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Catching snowflakes with glue

Aflevering 83
Wetenschap in een winterwonderland (Foto: Vincent Bourrut)
Wetenschap in een winterwonderland (Foto: Vincent Bourrut)

You don’t always need a big laboratory for exciting experiments. You can capture snowflakes and study them, just by using superglue.

Normally, we go to great lengths to actually try out experiments before writing about them. There are two solid reasons for doing so: it is difficult to know beforehand if the stuff we dream up – or find online – really works and, perhaps more importantly, it’s jolly good fun to mess around in a lab. Especially when it is someone else’s. This time, however, we have to make an exception. That’s because for the following experiment you need microscope slides and fresh snowflakes, and although we have seen more than enough fresh snow in the past few weeks, the problem was that we didn’t have microscope slides. The Catch 22 was that obtaining slides involved a trip to Zernike and that was near to impossible because of the snow. Bottom line: if you intend to pass through the Pearly Gates in a car spinning out of control, don’t let it be a Peugeot.

The reason we still decided to publish this experiment is that it is a very cool trick – no pun intended: catching and conserving snowflakes. All you need, apart from a few slides plus cover slips and fresh snowfall, is a few dollops of superglue (look for cyanoacrylate, the stuff that comes with warnings about gluing your eyelids together).

Start by putting the slides, the cover slips and the glue either somewhere outside or in the freezer to chill them. Then try to catch a snowflake on one of the slides, or simply pick up a fresh snowflake and put it on the slide using tweezers. Place a drop of cold superglue on top and drop a cover slip over it. The warmth of your fingers could melt the snow which would ruin the experiment, so try to push the cover slip in place using tweezers. And try to be somewhat gentle, or you might tear the snowflake. Leave the slide in the freezer for a few weeks to let the glue harden completely.

The experiment works because cyanoacrylate-based glue hardens by forming polymers (long chains of molecules lying head-to-tail) upon contact with water molecules − the very same reason it is so terribly well suited for gluing your eyelids together. The trapped snowflakes last for eternity, or at least thirty years.

To give you an idea: Icelandic chemist Tryggvi Emilsson invented the whole snow-crystal-catchingprocess in the winter of 1979 and the first snowflakes he caught still look as crisp as ever. Go here to see a recent picture of one of his original snowflakes.

One more problem: the best temperature to catch snowflakes is under 5 degrees Celsius below zero, but how do you know when it is minus five when you don’t have an outdoor thermometer? It turns out that it is actually quite simple to write a short script to let your computer send a warning to Twitter at a pre-defined temperature. All you need is a recent version of the Python programming language, a Twitter account and a website with real-time weather data.

Let the program download the website source code, search the text for the temperature and let it send a message when the temperature drops below minus five. Admittedly, it may sound easier to just buy a thermometer, but this is really beginners’ stuff. I know this because I am a beginner – our newborn son is very intolerant of the sound of my Dremel multitool, let alone any other power tools, and coding seemed an interesting and very silent way to satisfy my tinkerlust

Auteur: Ernst Arbouw

Laatst gewijzigd:28 april 2016 16:37