Watch out for flying water balloons this Saturday.

Tau Beta Pi, the national engineering honor society, is hosting a catapult-building competition for high school students from surrounding areas.

The competition will start at 2 p.m. at the outdoor classroom next to the Iowa State University Cemetery, located north of campus.

Jeff Larson, Tau Beta Pi cabinet member, said six teams from area high schools will compete.

“Veishea brings in a lot of people to see the campus,” said Leann Faidley, cabinet member of Tau Beta Pi. “We want to try to get high school students interested in the engineering college.”

She said the teams have submitted reports detailing cost of materials, catapult specifications and safety factors.

The reports are “modeled from the type of report an engineer would write in industry,” said Faidley, senior in engineering science.

Building the catapult provides hands-on engineering experience and gives an opportunity for students to see physics in action, Larson said.

“It’s an opportunity for students to use their skills outside the classroom,” said Larson, senior in computer engineering.

This is the first and last time for the event, Faidley said.

“We won’t do the catapult competition again because we don’t want schools to use the same design,” she said.

Winners will be selected based on distance the water balloons fly and a report and diagram specifying how the catapult was constructed. The winner will receive a plaque, and all participants receive T-shirts.

The funding for the event came from a grant, called Greater Interest in Government, issued by the Tau Beta Pi national chapter, Faidley said.

“Grants are geared for TBP chapters to do some sort of community service,” she said.