A Crazy Way To Explore Respiratory Aerodynamics

We need to breathe in order to live. So respiration is a vital part in sustaining life. The tissues take up Oxygen for burning of ‘fuels’ such as carbohydrates and fatty acids, for the production of energy; and produce CO2 or Carbon di Oxide as a result. This ‘internal respiration’ is actually ‘cellular respiration’.
CO2 then goes to the lungs and exhaled out. Fresh Oxygen from air gets in. This is ‘external respiration’ and the lungs acted as an organ of gas exchange.

We can’t really see any air coming out of our nose or mouth; this is because the optical density of exhaled or inhaled air is somewhat similar to the surrounding air. Wouldn’t it be nice if we could actually see them? The way ‘air’ came out, the 'aerodynamics' part; and the way it smoothly mingled with the surrounding air, the 'diffusion' part?

Well, tobacco smoke could be suitable for this rather crude experiment. There is NO DOUBT that tobacco in any of its forms is injurious to health, and I am in no way advocating its use for any purpose, not even here. But there are guys who do smoke. If you look at the expired ‘air’, you can ‘see’ how the thick dense smoke that exits from the mouth gets thinner, as it expands, as the ‘air’ goes further away from the smoker. In a sense, we are 'watching' how exhaled air would actually come out from us, its trajectories and its aerodynamics!

Over a certain period of time, we can see that the density of the smoke diminishes and we can no longer see that wisp of smoke separate from the ambient air. This is due to diffusion of smoke particles down the concentration gradient; surrounding air may be assumed to have zero concentration of smoke, for all practical purposes.

However, one thing that is still ‘smoky’ to me is how the smoke rings, that 'artistic smokers' can produce, behave.
As shown in the picture, one such smoker is seen making circular rings of smoke. Both the outside and the inside of the rings are 'not visible' and we may assume them to be consisting of air rather than smoke. Now as the ring move further away, both the internal and external diameter of the exhaled smoke-ring increase. Provided that the procedure is carried out in a room where there is hardly any air flowing, and stray electrostatic charges are absent; extraneous artifacts can then be minimized and faithful aerodynamics may be expected. If one plots the trajectory of the smoke-ring over time, he will get the result as shown in the picture.

If we now joined the outer peripheries of consequetive rings, we would get a cone. Quite expectedly, the narrower end of this ‘outer cone’ will correspond to the inner margin of the artistic-smoker’s lips. Problem occurs when we construct the inner cone, by joining the internal circumferential points of those rings. Where does the narrower end correspond to now? Honestly, I’m not sure. Clearly, it is somewhere within the mouth (oral cavity). I have asked a few such ‘annular performers’ about how they achieved this feat. Gathering and analyzing data from these hallowed ‘Lords of the rings’ have suggested that the actual ‘point of origin' corresponded to somewhere in the middle of the oral cavity. They used the bases of their tongues to maneuver the smoke by apposing it to the hard palate, and then gently pushed the smoke out. The pharynx and the larynx were automatically shut off in the process.

What is your opinion? Quite some feat anyway!

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Magnus Effect: Swerving the Ball

Tomorrow the festival of colors, Holi will be celebrated all over India with zeal and enthusiasm. Another festive occasion is about to begin in the Caribbean Islands, exactly 11 days hence. The cricket world cup will begin. Cricket is played by few countries across the world, most of them commonwealth nations. Though I was never a sports enthusiast (and I still not am), I do enjoy seeing the game sometimes. This time Australia is my favorite, but team India is not far behind.

I will miss Shoaib Akhtar, the Pakistani speedstar, also known as the Rawalpindi express; Brett Lee, the pacer from 'down under', i.e. Australia; Oram, the Kiwi (New Zealand) allrounder and many a great faces. Oram, of NZ, suffered an injury to his finger, for which he has been declared unfit for the game. But such is his passion for the game, that he prefers amputation of his finger, if that could mean his inclusion in the team. He prefers to play than to sit idle, even if it comes at the cost of his finger!

Some pacers can swing the ball like sultans (Sultans of swing). The swings (horizontal arcs, as you can see in the picture) observed in the trajectory of the cricket ball (also seen in table tennis, tennis, footballs etc.) is a really interesting phenomenon to me. It is not like lopping, which can be explained in terms of gravity, but this horizontal swing seems logic defying. How can an object change its trajectory once it has been ejected? No external force, other than friction and gravity seems to be acting, then why this horizontal deviation? This apparently seems to contradict Newton's first law. This has been attributed to the aerodynamic interaction that occur with the ball. This interaction is known as Magnus effect.

I hope that this explanation of science on this game doesn't put you off. If so, I beg your pardon for making your Rum tasting bitter and the calypso so cacophonic. As of me, I would probably have to bear with the possible lackluster performance of one time batting maestro, Sachin Tendulkar in this tournament.