At the Lawrence Hall of Science on Sunday, children built fake hands complete with bendable fingers, reminiscent of a cutting-edge, 3D-printed prosthetic made for 8-year-old Sophie Mercer in 2015.

Using cardboard, yarn, duct tape and straws, children modeled hands using principles based off of the prosthetic given to Mercer, who has symbrachydactyly, a condition that caused some of the fingers on her left hand to never fully develop. She received the prosthetic hand from the Center for Information Technology Research in the Interest of Society, or CITRIS, Invention Lab in 2015.

Michelle Rodriguez, the manager of public programs at the Lawrence Hall of Science, said a major goal of the “ingenuity challenge” was to potentially spark the children’s interest in engineering.

“We thought it would be a really neat idea to take something that folks on campus … are doing and be able to translate (it to) something that is accessible to our audience,” Rodriguez said.

When the children made the hands, they had to design and test them in order to get it right. Many children had to experiment and fiddle with their scraps of yarn and straws in order to get the fingers to bend properly.

According to Alexa Koenig, Mercer’s mother, Mercer cannot completely climb all the way across a monkey bars set yet, but she is waiting for another hand that can give her the durability required to successfully use the bars.

“It made her feel really special … as opposed to someone with limitations,” Alexa Koenig said about her daughter’s first prosthetic. “It gave her a newfound appreciation for what she can do without prosthetics.”

The CITRIS Invention Lab is developing a new model of the hand given to Mercer, according to Senior Lab Manager Chris Myers. Myers said the lab was in the process of “making a metal version that is much more reliable to support body weight and hanging from monkey bars.”

A water jet, which shoots a small stream of water at supersonic speeds, is used to cut the metal parts of the new prosthetic that are unable to be molded by a 3D printer.

Rodriguez said another goal of the challenge was to help children learn about the functions within their own hands. Simple diagrams of the human hand in skeletal form were on the table where the children built the hands.

In order to build empathy, the children looked at stories about other children who needed prosthetics, and they were supposed to consider whom they were making the hands for, rather than making something just because they enjoyed it.

“It’s nice to have kids learn that … it’s not just them going through the world,” Rodriguez said. “(The task) helps kids understand that there’s other folks out there with different needs from them and that they might be able to think about what those needs are.”