Aberdeen Proving Ground (APG) hosted about 650 children for its annual Earth Day celebration that was held at the Aberdeen Youth Services Center, Apr. 26. Many of the students were from Harford and Cecil County public schools.U.S. Army Research Laboratory (ARL) scientists and engineers; Dr. Lisa Marvel, Terri Racine, Jerry Chaney, Megan Lynch, and Dr. Sandy Young, along with volunteers Al Marvel, Ann Bornstein, and Neelam Mehta, staffed four activities: environmental snap circuits, ultraviolet (UV) bracelets, oil contamination in the environment and photosynthesis in a cup.When visiting the tables of the Marvels, students built environmental snap circuits and then took them outside into the daylight to check to see how they would operate."This is very awesome!" said one young visitor to Lisa Marvel after he tried out the snap circuit he built, which consisted of a solar panel, fan and meter.Lisa Marvel said the purpose of taking the circuit outside was to get enough energy from the sunlight to make the fan go. "We wanted to teach the kids about solar energy," she said.Small quarter page handouts were given to students describing the experiments to allow them to discuss the experiments later with their parents. The handout for Snap Circuit Green discusses an easytouse, hands-on learning experience and educates on environmentally friendly energy sources and thinking green.Students attending the Earth Day celebration also participated in the photosynthesis in a cup experiment. In photosynthesis, solar energy is converted to chemical energy. The chemical energy is stored in the form of glucose (sugar). Carbon dioxide, water and sunlight are used to produce glucose, oxygen and water.Young and Lynch taught the process to the students using green leaf spinach, a mild baking soda solution, a vacuum process using a plastic syringe, and work lights to expedite the process.The UV bracelets and necklaces were a huge hit among the students. The purpose of this activity was to teach about the danger that exists outdoors that you can't see with the human eye -- the danger of ultraviolet or UV radiation. Students learned that by wearing sunscreen, hats, and sunglasses, that you can help protect yourself by using these items when you are outside. They also learned how UV radiation can be useful as it makes flowers look like targets to attract bees for pollination."Today we used UV sensitive beads and recycled plastic shopping bags to make UV radiation detectors," said Racine. "The children were fascinated to see the beads change color with the ultraviolet flashlight."The final ARL activity educated students about oil slick/pollution. When an oil spill occurs, oil sticks to fur and feathers impairing waterproofing and insulation and exposing the animal's sensitive skin to extremes in temperature. Animals instinctively try to get the oil off of themselves, which results in the animal ingesting oil and causing damage to its internal organs.The children were able to visually see rescued birds that were brought to the event by Scales and Tales. Two Naturalists from Patapsco Valley State Park brought in a turkey vulture (hawk) and an owl."The success of the event was in no small part due to the collaboration between the APG STEM [science, technology, engineering, mathematics] group [ARL, U.S. Army Communications-Electronics Research Development and Engineering Center (CERDEC), U.S. Army Edgewood Chemical Biological Center (ECBC), U.S. Army Research and Development Command (RDECOM)] along with various Garrison groups and outside collaboration with the Maryland section of the American Chemical Society, Maryland master gardeners, the Edgewood LEAP [leadership, education, arts and play] program, Picerne Military Housing and Scales and Tales made for a fantastic experience for students, teachers and chaperones," said Young, ARL-APG STEM education outreach office. "Teachers were impressed by the wide-variety of activities for the students to do, the quality of the environmental lessons and the energy of the presenters."