Zipping his finger across the iPad and swiping the record button, 9-year-old Haley Ofoshhene gave his creature a voice: “I am an alien and I’m going to eat you.”

After that, every time the alien — which was surprisingly similar to a colorful, animated string mop head — moved across the screen, it repeated Haley’s words, in his voice.

“It wasn’t so easy at first,” said Ofoshhene, a third-grader at Mack Benn Jr. Elementary School. “At the beginning, it was hard to put your mind around … but they told us to never give up and ask questions.”

Ofoshhene was one of 20 Mack Benn first-, second- and third-graders selected to participate in last week’s PBS Kids Code-to-Learn after-school camp last week. The students were the test pilots for PBS’ new mobile app, ScratchJr. The free app, which is now available, is an introductory computer programming language that allows young children to use coding to create their own interactive stories and games, according to Angie Callahan, director of children’s services at WHRO.

Using a Verizon Foundation grant to teach students and teachers how to integrate coding into public schools, PBS Kids got WHRO — as well as two PBS stations in Las Vegas and Tacoma, Wash. — to run the camps. Students progressed from basic knowledge to more advanced programming skills over five days, with an on-site evaluation firm evaluating the camp to work out any final kinks.

WHRO also received funding to conduct professional development coding camps to elementary teachers this summer, Callahan said.

Mack Benn students excelled with ScratchJr, which taught students to snap together programming blocks to make characters move, dance, sing and jump, Callahan said.

“These kids are digital natives. They loved the app,” she said. “As soon as we showed them one command, they figured out how to do the others on their own.”

“It was fun because we got to program what characters do and how they move,” said third-grader Nathan DeWolfe.

That was also the appeal for Destiny Ireland, 9.

“I love it,” she said. “I got to create my own games and make my characters do whatever I want them to do.”