SYKESVILLE - When confronted with a booby trap, Master Sgt. Bill Yohn brought out an unusual tool to show where a tripwire was hidden in Millard Cooper Park: silly string.

Yohn had Owen Pruitt, 10, from Sykesville, assist him as he uncovered three booby traps he set up in the park for the Sykesville Gatehouse Museum's event titled "The Afghanistan Campaign: A Soldier's Perspective."

He showed how to identify a tripwire, and showed how a punji pit was made. In the Vietnam War, the Viet Cong would sharpen bamboo sticks and hide them in a hole covered by grass and leaves, Yohn explained.

When a soldier would step in it, they would be injured by the spike, he said, which would take a few soldiers out of battle in order to send the injured soldier back to the base.

Yohn has 27 years of experience in the Army, and spent a year between 2004 and 2005 in Iraq. He was injured on the job, and now has titanium rods and screws in his spine.

Even though Yohn was injured, he chose to finish out his tour as the second highest non-commissioned officer in his unit.

"I told them the only way I was going home [was] if they carried me out. I wasn't leaving just because I was injured," Yohn said.

For his event, Yohn brought materials from the Army to explain camouflaging techniques and the evolution of weaponry.

Dr. Mark Fraser, the curator of the Sykesville Gatehouse Museum, asked Yohn to teach a class on his experience in Iraq to students while he worked at Faith Christian School. Yohn said this is the second class he's taught, and decided to add the booby trapping for Sunday afternoon's class.

"I just try to add to it each time," Yohn said.

Yohn also had his son Isaac hide among the trees in a ghillie suit, a dark textured uniform covered in different shades of green which resembles moss. It wasn't until Isaac moved twice that anyone in the audience was able to see a person hiding among the trees.

This was the third soldier who spoke in a summer series that Fraser organized primarily for children. The largest group was for an exhibit on bugs, with about 110 children.

Sunday's was the first event Pruitt attended, he said. Pruitt said he likes learning about different wars and the military. His favorite is learning about World War II because it's one of the easiest to understand.

Yohn said what he was most proud of in his experience, was that the unit he worked on did not lose a single soldier in Iraq. In March 2005, the death toll of U.S. troops in Iraq hit 1,500. A total of 4,409 service members lost their lives in Operation Iraqi Freedom, according to the Department of Defense.