What does my knit sweater have in common with an avalanche?


Avalanches don’t just happen on mountains! Scientists use the concept of an “avalanche” to describe other phenomena that evolve in similar ways, such as forest fires, a stock market crash, or solar flares. In a recent paper released on arXiv, French physicists made the argument that knit fabrics also behave in this “avalanche” fashion. This makes them very useful for studying the properties of avalanche behavior, since a knit is much easier than a mountain to fit into a lab!

An important part of describing avalanches is the phrase “stick-slip.” Imagine you are trying to push a heavy box of antiques across the floor of your grandmother’s basement. You push it, but it is heavier than you expected, and it doesn’t move. As you push harder and harder, eventually the box slips, and you can now push it across the floor with less force than what was needed to make it move in the first place. The moment when the box stopped sticking and started slipping is called a stick-slip event. You could also describe the very beginning of an avalanche–the instant when the soil/snow/sand at the top of the mountain begins to slip–as a stick-slip event.

Knit fabrics are made of a network of threads; these physicists showed experimentally that stick-slip events happen at the intersections of these threads when the fabric is stretched. The threads can hold on to each other for a time, but eventually they slip; the first intersection to stretch causes the next intersection to stretch, and the knit network expands in an avalanche-like fashion. This is slightly unusual because avalanche behavior is not typically expected in things that are as neat and ordered as textile fabrics (think of how chaotic a landslide is!).

Hopefully this discovery helps improve our knowledge of avalanches, and systems that act like them!


Knits: an archetype of soft amorphous materials.  Samuel Poincloux, Mokhtar Adda-Bedia, Frédéric Lechenault

Photo by Dom J from Pexels 

Blood of Komodo dragons could provide antibiotic alternative

pexels-photo-42754(Note: I initially wrote this piece for a workshop at ComSciCon-PNW 2017)

In January of 2017, the Center for Disease Control and Prevention (CDC) published a much more frightening Morbidity and Mortality Weekly Report than usual: a woman in Nevada had perished from a bacterial infection that no antibiotic in America could fight. Doctors administered 26 different antibiotics to no avail.

“If we’re waiting for some sort of major signal that we need to attack this internationally, we need an aggressive program, both domestically and internationally to attack this problem, here’s one more signal that we need to do that,” Lance Price, the head of the Antibiotic Resistance Action Center at George Washington University, told STAT News.

Recently, researchers at George Mason University made a discovery that could add to science’s arsenal against antibiotic resistance: the presence of powerful antimicrobial chemical compounds in the blood of Komodo dragons. Continue reading