Tanner Elementary fourth-grade students Carter Lee and Eva Menjavar toss magnets at Dayana Rosas' magnet toss project. Rosas said her teacher Misty Dindlebeck gave her the idea and she designed it.

Ping-pong balls bounced, rubber bands snapped and marbles rolled at the second annual Tanner Elementary School Science, Technology, Engineering and Math carnival on Monday and Tuesday.

Third-grade teachers Jessica Kent and Misty Dindlebeck started the STEM carnival last year to give students the opportunity to get their hands on science. It was such a hit with students and their family members, they decided to make it an annual event. This year, third-graders explored force, motion, gravity and magnetism by turning household trash into intricate science-based projects.

“You can’t really learn about force and motion from reading about it in a book,” Kent said. “It has to be on hands-on thing. They have to feel how magnets repel each other, and they have to discover how a rubber band can be the force that sends something into motion.”

Third-graders Caroline Brown and Sierra Baugher decided to build a dunk tank for the carnival. Their contraption — a towering thing constructed of cardboard paper towel rolls, paper plates and a recycled cake topper held together by masking tape — demonstrates the relationship between force, motion and gravity.

Brown and her co-creator Baugher are ready for the hordes of kindergartners anxious to try out their invention. Handing a ball to one of them, Brown explained force occurs when he throws the ball at the paper plate target and motion happens when the marble teeters off of its popsicle stick platform and drops down into the cake-topper tank. The kindergartner tosses the ball, hits the paper plate target and a marble rolls off the platform into the plastic tank, just as the two budding scientists had planned.

The dunk tank is just one of perhaps two dozen student-created projects at the carnival.

From one end of the room to the other, students stand behind their creations. There are marble runs, magnet tosses, catapult basketball games, magnetized mazes, ping-pong ball tosses and a wrecking ball swing, to name a few.

Jaden Williams and Emily Felipe Gonzales said the hardest part of designing their ball toss was keeping the plastic cups inside of it upright. They were making adjustments right up until the carnival started.

“That is part of what we are trying to teach them,” Kent said. “Engineering is a process of trial, error and redo. It is so hard to watch them fail, but it helps them learn from their mistakes and come up with a better plan.”

By the time parents and students from other grades started trying out Williams and Gonzales’ display, it was working like a charm.

Speaking to a group of fourth-graders, Williams explained their project “uses three science words — gravity, force and motion.”

“Doing the project helped me better understand what those things are,” Gonzales said. “Like how gravity pulls on things that are in motion.”

“I am so proud of what they have accomplished,” Dinglebeck said.

She was particularly impressed by her students’ responses to the AMSTI representatives who visited the carnival early Monday morning.

“They were able to answer their questions and use the terminology correctly,” she said. “It was really great to see the confidence they had in their projects.”