternative to a traditional 10-ton air conditioning unit.
The final stop was Arizona Falls, the first hydroelectric plant in the state rebuilt in 2003 off a canal on Indian School Road in east Phoenix. The 750-kilowatt public facility, which uses water to power about 150 homes, was designed as a "nice gathering area," Dickinson said.
The teachers were handed maps of the Phoenix area water supply and given examples of how students can trace how water travels to their school, from the watershed to the tap.
After the workshop, which ends Friday, teachers will walk away with binders of activities and information, a hand generator for classroom experiments and lots of ideas to bring to their classes.
John Jung, a Mesa High School environmental science and geometry teacher, said he was looking for activities that will get his kids energized.
"I always felt environmental education should be required," Jung said. "We're at a tipping point of where we are with our species."