My last surviving grandparent, chemist Ernie Lewis, died last night at age 91. Granddad’s death had been imminent for a couple of weeks, and I’m not as sad to see him finally go as I’d been to watch him slowly slip away over these past few years.

Since we didn’t travel anywhere or host anyone for Thanksgiving, I’ve had plenty of time today for contemplation, and that’s one of many things I’ve got to be thankful for this year. Even though Granddad lived in Wilmington, Delaware, while I was growing up in Northeast Texas, I saw him often enough to accumulate a good number of memories for me to smile about today.

During one grandparental visit while I was a teenager, I was sitting on my bed doing nothing — possibly listening to the White Album, but that’s it. Granddad poked his head into my room and saw an opportunity to correct a likely deficiency in my education. “Do you know how a seismograph works?” he asked. I didn’t. He drew me a diagram.

After I was married and living near Austin, he came for a visit, and the two of us made a road trip to the brewery in Shiner, Texas. I mentioned that he was a chemist, right? Well, at the end of our tour of the mash vessels, brew kettles and storage tanks and the layman’s overview of the brewing process, the bright-eyed young tour guide asked if she had answered all of our group’s questions. “I think you’ve given us a bunch of gobbledygook,” Granddad replied. Mincing words — even when it might have spared unnecessarily hurt feelings — was not one of his talents, but I loved him all the same.

I think Granddad had been expecting to seriously learn about brewing, because he was — more than anything — a learner. Relatively late in life, he put a lot of his brainpower into learning Spanish, but he also took courses in his 70s and 80s about opera, human sexuality, and anything else that struck him as interesting. During a slide show celebrating his 80th or 85th birthday, I found out that he’d once had his pilot’s license, which — considering he’d never mentioned it — clearly was not as remarkable to him as it was to me. I absolutely loved buying nonfiction books for him, because I never had to worry about sticking to subjects he was already interested in.

But the memories of Granddad that most define what he meant to me are centered around a couple of adventures he and I went on during my teens. In early spring of 1985, he and I sat at my kitchen table surrounded by maps, guide books, and travel brochures. That June, he would be taking me and my cousin Justin on a month-long road trip, and he made sure I was involved up to my 13-year-old elbows in planning the thing.

Granddad could have just said, “Here’s where we’ll be going and what we’ll be seeing,” and our destinations and activities alone would probably have been plenty memorable. But because I had such a big role in determining what those destinations and activities would be, they turned out to be that much more so.

During that month, we hit Disneyland and Lake Pend Oreille, Sea World and Wall Drug, White Sands and Banff. Oh, and the Grand Canyon, Yosemite, and Yellowstone. Justin and I had the honor of being with Granddad when he crossed into his 50th state, North Dakota. He took us to a show in Las Vegas, but — since we were 13 and 10 — that show was the then-current theatrical release, Goonies. Having recently rewatched part of Goonies as an adult, I can finally appreciate his sacrifice.

The second trip came three years later, in March 1988. I had spent the week before spring break at a scholastic journalism conference in Washington, DC, and since I was already near Wilmington and had a free week, I got to enjoy a long solo visit with my grandparents. During my stay, Granddad and I made a day trip to New York City. The plan was to drive most of the way, and then take the train in from Newark. That was our plan, anyway. His plan had one additional detail.

As soon as we got onto the New Jersey Turnpike, we stopped for a bit at a rest area. When we got back to his Pontiac, Granddad asked me if I wanted to drive. I was a 16-year-old Texan with maybe one interstate trip to Dallas under my belt. It was morning rush hour on the New Jersey Turnpike. And my grandfather wanted to know if I wanted to drive?

What I wanted, even more than safety, was not to look like a weenie in front of Granddad, and so I drove, and we survived. On the subway — back when the car decor was still Modern Graffiti — I proudly wore my blue and gold journalism-contest letter jacket with a big Texas-shaped patch. (So much for safety-mindedness and not looking like a weenie.) Granddad showed me around his old haunts on the Columbia campus, and he took my picture while I struck my most sober pose at the Strawberry Fields memorial in Central Park.

But the highlight of that day was when my 71-year-old Republican man-of-science grandfather took my interests totally seriously and went with me to the editorial offices of Rolling Stone. We asked for a tour. They didn’t give tours, or maybe no one had ever asked for one. The combination of the letter jacket and the old man must have clued them in to just how serious I was, because I got a tour. Five years later, when I received an unpaid internship at Rolling Stone, it was a check from my grandparents that enabled me to accept the opportunity.

That career path turned out not to be the right one, but in children’s writing I finally found one that offers the joy and satisfaction that Granddad got out of his four-plus decades in the chemistry business. I loved telling Granddad about the subjects I was tackling and the progress of my projects, especially when I finally sold my manuscript about two of his contemporaries — one, a chemist — who changed the way the world looks.

I’m sorry that Granddad won’t get to read that book. I think he would have liked it. After all, the subject — daylight fluorescence — is something he knew nothing about.