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Study finds chalk actually decreases friction


mythosgrl

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For all those chalk haters out there, this is for you:

 

http://www.ncbi.nlm.nih.gov/pubmed/11411778?ordinalpos=9&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum

 

Coating (chalk vs no chalk), dampness (water vs no water) and rock (sandstone, granite and slate) were manipulated. The results showed that chalk decreased the coefficient of friction.

 

The counter-intuitive effect of chalk appears to be caused by two independent factors. Magnesium carbonate dries the skin, decreasing its compliance and hence reducing the coefficient of friction. Secondly, magnesium carbonate creates a slippery granular layer.

 

We conclude that, to improve the coefficient of friction in rock climbing, an effort should be made to remove all particles of chalk; alternative methods for drying the fingers are preferable.

 

 

I am not arguing yay or nay for chalk (there are past threads for that if you want it), but I just thought it was interesting.

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Finally, water had no significant effect on the coefficient of friction.

 

tell that to someone who's greased out of a crack on a hot day.

 

And, why would "alternate methods for drying the fingers" be preferable, if water has "no significant effect on friction?"

 

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Finally, water had no significant effect on the coefficient of friction.

 

And, why would "alternate methods for drying the fingers" be preferable, if water has "no significant effect on friction?"

 

Oil (aka grease) is the problem, not water.

 

Perhaps that's why liquid chalk has a lot of isopropanol (rubbing alcohol).

 

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Hmm, that kinda makes sense I guess, but I thought sweat was mostly water.

 

However, if sweat is oily, then I wonder: chalk may lower the coefficient of friction, but does it lower it more than oily sweat does? It would seem not, since chalking seems to help. However, it doesn't seem like the study added a control for oil -- just water.

 

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I find water doesn't decrease friction on its own. If there is a bit of algea or other particles on the rock the water ir running on then you get slippery rock. Also, I know chalk decreases friction. Thats why we have little brushes to brush chalk off holds. To dry your hands you should dip in your chalk bag and then blow/clap to get all that excess chalk off your hands.

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For all those chalk haters out there, this is for you:

 

http://www.ncbi.nlm.nih.gov/pubmed/11411778?ordinalpos=9&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum

 

Coating (chalk vs no chalk), dampness (water vs no water) and rock (sandstone, granite and slate) were manipulated. The results showed that chalk decreased the coefficient of friction.

 

 

 

 

The counter-intuitive effect of chalk appears to be caused by two independent factors. Magnesium carbonate dries the skin, decreasing its compliance and hence reducing the coefficient of friction. Secondly, magnesium carbonate creates a slippery granular layer.

 

We conclude that, to improve the coefficient of friction in rock climbing, an effort should be made to remove all particles of chalk; alternative methods for drying the fingers are preferable.

 

 

I am not arguing yay or nay for chalk (there are past threads for that if you want it), but I just thought it was interesting.

 

 

 

Seems to be a small study done 7 years ago.

 

Probably doesn't model V15 or 5.15 very well.

 

Probably climbers would've noticed before now.

 

J. Sports Sci. not so hard to get published in - check Citation Index to see if this study had any connection to anything

 

It's already known that shoe rubber on bare rock isn't way more slippery when wet; skin could be the same deal

 

BUT mixing chalk with water, e.g. sweat, could lead to a variety of possibly contradictory effects on friction, depending on the proportions, and there are other substances in the mix which could be sources of variation, such as psychology, spiritual attunement to the rock (is that possible with the pebbles used in the study?), and shorts over polypro.

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Seems to be a small study done 7 years ago.

Probably climbers would've noticed before now.

J. Sports Sci. not so hard to get published in - check Citation Index to see if this study had any connection to anything

It's already known that shoe rubber on bare rock isn't way more slippery when wet; skin could be the same deal

 

What he said. What's more slippery - chalk or oil? Are there better alternatives while climbing? Sawdust? Charcoal? Silica powder?

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a small pouch of MEK, acetone or lacquer thinner would negate the chalk issue completely, if it's the oil that's the problem, plus all the compulsive bag-dippers would eventually die off, leaving the crags full of chalk free & less polished holds for the ultra traditionalist coalition. If you wanna try sawdust, I have tons, all types, u-haul.

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