I am afraid of heights.

I remember the day this phobia enveloped me. I was watching a basketball game high inside Thompson-Boling Arena at the University of Tennessee at Knoxville when I was overcome with dread — as if, at any moment, I could fall head-first, screaming like a little girl, to an ugly death below.

Applying the laws of physics, I would have actually fallen only three feet into the lap of a geography teacher from Alcoa. But the tortured mind of an acute acrophobe — Latin for “flying zamboni” — is not interested in true facts. I remember gripping the armrests on my seat until the veins on the back of my hands bulged out like purple ropes.

From that day forward, I avoided high places. For example, I only visit Rock City Gardens at night. Also, I don’t like walking on the second level at Hamilton Place mall.

Last Sunday, my fear of heights collided with my duty as a daddy. My 6-year-old son won free passes at school to Lake Winnepesaukah: official park motto, “Come On, Get Happy!” (Does the Partridge family know about this? Seriously.)

Anyway, I gathered my courage. The last time my son and I went to Lake Winnie he was 4 years old and his favorite ride was Kiddie Boats. This time, I thought we might actually work our way up to the Ferris wheel. I figured I could grit my teeth and close my eyes for two minutes.

So, with a bit of swagger last Sunday, I climbed aboard the big wheel.

“What’s happening now, Son?” I said 30 seconds later with closed eyes and clenched teeth.

“We’ve stopped at the tippy top,” he said, rocking the seat back and forth enthusiastically.

“Stop it!” I shouted, peering out of slit eyes into the murky depths of Lake Winnepesaukah — Cherokee for “Lake of the Giant Carp.”

I escaped the Ferris wheel with my heart in my throat, but my son immediately began dragging me by the hand to the back of the amusement park, toward the Cannon Ball roller coaster. The park’s signature ride features a vertical drop of 70 feet with the cars reaching speeds of 50 mph.

“I want to ride that,” my son said, pointing up to the Cannon Ball.

“Oh, no, you don’t,” I said.

Panicked, I steered him over to the tamer-looking roller coaster called the Wild Lightnin’. Still, I had my fingers crossed that he wouldn’t meet the 48-inch height requirement.

“He’s good,” said the ride operator agreeably as we walked up the ramp.

“No, he is NOT good,” I said, pressing down on his head. “He is only 47 inches tall.”

Quickly, the boy escaped from my grip, removed his Red Sox cap and parked himself under the 48-inch stripe. He opened his eyes widely apparently thinking this would push his head higher.

“See,” the operator said. “Told you he was good.”

I grumbled as we boarded the Wild Lightnin’, which spins and bucks like a rodeo animal.

From that moment, there was no turning back. The 49-inch boy put old Dad through the ringer. In the next two hours we rode the Wild Lightnin’ five times, the Wave Swinger four times and the gut-churning Pirate Ship once. Four times we even ventured onto the dreaded Cannon Ball.

The last ride on the Cannon Ball, I got brave and showed the boy how to raise his hands on the dips.

Later, at home, I felt like bragging a little.

“Buddy,” I said. “Tell your Mommy there what I showed you how to do on the Cannon Ball.”

“Really?” he said.

“Yeah,” I said. “Go ahead. Tell her what I showed you.”

“Mommy,” he said, “Daddy showed me how to scream like a LIT-TLE girl.”