The Science of Snow Caves
Valentine's Day 2007 gave the gift many students on campus had been waiting for all winter: a huge snowstorm, along with a (bonus) cancellation of classes. Two days later, students in Natural Sciences Professor Nick Baer's Interactions in Ecology (BIO/CES 107) class were finally able conduct an experiment in deep snow on how animalsincluding humanssurvive in harsh winter environments.
On a sunny yet frigid and windy morning, the students headed out of the Ivey Science Center and into the snow with shovels and a few temperature data loggers in hand. Within an hour, they had built two snow caves, one large, one small, and placed the gauges in each, as well as in the ambient air, to measure the temperature of these environments.
A few students crawled into each cave to record temperatures over the next 45 minutes, which were then downloaded into spreadsheets that the whole class could graph and analyze. While the outside temperature was officially 20 degrees fahrenheit with much colder wind chills, the cave temperatures hovered around 32 degrees, without the icy wind.
The purpose of the snow cave exercise was to quantify what Bernd Heinrich explains in his book Winter World as the insulation snow provides for many organisms surviving winters in New England, says Professor Baer. The goal is also to have students hone their analytical and graphical skills and relate their experiment to our course discussions and readings about animal adaptations and survival in the winter landscape.
Snow as Insulation
In New England, rodents spend most of the winter under the snow, an area called the subnivian zone, where they can forage for food and stay warm. Some birds, such as the ruffed grouse, take shelter under the snow during harsh winter storms or especially cold conditions, according to Professor Baer.
John Bristol '09, a psychology major with a minor in biology, worked with Alex Azodi and Andrew Baker to construct the larger snow cave. After spending time in the cave, Bristol says the experiment showed him that snow serves as an excellent insulator.
It allowed us to see how the creatures living in this climate are able to survive the harsh New England winters, he says. This greatly affirmed what we had already read in Winter World by Bernd Heinrich. It was very similar to the methods used by organisms in the area.
Zachary Irish '08, a history, society and culture major, pitched in to clear away snow from outside the caves. The snow cave provides a great source of shelter from the cold. The temperature difference (between the ambient air and inside the caves) was amazing, he said. The caves were much warmer but the two caves, of very different sizes, were pretty consistent temperatures.
Experiments such as this one provide a good training ground for students in scientific methods, according to Professor Baer.
"It's an opportunity for students to develop a question and then create an exercise that will help them find the answer. They go through the scientific method of collecting, analyzing and interpreting the data," he explains. "In a short period of time, students were able to learn some important ecological concepts, while experiencing firsthand how small animals survive in winter."
-Kimberly Swick Slover