Gentle warning: although shorter than my average post, it contains a higher than usual geek-like content. You have been warned.
About a month ago, as an early celebration of our 40th wedding anniversary, my wife and I went on a trip to Switzerland – by train. Whilst getting around Switzerland by train, cable car and funicular was a complete joy, it has to be admitted that the haul there and back again was a long one. Even for a supporter of train travel it was long. However, even these journeys had their mitigating factors. The slowly changing scenery moving past our window was one, much as it was when we crossed the Canadian Rockies by train some years back, ending up in Vancouver. On the way out we broke our journey in Strasbourg where, apart from a view of the buildings associated with our soon-to-be-former membership of the EU, I was able to indulge in a little glass-spotting …
The highlight of our vacation, if you’ll forgive the weak pun, was a journey to Europe’s highest railway station, Jungfrauhoch at an altitude of 3454 m (11,371 ft). It’s a stunning location, as many are in Switzerland, and we were fortunate to get only a little snow, low wind speeds, breaks in the cloud and temperatures not too far below 0°C. Just above Jungfrauhoch – accessible via a lift/elevator I’m glad to say – is the Sphinx Observatory (here) at 3571 m. Although not used in the classic ‘star-gazing’ sense, there are several international ecological/environmental research projects based there (here). These include spectroscopic solar observation as a means of probing the Earth’s atmosphere: in others words, looking carefully at what wavelengths light is ‘filtered out’ of the Sun’s rays as a means of identifying with precision the constituents of this high-altitude air. However, as a chronic asthmatic, and having the left-overs from a recent cold the worst symptoms of which had miraculously abated the day prior to our journey, one of my pre-occupations on the day was breathing. In true geeky style, this served to prompt a simple experiment to illustrate the effects of air pressure.
|The Sphinx Observatory; the inset of yours truly not only helps to prove that I was there, but also serves to mask a few unsightly cables.|
I should add in passing that this effect had been noted by my children during a much earlier holiday, in 1998 in fact. This vacation included a stay in Yosemite National Park, within which the altitude varies between about 1200 and 1500 m. Their observation was, in a sense, the obverse of my simplistic experiment: they noted that an unopened bag of crisps (or potato chips in the local language) had inflated like a balloon. What they were seeing, of course, was the effect of higher pressure inside the bag than outside. The bag was sealed in a factory at low altitude, and was about to be consumed at higher altitude: there were more collisions each second between the air molecules and the inside surface of the bag than were occurring at its outer surface.
Ah, the joys of taking physics on vacation. There’s more from Switzerland however.
|This was taken on our very modest compact camera, which was steadied using the window frame in our hotel room.|