Slinky, Slinky, Everone Loves a Slinky…

2011-09-20 19:20:12.000 – Ryan Knapp,  Weather Observer/Meteorologist

Temperatures oscillating like a slinky.

One thing that I remember all my college science classes (chemistry, biology, physics, and of course meteorology) having in common was a slinky. This isn’t some fancy science term; this is the metal helical spring toy that you probably remember having or seeing at some point in your life (but just in case, you can check out this Wikipedia page for more information). The reason why it was commonly used was it was good visual example of one or more topics in each science. The two common methods of demonstration were either stretching the slinky out between two points or walking the slinky down the stairs.

By stretching it out between two points or people, the professors could express several wave patterns as well as how energy transfers. In Geology, this method demonstrated earthquake wave patterns and propagation (Primary or “P” waves, Secondary or “S” waves, Love waves, or Rayleigh waves). In chemistry it showed how some particles move or interact with each other. In biology, it demonstrated how some species move (kangaroos, side-winders, etc) or how things move and interact at smaller levels (amoebas, blood cells, etc). In physics and meteorology, it showed (among many things) how light waves move, sound waves move, water waves move, and atmospheric waves move. And by setting them up at the top of “stairs” (usually stacks of books) and then walking them down the stairs, the various sciences could demonstrate motion, inertia, gravity, potential energy, kinetic energy, longitudinal waves, speed, tension, energy transfers, Newton’s Law’s, and a few other laws which all the sciences have in common.

In meteorology, like I mentioned above, the slinky demonstrated light waves, sound waves, water waves, and atmospheric waves but since it created a sine wave shape when moved up and down, it was also used in our climatology course. When weather elements (precipitation, snowfall, temperature, etc) are graphed out over extended periods of time (2+ years usually), an oscillating slinky (or sine wave) can usually be seen. Precipitation (at least for California stations where I went to school) shows the wettest month occurring in the winter and the driest occurring in the summer. While this may not be true of all stations, it does ring true for snowfall for most stations with the most snow falling in winter months and the least occurring in the summer. With temperatures, the top of the wave is during the summers typically representing the warmest temperatures with the bottom of the wave occurring during the winter months. This certainly rings true here. As an example, I graphed the highs (in red) and lows (in blue) from June 2008 to yesterday (the black line is the normals). In the graph, you can see an oscillating slinky (or sine wave) shape coming about. While you could pull a few things from the graph, the main point I wanted to express in the graph (and this comment) is we are past the peak, or warmest days, of the year. Days are getting shorter, operating hours are getting shorter and very weather dependent, and temperatures are getting colder. Since it’s been said that the summit only has two seasons, summer and winter, it’s time to start looking closer at forecasts and thinking, packing, and dressing like it is winter again because it’s all (on average) downhill from here.

Ryan Knapp,  Weather Observer/Meteorologist