“I found that clay worked the best,” Alyssa Killingsworth, 13, said as she explained her science experiment to the judge, who listened and jotted down notes on his clipboard.
Last week, Killingsworth joined 22 other seventh- and eighth-graders in Southside Christian School’s annual science fair. Three judges viewed the trifold presentations, which had to include a list of materials, a procedure, a hypothesis, results, a conclusion and a Biblical integration for their findings.
Inspired by archaeological digs beneath ash from a Mt. Vesuvius eruption in Pompey, Italy, eighth-grader Killingsworth had studied “How to Make an Archaeologist’s Life Easier.” Specifically, she wanted to know how to make the most accurate plaster castings.
When Mt. Vesuvius erupted, it buried stragglers leaving Pompey under feet of burning ash. When archaeologists discovered the remains, all that was left were imprints. In 2001, they started pouring plaster into the cavities and removing castings of people, footprints and other objects.
“I’ve always been very shocked by this,” Killingsworth said. “They were so smart to pour that in there instead of digging around them and destroying them.”
In her experiment, Killingsworth made beds of clay, sand and topsoil. She pressed objects like a rubber snake and other toys into the beds, “kind of like when you put a stamp in Play-Doh,” she said.
She removed the toys and poured plaster of Paris into the imprints. She let the plaster harden and pulled it out. Sand worked the worst, and clay worked the best. “It’s the most pliable,” she said.
Seventh-grader Zach Winterstein, 13, titled his project “How Accurate Can You Be?” He rounded up five of his friends and his dad and took their pulse at resting rate. Next, they all fired three rounds from a .22-caliber rifle into a target 20 yards away. Then they ran 25 yards and shot again. Then they ran 50 yards, shot, ran 75 yards, shot, ran 100 yards, shot.
Each time, he took their pulse for one minute. He also marked the bullet holes with different colors in order to study the accuracy later on.
Winterstein’s hypothesis was that people would shoot with less accuracy if their heart rate was up. After graphing the heart rates and comparing it to the accuracy of the shots, he found his answer:
“It turned out that it didn’t,” he said. “It turned out that they concentrated more because they knew they were being tested.”
A section in his report included the effect of exercise on the accuracy for Olympic biathlon competitors, who cross-country ski before shooting at targets.
“I learned that biathletes don’t have time to slow their heart rates, so they just have to practice shooting under pressure,” he said.
Seventh-grader Alyssa Stephenson, 13, tested five different disinfectants to see which one killed the most bacteria. One of the biggest-name brands “was actually the worst,” she found.
For her Biblical integration, she wrote: “God made man to have dominion over all things, as we see in Genesis 1:26. We are supposed to look after our world and the people around us. That includes helping others by testing disinfectants to see which one kills more bacteria. If we didn’t have disinfectants, then there would be more sickness.”
Eighth-grader Rebecca Douthart, 14, named her science experiment “Fuel or Fatal?” and tested the effects of oil on plants.
“I found out that even a light oil such as motor oil can kill a plant, so we should be more careful with runoff, especially from parking lots,” she said.