Expanding Rock Theory


We were on our way down from another peak conquered. Perhaps 2 miles to go of an 11 mile day. I caught my boot on a seemingly small rock. The ensuing tumble and a rather nice recovery, I thought, earned from Doug only a 7.9-and lots of laughter. I said how could this happen? Doug allowed that it truly seemed to be a problem as he'd experienced some small stubs too. Why?? I mean it could not be us--we were in well, not bad condition. So for the next remaining miles we discovered the real reason. From this discussion grew our first theory--the expanding rock theory. This theory explains the all to often occasion of stumbling on the way down after a long day

Key facts and observations:

  1. When one starts early in the morning as we do--it’s colder than it will be later normally.
  2. So on the way up, rocks to our touch feel colder than the surrounding ground.
  3. As the sun comes up the day gets warmer. Almost everyone knows this to be true.
  4. If you now touch the same rock lets say at 3 PM it feels significantly warmer than at 6 am.
  5. Now as we remembered our high school physics heated metal expands cold metal contracts. Elementary really.
  6. Consequently--as the day gets warmer--the rock expands.


Since the rock is bigger at 3 p.m. than at 6 am--one is much more likely to stumble on them on the way down. Consequently--the hiker is not to be blamed as being tired. It not their fault.

Theory--expanding rock:

A rock that is easily stepped over in the morning will be harder to step over in the afternoon--due to expansion due to the heat of the day.

Note: When we first relayed this theory to others, we were greeted with, well, laughter would be a polite word. For the disbeliever, we quote from national park sign on the Navajo Dome in the Capitol Reef National Park located in Utah. "Grain by grain infrequent showers and winter frost peck away at the white cliffs, dissolving the calcite cement.
Expanding in the noon glare, contracting in cool desert nights, the fine-grained Navajo sandstone erodes along it's original windcured shapes."

Who's laughing now??

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