SPENCER GLACIER, Alaska — Sure, seeing is believing, but sometimes seeing leaves you in disbelief. That happened to me while kayaking among icebergs here recently, as the landscape transformed before my eyes, Amy Harder writes.

• Why it matters: I began the kayaking excursion certain of what I was seeing. I ended it with my mind blown — by the sheer scale of nature and by how much perspectives can change.

🌊 State of play: The glacial lake here, not far from Anchorage, is accessible only by the Alaska Railroad train.

• The glacier and lake looked rather small as we approached it on foot with our kayaks in tow. I felt a tinge of disappointment.
• I figured the glacier was maybe a half-mile away, with dainty-looking icebergs in between us. Then our guide told us it was 2 miles away. No way, I said, as confident as ever.

"I'm fine being wrong," the guide joked with equal parts politeness and sarcasm.

• Once we got into the water and started paddling, my entire field of vision changed dramatically in an extreme manifestation of "motion parallax." I soon realized how small I was, how big those icebergs were and how far away that glacier really was.

🏔️ How it works: "Motion parallax" is a common phenomenon we experience when moving. It's why trees whiz past us while driving but mountains in the distance barely seem to move. Glacial landscapes can put this phenomenon — and our struggles to perceive depth and scale — on steroids.

• From shore, nearly everything in my field of vision was enormous — mountains, ice, water — leaving me with few familiar visual cues to grasp just how big or far away anything really was.

When we started paddling, movement — and our kayaks themselves — gave my brain new information.

• Despite paddling quite a ways, the glacier remained stubbornly distant, while those dainty-looking icebergs grew to the size of cars and small buildings.

👀 The big picture: It was strangely empowering to be so wrong. I was confident in what I was seeing, and then my guide — and eventually my own eyes — showed me otherwise.

• That sense of wonder has lingered, making me curious about what else I might be so sure about — and wrong about.
• It was also a reminder that, from a distance, people and problems can look smaller, simpler and more obvious than they really are. Get closer, learn more and add context, and the picture can change dramatically.

The bottom line: Sometimes changing your mind isn't a sign that you saw things wrong. It's a sign that you're finally seeing more.

• Share this story.

It's National Grandparents Day on Sunday, a chance to celebrate the unique grandparent-grandchild bond.

• For our young Finish Line readers: Here's a list, via Time Magazine, of 12 questions to ask your grandparent — or another source of wisdom in your life, like an aunt, uncle, godparent, teacher or coach.

Happy weekend!