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Physics/My crate shrank


Hi Dr. Nelson,
A year ago, I made a crate out of wood and cardboard (wood frame, thick cardboard outside) to ship my skis to Utah. Now, this year, I wanted to use it to store my skis, and my crate had shrunken six inches!
I sincerely wish this was a prank, but it isn't. I measured, and my skis stayed the same length. The crate shrank six inches. The wood was cured and it is 10 years old. The cardboard did not buckle or anything, and the tape didn't move. It was as if it was originally built six inches shorter than it actually was built. Why did this happen?

Fibrous materials are complex, and for a detailed analysis you would need to get in contact with someone who's more of an expert on materials science and perhaps even on wood, not a physicist.  I can see that if it were exposed to some condition (extreme heat and water vapor being the two most likely candidates) that it could shrink by a few percent.  That's enough.  Fibrous materials tend to do this over time, if something can cause the fibers that comprise the materials to kink and twist up.


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Dr. Stephen O. Nelson


I can answer most basic physics questions, physics questions about science fiction and everyday observations of physics, etc. I'm also usually good for science fair advice (I'm the regional science fair director). I do not answer homework problems. I will occasionally point out where a homework solution went wrong, though. I'm usually good at explaining odd observations that seem counterintuitive, energy science, nuclear physics, nuclear astrophysics, and alternative theories of physics are my specialties.


I was a physics professor at the University of Texas of the Permian Basin, research in nuclear technology and nuclear astrophysics. My travelling science show saw over 20,000 students of all ages. I taught physics, nuclear chemistry, radiation safety, vacuum technology, and answer tons of questions as I tour schools encouraging students to consider careers in science. I moved on to a non-academic job with more research just recently.

Ph. D. from Duke University in physics, research in nuclear astrophysics reactions, gamma-ray astronomy technology, and advanced nuclear reactors.

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