Did you know? – Sound


Why do you hear a thunderclap when the sound barrier is broken?

If you throw a ball at 10 Km/hr when stationary, the ball will begin travelling at 10 Km/hr, as it travels through air friction will slow it and it will come to a halt eventually. Let us say you were travelling in a car at 60 Km/hr and threw the same ball, depending on which direction you threw the ball in, it will either travel at 70 Km/hr or 50 Km/hr (for the sake of simplicity, I am not considering vectors).

Unlike the ball, sounds tends to travel at a constant speed depending on the medium that it is travelling in. Also, it is a pressure wave unlike light, which is a transverse wave. The wave leaves the the source and moves at a constant speed through the medium, which may be air, water or even a solid.

This is what a light wave looks like.

This is what a sound wave looks like.

Generally sound travels faster in solids compared to liquids, faster in liquids than in gases. Sound travels at about 1235 Km/hr in air at sea level. It travels a little slower as you go higher since air becomes rarer.

Unlike the case of the ball mentioned above, sound being produced by a jet engine will travel at a constant speed. When the jet begins to approach the speed of sound, every successive pressure wave begins to arrive faster and faster. When a jet reached the speed of sound, the next sound wave arrives before the previous one has been able to move.

Its like someone coming running from behind and slapping you.

This results is what is called interference. In this case constructive interference. The two sound wave collide with one another resulting in the Sonic Boom.

Did you know? – Mesmerised


Anton Franz Mesmer was a German physician in the 18th Century experimenting with magnets to cure maladies. He began by using magnets and soon discovered that he did not even need them. He referred to his approach to curing as Animal Magnetism. Nobody at the time understood what was happening. In the 19th Century one James Braid studied what Mesmer did and proposed to call it hypnosis.

Mesmerised is a word derived from his name to describe a person who is completely captivated.

Did you know? – Oxygenation


I keep learning random stuff, here and there. I never document these things although they might contribute to an interesting read.

I also have a writing problem. It takes me a lot of time to think through things and condense it into a blog AND I am mightily indisciplined.

So for the benefit of other and in order to be able to push out some content regularly, I am going to start writing ‘Did you know?’ It would generally contain something I learnt that I did not already know.

At time, you might already know it, which is fine; other times you might be surprised. If you like this leave a comment, so I know what all the 12 people reading this think about it.

So here goes…


Our blood carries oxygen from our lungs to all of the vital organs in our body. This oxygen is used to burn glucose in the blood stream to produce energy to keep all the organs functioning.

The body does not have any way of detecting the oxygenation levels of blood, but it can detect the CO2 level in the blood.

If you breathe in and hold your breath, you feel this intense need to release your breath because the body wants to push out CO2, not because it seeks Oxygen.

Freedivers use this fact to dive even upto 100 meters without any oxygen. They just keep breathing out enough CO2 and the body is happy!



Subtle changes have the power of making a huge difference. People don’t realise it at the time, but it does.

To Illustrate:

Take a point and draw a line. Now take a 1 degree deflection from the starting point and draw another line. Initially the paths of both lines seem similar but as you go on extending the line the divergence is apparent and huge. And the longer you draw the lines the more the deviation.

Let us assume you are flying a plane from Bangalore to Delhi. If you have a 1 degree deviation in your route, you will find that you land up in Haryana instead of Delhi. The same plane, if it was flying from Delhi to New York would end up in Washington DC with such a small deviation.

Even in absolute terms the difference is subtle but the outcome is wildly different.

Planes do not fly in straight lines, and neither is life a straight line.

Like a deviation can make a huge difference in the long run; so can a nudge or a learning born out a conversation. The effects of these subtle changes can make the difference between success and failure.

Surround yourself with people who can give you the right nudge and push you in the right direction. Gather diversity of thought from a variety of people. They average themselves out and you tend to arrive at good decisions.

A nudge, a push, a casual conversation can change everything.

Rationality and Randomness


When you look up at the sky in the night, you see constellations. Constellations are human inventions, an attempt to ascribe pattern to a random gathering of stars. Why do we do that?

The human brain is tuned to find patterns, it is not tuned to understand the concept of randomness. When you find something which is completely random, you still try to find patterns therein. This is because randomness as a concept is extremely hard to grasp. How can you describe randomness? There is absolutely no model through which you might be able to understand randomness. It is therefore impossible to understand.

Randomness is a part of all of our lives. On a certain day you leave at 8:30 and get to the office at 9:00, while on another you get there at 9:20. Let us say on your first day to work, you left at 8:30 and reached at 10:30 because there happened to be an random accident that happened to block off the road. You would certainly leave early the next day, but it may not be needed.

Which brings us to rationality.

Human are supposed to be rational creatures. We look at all of the information that is available to us and make a rational decision based on the information that is available. At least, in theory that is how we are supposed to be. Having said that almost none of our actions are truly rational.

The stock market is described as a place where all publicly available information about a company is assimilated to give the stock a value, in theory. And, what drives the market – Sentiment!

Rationality is about being able to follow a pattern, model or a rule. A rational decision by design can be deconstructed and the reasoning is apparent. 

Millennia of practice has taught us that the rationality and randomness do not work well together.

One of the experiment often cited is – would you take $50 today or take $100 in 5 months. Often taking the $100 is shown as a sign of patience and rationality; but life is full of random nonsense. What if this person who was offering you the money, got angry with you? Or if they decided not to give after 5 months? Or they died? So, now what would a rational person do?

For all that we may claim to be rational, we are conditioned to think and do things based on past experience rather than pure rationale. 

The randomness of life makes the irrationality of our behaviours just. 

First Times


One of the things that is true about human nature is that our ability to face a situation improves if we have  faced such a situation already.

The first time you change your job, you find the transition a lot harder than thereafter.

If a family has had a case of cancer once, their ability to deal with another member suffering it is much improved.

The first child is always an experiment. Parents don’t worry as much about the second child and the second child also benefits from the best practices learnt from the first.

As an entrepreneur you have to deal with many first times. Keep them coming thick and fast. Face the unknowns as soon as possible. It won’t be the last time you will face it.

Straight ‘A’ students are highly disadvantaged in the real world. A life where you have never faced a calamity, a failure, a disaster leaves you ill-prepared to face it.

Some day you will have to face it, probability has a way of catching up!