Molten glass - Mark Interrante - from NY Times

Molten glass - Mark Interrante - from NY Times

This is an addendum to my earlier (and popular) post about whether or not glass is a liquid.  If you haven’t read the previous post, the crux of the myth is that many of us are taught in science class that glass is a veeerry slow flowing liquid, and that’s why old windows are thicker on the bottom than the top.  News flash — actually you can find old windows that are thicker on the top than the bottom because it’s just an artifact of how glass windows were poured back in ye olde days.  But that doesn’t mean that glass is a simple thing.

A few months ago there was a great article in the New York Times Science section called “The Nature of Glass remains Anything But Clear“.  This very nice article about glass talks about how — even if it’s not a liquid — it’s a pretty complicated thing. “The arrangement of atoms and molecules in glass is actually indistinguishable from a liquid,” it says Solids tend to have atoms arranged in nice little tinker-toy stacks, whereas atoms in liquids aren’t so organized, more like someone threw the tinker toys across the floor in a rage, which is why they can flow.  The atoms in glass are more jumbled than organized.  So how come glass is so strikingly hard if its atoms don’t have a rigid order?

From the article:

“When cooled, a liquid either freezes, as water does into ice, or it does not freeze and forms a glass instead. In freezing… the molecules line up next to and on top of one another in a simple, neat crystal pattern. When a liquid solidifies into a glass, this organized stacking is nowhere to be found. Instead the molecules just move slower and slower and slower, until they are effectively not moving at all, trapped in a strange state between liquid and solid. .. This glass transition does not occur at a single, well-defined temperature; the slower the cooling, the lower the transition temperature. … By contrast, water, cooled quickly or cooled slowly, consistently crystalizes to the same ice structure at 32 degrees Fahrenheit.”

The reason glass forms is still a hot topic, with many competing theories.

There have been several posts around the blogosphere of late regarding a report from journalist Steven Goddard that the arctic sea ice isn’t melting as quickly as we thought. In particular he was calling into question the validity of the data reported from the National Snow and Ice Data Center (NSIDC) in Boulder, Colorado — I’ve included that graph below.

However, his analysis was not well-founded, and he’s since admitted his mistake. The Island of Doubt has posted a nice summary of what was wrong with his arguments. They write:

Goddard’s article is rife with scientific errors and evidence of his lack of familiarity with the science. His main argument, that the ice area up there is 30% larger than last year, not just 10%, is the product of the fact that Goddard based his story on his own analysis of images from the NSIDC and other sources. That analysis… consisted entirely of counting white pixels…. It turns out that Goddard got confused because he didn’t take into account map-projection distortion differences between competing images.

Once that little problem is dispensed with, it turns out that there is no discrepancy, the arctic is melting faster than normal, and may yet break last year’s record. Or not. Even if Goddard had been right, though, that says nothing about long-term trends. The point is, as Goddard proved, if you’re going to argue that an entire field of scientists got it wrong, you really should know something about the subject.

To Goddard’s credit, though, he admitted his mistake.

Sadly, the story has already started to make its way around the internet. So, just like myths like polar bear fur being a fiber optic (it’s not), or cats which grow wings (they don’t) it may be hard to get this one to go away. Why is it so much easier to spread rumors that something false is true than to fix the problem by telling people that something they think is true is actually false?  It’s made worse by the fact that some folks want to have fodder to fuel denialist claims, so they don’t have a lot of reason to correct erroneous information.

Deltoid also blogs about Goddard’s article here.