STOCKTON, MO. ? Arlene Kardoes belongs to a garden club and a book club. She is a retired nurse practitioner, and in her spare time, she likes to visit her four children, 19 grandchildren and two great-grandchildren, who are scattered across the country.

And three or four times a year, the 70-year-old Kardoes straps a 20-pound air tank to her back and descends 50 feet under water.

This grandma is a scuba diver.

No one in her family, including her husband, has ever accompanied her on a dive. But everyone, except her husband, expresses an interest in learning. Work, school, money — these are among the excuses her family gives for not taking the plunge with her. So when Kardoes’ 13-year-old grandson, Michael Sitzman, visited Missouri during his summer vacation, he wasn’t expecting the surprise grandma had for him.

Kardoes, who lives in Stockton, took her grandson to Joplin for an introductory scuba lesson at Calypso Scuba and Ski, which is owned by her first scuba teacher, Valerie Earl. Kardoes came to Earl to learn scuba after a trip to Hawaii. During the vacation, she had gone snorkeling, which is basically underwater swimming with a mask, snorkel and fins. While she had to stay on the surface, Kardoes envied the divers swimming deep under the water for long periods of time.

“I wanted to know what was going on down there,” she said.

Earl said Kardoes’ route to scuba was a common one.

“Most people are like Arlene. They go on a cruise or vacation and try snorkeling,” Earl said. “Scuba is easier.”

Over the past few decades, scuba has evolved from a sport only tall, muscular men could do (because the equipment was so heavy and made to fit a larger size), into a sport accessible to almost anyone. With today’s equipment, Earl said it had moved beyond “what I call the dark ages of diving.”

Arlene Kardoes, 70, Stockton, Mo., checks her scuba gear before going into the pool at Calypso Scuba and Ski in Joplin, Mo. Kardoes became interested in scuba diving after a trip to Hawaii.

Kardoes estimates she has gone on about 180 dives. Hawaii, Cozumel, the Caymans. This month, she plans to travel again to the Cayman Islands. Once again, her husband will not be joining her.

“He does not like water,” Kardoes said. “He likes to fish — from shore.”

She explained that for a couple years during the war, her husband was stationed on an island in the Pacific “just long enough for the runway.”

She said her husband kids her about diving.

“His favorite saying is, ‘Anybody who would jump off a perfectly good boat has got to be out of their mind,”‘ Kardoes said.

Arlene Kardoes, right, and scuba instructor Michelle Jones, back to camera, help Kardoes' grandson, Michael Sitzman, 13, during his first scuba lesson at Calypso Scuba and Ski in Joplin, Mo.

Her grandchildren think it’s pretty cool to have a scuba-diving grandma, Kardoes said, though she hasn’t been able to give them their own firsthand experience with diving.

Sporting toe rings and Adidas flip-flops, she said, “I’ve got 19 grandkids; I can’t put them all through training.”

But when her grandson Michael Sitzman arrived, Kardoes told him that he would be diving with grandma in the Calypso pool.

After watching an intro-to-scuba video and receiving poolside safety instruction, it was finally time for grandma and grandson to get changed into underwater gear.

Michael entered the pool room in his swimming trunks, Kardoes in her wetsuit. Calypso owner Valerie Earl led Michael to the shallow end. Kardoes took a stride jump into the deep end. Only the roaming bubbles at the surface of the pool gave away her location. Toward the end of the hour, Michael was ready for some deep-end swimming with his grandma.

When the two exited the pool, both a little reluctant to leave the water, Michael had gained a new appreciation for his grandma’s hobby.

“It was awesome,” he said.