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Re: [Phys-L] why ice is so slippery

I agree it's a nice article, but it's disappointing that the author makes the pressure claim right before the Veritasium video, and then ignores his own observation just after the video that the pressure argument is insufficient. He states you'd have to be an incredibly massive skater to melt ice, but ignores the need for proportionally massive hanging weights on the ice block wire.

To its credit, the Veritasium video never refers to pressure, attempts to normalize the pressure aspects by selecting the same size cutting lines, and speculates, in the style to which Derek the videographer is accustomed, about thermal conductivity.

I've not tried very hard with this experiment but I'll say that it's a bit more difficult to do than it might appear. The times I've tried it, the quality of the ice block I make seems to be a major factor. Without a cold environment of course, the ice begins melting, and has always been of a quality to just break off after a period of time, long before any real "cutting" was evident. The video shows a "nice" block of ice that is well-supported. It's also not a good classroom demo – the time-lapsed video is for a reason!

Stefan Jeglinski

On 2/18/18 5:27 AM, Jeffrey Schnick wrote:
I thought the wire cutting its way through the ice by creating a high pressure zone at the bottom of the wire had been debunked and that it is heat conducted along the wire that does the melting.

-----Original Message-----
From: Phys-l [] On Behalf Of John Denker via Phys-l
Sent: Saturday, February 17, 2018 3:08 PM
To: Forum for Physics Educators
Cc: John Denker
Subject: [Phys-L] why ice is so slippery

Hi --

A seasonal and topical bit of condensed-matter physics.
Aimed at a general audience, but contains some hard numbers and makes a number of good points. Contains links to primary sources.

Brian Resnick
"The surprising science of why ice is so slippery"

TL;DR: There's an ultra-thin surface layer that isn't really frozen.
Forum for Physics Educators
Forum for Physics Educators