Friction is your friend…. A climber rests easy in her knowledge of physics

by Stephanie Chasteen on November 11, 2010

I was recently offered the chance to do a guest post for Expand Outdoors (a local blogger’s site about how the outdoors can be a powerful force for life transformation).  So, what would I write it on?  The physics of climbing, of course.

Here is an excerpt of what I wrote for her site.  Or, read the whole post on Expand Outdoors.

On top of the third Flatiron, Boulder CO. Courtesy Brian Moore.

Some people watch TV to relax.  Some play Sudoku.   I’ve got my own form of mental Sudoku – I like solving puzzles on the rock.  Rock climbing gets me out of my head and into the “now” like nothing else.  Most climbers will tell you the same thing.  There is nothing but the moment, the hand placed on the hold, the tension in the shoulder, the push of the ankle, and the ground, sometimes a long way down.

But all the physical puzzles on the rock are also physics puzzles – the balance of force and friction, power and pressure.  As a physicist, the scientific side of climbing both intrigues me, and helps me have confidence in my ability to stay safely on this side of gravity.  While I’m certainly not calculating drag forces while I’m grunting my way around a difficult crag, I do have a certain amount of internal joy in seeing that, well, physics works.

In climbing, friction is certainly your friend.  We wear shoes with sticky rubber, and coat our hands with chalk.  All this is to increase the coefficient of friction – or how “sticky” something is.  We use the greek letter “mu” for friction.  The bigger mu is, the stickier it is, and the less likely it is to slide.  Sandpaper has a bigger mu than, say, grease.  Which brings us to the first (and probably only) terrible physics joke in this whole blog post (courtesy of Dr. Ted Hodapp):

A cat and a kitten are standing on a slanted roof.

The cat stays on but the kitten falls off.


Smaller “mew”.           (i.e., “mu”)


Want to read more?  And understand the picture below?  Read the whole post on Expand Outdoors.

Alcatraz Canyon (tough to escape!), Utah. Courtesy Brian Moore

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