Dear reader… gosh it has been a while. I had intended to write more, but alas life has been quite busy recently and the inspiration isn’t quite so easy at the moment. I’m sure you understand. In any case, it is a pleasure to once again have your company, at least for the next few minutes.
The top item on today’s agenda (which you may have guessed if you read the title, you clever thing you) is myths. Given the rich tapestry of topics I usually mention here, it is rather unsurprising that from time time people believe things which are not quite true, and, this afternoon, I shall try to convince you, dear reader, not to believe them.
(You must understand, before we begin, that I’m not trying to be a smart alec here; I genuinely used to believe some of these too)
Myth 1: U-Boats Were Submarines
Not that I would ever suppose to know your thoughts, dear reader, but I suspect many of you are thinking that I must have, in my over-month-long break, finally lost it. One might point out, with just a dash of indignation, that they submerged, didn’t they? Was this not what made them dangerous? Did we not hear that rather amusing story of a U-Boat being sunk by its toilet?
The answer to all of these questions is at least a partial yes. However, most U-Boats spent most of the time on the surface, making them more boats that could submerge (submersibles) than submarines which could surface (a true submarine).
This was because while U-Boats were powered by batteries underwater, they charged these batteries using diesel engines. These diesel engines needed (as diesel engines have an annoying habit of needing) oxygen, which they got from the ambient air, which the sea has an alarming lack of. The exhaust gases also need to go somewhere, and again the air is the ideal place. Hence they had to surface to recharge.
While not exactly quick on the surface at a rather underwhelming 17.7 knots (that’s 20.4 mph), a Type VII U-Boat could only crawl along at an agonising 7.6 knots (just 8.7 mph) under the waves. There are many reasons for this, but one is that the hulls were really designed more for being boats on the surface, and didn’t cut through the water so well under the surface.
Eventually, U-Boats were fitted with snorkels (no really, that is the term) which allowed them to take air and expend exhaust gases without having to surface. Newer types had much larger batteries and were much faster beneath the waves, thanks to better hydrodynamic design, but these types, while among the first real submarines, were a small minority.
Myth 2: The Americans Spent Millions Developing a Space Pen; The Soviets Just Used Pencils
This one is almost true. Both sides of the space race (the big one, not the Hydrogen one I mentioned last time) did initially use pencils.
The pencil is of course a very simple device; when you use one, some graphite is scraped off the end, which gets stuck to the page and shows as the familiar dark grey mark. Not all of this graphite immediately adheres to the page, however. Some is dislodged and becomes dust, which isn’t really a problem on Earth since it falls to the ground harmlessly. In space, however, where the effects of gravity are far lower, this dust gets trapped in ventilation systems, gets stuck in instrument panels, and, since it’s also conductive, can cause electrical problems. This problem gets much worse if you snap the tip of the pencil.
While pencils are sometimes not quite that risky, the space environment can also throw some other problems at the traditional writing instrument. There can be huge changes in pressure and temperature, and there is the risk that any gas dissolved in ink may diffuse out. Thus the Fisher Space Pen was developed to avoid these issues, but that really is a story for another day.
Myth 3: You Can See the Great Wall of China From the Moon
I admit that most of you probably do not believe this, but for those that do, let me explain.
The Earth is actually quite small from the moon, and seeing any man-made object from that distance on the surface of Earth is near-impossible. None of the Apollo astronauts recorded seeing anything on the surface of Earth while on the moon.
In fact, while we’re on the subject, it is really very difficult to see the Great Wall from space full stop. You see, it is made from stone which is not altogether different in colour from the stone in the mountains surrounding it. It also is relatively narrow (in the order of a few metres) making it hard to discern when seen from directly above at a distance of over 60 miles away while travelling at several thousand miles per hour.
Much easier to see from space are cities, if we’re picking man-made objects. On the light side of Earth their much greater area makes them easier to spot and on the dark side the lights from cities make them extremely easy to spot. Indeed, this has given rise to many interesting phenomena, including the fact that you can always spot East from West Berlin because the former east Germany used lightbulbs that give off a slightly different colour of light.
Myth 4: Bumblebees Shouldn’t Be Able to Fly
This one is an odd one because, as is fairly obvious to anyone who has enjoyed a summer in England, Bumblebees do fly. The claim is that according to the “laws of aviation” (whatever that means) the Bumblebee should not be able to fly. I suppose the implication is that nature is way better than us at things, or perhaps someone was just trying to sound clever. We may never know.
This is pure nonsense. As far as anyone can tell, the calculations that “prove” that bees shouldn’t be able to fly were very rudimentary, and were not intended for aircraft of that small a scale. They also ignore the interesting ways in which bees move their wings, and several entomologists (people who study insects) have spent considerable time debunking the myth.
If there’s one good thing we can take out of the myth, it is this; always check your calculations – they may have limitations.
Myth 5: Aircraft Flush Toilet Waste Out
Again, not a difficult one to debunk this (when was the last time a frozen icicle of urine fell where you live?). This is quite obviously not the ideal solution to the problem – instead, toilet waste is retained in tanks on the aircraft and then removed at an airport by specialist vehicles. It isn’t completely unheard of to have a leak of the waste retention tank but it is quite unlikely.
BUT: (some) trains do
While almost all modern trains have retention tanks for toilet waste, this has not always been a requirement. Indeed, there are still many trains in the UK that do just flush toilet waste straight onto the track (this is why you should never flush the toilet in stations) and although they are due for replacement in the next few years this may take longer than planned.
Well, I do hope you enjoyed that detour through some of the many small falsehoods people believe. Now, dear reader, we must part company again (unless of course you choose to read some of my other stuff), and all I can do is wish you a very pleasant day…
PECULIARLY PETE 