Which method would impress a second-grader more?

If you’re a typical youngster, or maybe a typical adult, you’d rather see a geyser of cola spew out of the bottle.

That was one of many activities that took place during this year’s Summer College for Kids, which, as in previous years, has been taking place at the Seaborg Mathematics and Science Center at Northern Michigan University.

Youngsters of various grade levels take mini-courses in morning and afternoon sessions, including “The Best of Bugs” in which kids learn about insect pollination; “Awesome Ozobots,” which features miniature robots; and “Let’s Get Down to Business” in which economics is the main topic.

Siggi Johnson, 7, mixes cranberry juice and baking soda to get a chemical reaction. The activity took place during the Summer College for Kids at the Seaborg Mathematics and Science Center. (Journal photo by Christie Bleck)

The STEM curricula has been involving into a STEAM curricula.

“They’re just enrichment courses in the area of science, technology, engineering, mathematics,” said Amy Burley, Summer College for Kids coordinator, “and recently we’ve been integrating some of the arts. We have a class that did some mindfulness activities, so it’s kind of expanding.”

Kids can explore on their own in the summer, but having trained instructors guide them probably is a more efficient way of getting them to get more out of the hands-on activities.

“If they don’t keep learning in the summer, they’re going to lose some of the things they’ve already done during the regular school year,” Burley said.

“I think the format that we kind of do it in with our teachers here really makes it fun and engaging, so it keeps them excited about learning in school.”

Teachers, most of whom are local, are paid stipends for their time.

One of the instructors, though, came from Minnesota.

Carissa Moe, who hailed from the Twin Cities, taught the “Mad Scientists” class for grades 2-3 during the July 8-12 session, which included the Mentos-pop demonstration on July 10.

“We’re going to do other experiments with milk and vinegar and baking soda, seeing all the different types of reactions,” Moe said

The Mentos activity was one of the most spectacular.

Moe took the youngsters outside — a good move considering the activity was on the sticky and messy side — where she dropped Mentos into bottles of cola, root beer, lemon-lime pop and orange pop.

As soon as the Mentos mint hit the liquid, the carbon dioxide formed more bubbles in the tiny pores found over the Mentos surface. As the Mentos sank to the bottom of the bottle, an eruptive blast occurred when the carbon dioxide was released and broke free, taking a lot of the pop with it.

The experiment wasn’t just about viewing the results but learning about the science and the process that went into it. So, before she performed the experiment, Moe got the youngsters thinking about various scenarios. Would the Mentos explode with all the kinds of pop? Would it take more than one Mento to cause a reaction? What pop would cause the biggest explosion?

When they returned to the classroom, they measured the amount left of each type of pop to determine which had the biggest explosions. The results were: 3.5 cups for cola and lemon-lime, and 2.25 cups for root beer and orange.

Moe, however, pointed out one mitigating factor: the root beer and orange bottles had been shaken before the experiment.

One of the students, 7-year-old Blake Sell, said the experiment resembled “an atomic bomb.”

Another experiment involved the students’ writing messages in invisible ink with lemon juice, apple juice, vinegar, and baking soda and water. When the papers were held to a heat source, the messages would appear.

It turned out the messages using the baking soda mixture showed up the fastest.

In yet another experiment, the students mixed acids and bases — two things needed for a reaction. When the acidic cranberry juice and baking soda, a base, were mixed, the resulting liquid fizzed, with the color changing to black.

The baking soda, Moe explained, neutralized the cranberry juice. However, when lemon juice, an acid, was added, the color returned to its original hue.

This week’s final session is to include classes such as “Star Wars Maker Lab” that allows fourth- and fifth-graders to stir up some “Jabba the Hutt slime, and “Design with Literature” in which kids in kindergarten and first grade can design STEM projects based on picture books.

Christie Bleck can be reached at 906-228-2500, ext. 250.