Sunday, March 6, 2011

What's it like? Snow formation and analogies.

We don't understand something unless we understand what it's like. Looking for analogies is fundamental to making sense of the world and is therefore fundamental to what scientists do. Like the first entry, we'll again look to snow for analogous structures to things that we who teach Earth science often talk about, but don't often find within walking distance of our classroom doors.

The usefulness of analogies becomes more obvious, perhaps, when we get a bit further from home. As far as we know, no one has been to Mars, yet we have some pretty solid ideas about why the surface of Mars looks the way it does. The image below, and this link, link to, "A comprehensive image collection of rock breakdown features observed on boulders. This atlas is intended as a tool for planetary geoscientists and their students to assist in identifying surface features found on rocks on planetary surfaces."

It's loaded with images of rocks and the best scientific explanation of how they came to look the way that they do. What happens to rocks in one place is often a pretty good model for what happens to rocks somewhere else. Of course, that applies to a lot more than rocks. Looking for similarities while also being attentive to differences between situations applies to science and to life more generally. 

Analogy, and analogous features, was amongst the key points of the last post, Snow is a Rock Outcrop. For getting data on snow depths, there are almost certainly better places to go. The more important point was that having piles of snow in your schoolyard affords the opportunity to study something that is arguably a rock outcrop and certainly analogous to one. But, unlike most rock outcrops, it's right outside your classroom door (well, until last week, anyway)!

Since that post was written, a few ESPRIT listserv members have posted pictures of snow formations that are analogous to rock formations. (ESPRIT is an Earth science teacher listserv). I took a few too, and I invite folks to add more by linking to your pictures in the comments. Of course, we're about to be out of the snow season, so think of this as planting the seeds for things to do next winter.

This is also about looking; as in just paying attention to what is around you. Too often we forget to do that as I've written about on our Climate Change 101 Blog.

It's important to remember that analogies are never perfect -- and it's important to consider where the comparison fails. Thinking about that is a fine opportunity for critical thinking.

For the rest of the post, I'll simply share some photographs. They are groupings of snow formations with analogous rock formations, and it's really only a start and surely folks can find better pictures for some of these analogies. There are some more pictures here, and more were shared on the ESPRIT list.

Please feel free to add links to more relevant pictures in the comments.

A snow covered Adirondack stream. Photo by Michael Stark.

A snow covered Adirondack stream. Photo by Michael Stark.

Sulfur crystals around a volcanic vent, Hawaii. Photo by Allen MacFarlane.
Ice crystals near a sewer grate. Photo by Phil Medina.

Photo by Laura Rico-Beck.
Photo by Richard Gifford, via Flickr Commons.

Snow strata along a sidewalk after using a snowblower. Photo by Don Duggan-Haas.
A canyon wall. Photo by Frank Kehren, via Flickr.

Icicles within a snow bank. Photo by Don Duggan-Haas.
Stalactites and stalagmites, Natural Bridge Caverns, Texas. Photo by Don Duggan-Haas.
Stalactites, Natural Bridge Caverns, Texas. Photo by Don Duggan-Haas.  This photo is a combination of two exposures using HDRtist.

A weathered snowbank. Photo by Eric Fermann.
Weathered limestone in the Bahamas. Photo by Eric Fermann.

Frazil ice acts like lava in Yellowstone National Park.

Don Duggan-Haas


  1. Heathe Renyck had trouble logging in and asked me to post this for her:

    Nice post, Don. I also like how agents of weathering and erosion are sometimes enhanced by snow.

    This was taken after the Allegheny River's floodwaters receded (early winter):

  2. Some larger scale formations (in ice) are here:
    74 07'49.05"S, 127 17'56.99"W
    Check it out in Google Earth or Google Maps and then zoom out.
    Thanks, Laura!