The Birthday Paradox

By Anupum Pant

Imagine you meet a random person in the street and ask him/her when is their birthday, there’s a huge chance that the person’s birthday will not be the same as your birthday. In fact, the probability of both your birthdays being on the same day is around 0.27%. Fat chance. At the back of our heads, this is something that is very clear to all of us.

Again, if you repeat this by asking about 22 people the same question, the chance of you finding someone having the same birthday as yours is still around 5%. Too less. This is too is a very intuitive piece of information.

But consider this. If I put all of the 22 guys and you in a room, there’s a big chance that 2 people in that room will have the same birthday – a 50% chance. Moreover, if there are 70 people in the room, this chance increases to about 99.99%. This is called the birthday problem or the birthday paradox.

So, what changed when 20 people went into the room? It was just the fact that in the room, we are picking 2 people from a group of 23 people. That is equivalent to this – everyone is asking everyone their birth dates. Everyone doing it simultaneously makes the probability much higher. The probability of two people sharing a birth date among a group of 23 people is far higher than you alone going around and asking all the 22 people, and finding someone having the same birthday as your’s.

Suppose there are 200 people in the room. The probability of 2 people sharing their birthday is massive (and yet not definite). There is in fact a 99.9999999999999999999999999998% chance!


Finally, if you had 367 people in a room, at least a pair among these 367 people in the room would definitely have the same birth date. The 99.99% chance shoots up to a definite (100%) probability if there are 367 people in the same room. Think about it for a minute.

Problem Solving Plants

By Anupum Pant

Neurobiological research on plants, sounds absurd, right? Not at all. Stefano Mancuso from University of Florence, Italy has devoted years of his life studying plants and he firmly believes that plants can communicate.

He often uses bean plants to demonstrate their mystical ability to communicate and their amazing ability to sense the environment. He has grown bean plants in a number of conditions (lighting, temperature, humidity, magnetic field etc.), while recording their growth through a time-lapse camera.

In his time-lapse videos it’s fascinating to see bean plants shooting out and making movements, as a blind man would do with his hand to sense the environment. Every single time, irrespective of its distance, bean plants are able to find the support stick to wind on…

This remarkable ability of bean plants, lacking eyes or any other known sensing techniques, has stunned scientists. Since it is sped up, the video of this shoot moving up the support stick looks a lot like some reptile’s movement.

Here, watch the time-lapse, you’ll see how amazing this little marvel of nature is…

Like a bean plant, there is another plant (if you could call it that), whose movements have interested scientists. Exactly like a bean plant does, this plant comes out too, searches and always is able to find another plant to grow on. At the same time, it is quite different from the bean plant.

Cuscuta Pentagona, as scientists call it, is a true parasite. That means, it has no roots, nor can it make food on it’s own – no photosynthesis. So, for food, it relies on neighbouring plants. And every single time, like bean plant, after coming out from the ground, cuscuta parasite is able to sense the healthiest plant. It then sinks in its suckers to suck out food from the host plant. Now watch the serial killer in action, in the voice of Morgan Freeman.

Why Do Bad Eggs Float?

By Anupum Pant

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Instead of cracking up an egg which has been stored for a long time, to end up disgusted by the ‘rotten egg smell’, or the smell of a gas called Hydrogen Sulfide, a simple and a fairly well known way to check if an egg has gone bad, is to drop it in a glass of water and see if it floats. I found out about this first, from an article written at Frugal Living, and spent some time to confirm its claims – Bad eggs float.
If you take my word for it (you should!), it really does work. The article describes this three-point test to find out if an egg is good to eat.

  1. If the egg sinks and lies on its side, it is a fresh one. It is good enough to be eaten.
  2. If it sinks and stands up on a point, or is at an angle, it is good enough. You can still use it up for making hard-cooked eggs or bake it.
  3. But, if an egg floats, it needs to be discarded.

Why does this happen?

To understand, you’ll have to think of a chick – a young chicken.

Poor Chicks: Before chickens come out of the egg, they develop lungs and need oxygen to breath. Sitting inside a sealed egg, with no cords attached, for the chick to survive, oxygen has to come in from somewhere. For that, let us look inside.

Egg Science: The outer shell of an egg has two membranes under it. When an egg is laid, it is warm and starts cooling which contracts the inner part of the egg more than the shell and pulls the two membranes apart. As a result, air gets trapped in between the membranes (not enough air initially for it to float).

How does the air come in? The shell of an egg isn’t as simple as it looks. It has about 7000 tiny pores in that shell which let the air pass in and let the carbon dioxide pass out of it. This is how the chick breathes. And the reason, eggs boiled in colored water during Easter, get colored from the inside.

So, as there are pores present in the shell, bacteria enter the egg and start decaying the biological matter inside. This produces a smelly gas (and other gases too), Hydrogen Sulfide (also present in smelly farts). The gases from this decomposition, and the air from outside, keep increasing in volume as time passes.

Corollary: This is exactly what explains these floating bad eggs – Greater the amount of gas inside, older is the egg and the better it floats in water.

Side note: Egg shells and the two membranes inside have the ability to stop the invasion of micro-organisms and bacteria, but over time bacteria manage to enter.