True Science for a Real World

Saturday, June 28, 2014

Infinite Chocolate

Not so long ago, a friend of mine posted a video in which someone would, apparently, continuously over and over again chopped a square of chocolate off a larger rectangular bar. Some ventured even far enough to call it a method for getting an unlimited supply of the precious cocoa-based delicacy.

Alex attempting to repeat the feat he just saw on the Internetz

Nevertheless, to the misfortune of those many who actually tried, the experiment came to be of little or no success in real life. What?! But why?! If it's so damn clear in the video!!


Lavoisier had very accurately stated in the mid 1700s what was his wife's most dreadful nightmare: mass always remains the same. That is, slicing the chocolate and re-arranging its shape does not create more chocolate.

After years of hard work and dedication, Antoine reveals a dreadful conclusion to Marie-Anne
On the same note, my friend qualified the video as magic and asked a former Maths Teacher to provide further explanation on the poorly understood phenomena. The wise Professor, instead of swiftly responding the question, requested his past students to input into the conversation... After some thinking and a lot of chocolate eating, I reached a conclusion and decided to share my view on it.

First, we get a chocolate bar like the one shown in the video (or at least one fairly similar to it). For our purposes, a hypothetical bar of dimensions 4 x 6 will be enough. Let's analyze the area of such bar by splitting as proposed by the video.

Just for fun, let's make sure that the sum of the areas is in fact the total area:

The Math works!! And yeah... I sometimes do this for fun

The next step is then to test the main message of the video; that by moving stuff around we'll get more chocolate. Piece B is moved to where A and C were, and it is supposed that the total chocolate remains the same after taking away C. Therefore, the author claims that the first column of B has the same area as A and C. We are going to test this hypothesis and find whether it's true or not.... SPOILER ALERT: it's not.

Let B' be the first column of B, then B' = A + C or is it??

How do we test this? As we did in the past, checking for the surface of the individual parts. By doing this, we can easily tell that the hypothesis was wrong (duh!)

The null hypothesis is rejected and we keep the alternative statement: B' does not equal A + C

However, Alex is still not quite convinced. After all he really wanted some more chocolate, and who's to blame him? As a matter of fact, if you perform the steps shown in the video you will get a similar piece of chocolate as the starting one, but a little bit smaller. How smaller you ask? Well, one square out divided by four squares on the base, the total height of the bar went down by 1/4, thus making a brand new bar of dimensions 4 x 5.75 which, to the naked eye might look pretty much the same.

Arrrggghhhh... So close!

And even if you were stubborn enough to try again and go for a second iteration on the process shown in the video, you well then find the truth right away. There will be a difference in the height of the chocolate bar. This is because the 3rd row took all the 0.25 height reduction and those squares are not squares any more!

And what's even more evident now is that the 3rd row is quite compact... having taken a second hit on its height.

After yet another bar of chocolate, all these experiments led just to more questions: if you fuse the chocolate after the first iteration, could you repeat the whole process again? The answer is yes, but still no infinite chocolate. You'll just be trimming the bar and getting a smaller chocolate bar on every iteration:

How smaller will it become after each iteration? How many iterations can you do? What's the area after n iterations?

The area of the chocolate after n iterations is given by

For example, when you start the area of the original chocolate is 24

After removing the first square, then it would be

The height of the chocolate after iteration n is 

The area of each square after iteration n, which by the way is the same as its height since its base is always one unit (hence a small rectangle; not a square), is

The former number is physically possible as long as it is larger than a number x such that x is the minimum or tiniest particle of chocolate, which occurs if the number of iteration n is such that

Let's say that the chocolate is mainly glucose, then x is the diameter of a molecule of glucose
x = 1.5nm

First let us agree on the units of the chocolate measures... say cm; a chocolate bar of 24cm^2 sounds decent. So: 

We can iterate around 370 times. At this point the area would be of close to 0.00000347817 cm^2 and we would definitely notice that it is not the same as the original (naturally), plus each and every piece sliced away constitute the original bar, while each and every piece is different from each other.

Regardless of how we look at it, Lavoisier was and still is right.

Special thanks: 
To Gabs, for teaching me how to curse in French.
To Horace, for supplying heavy math stuff.
To Alex, for raising the question.
To Jose Manuel, for teaching me maths during High School.

Saturday, January 11, 2014

The Invisible Slap

A friend of mine was recently disappointed due to the ridiculously low offer made by a potential boss to start a new job. As most people who feel disappointed towards the salary, she felt she was overqualified, having tons of experience, the right background from prestigious universities for both undergrad and Master's degrees, all the confidence and the adhoc personality.

Anna shows off her more than impressive background

It was just obvious that she passed the hiring bar by a wide margin, but ultimately was slapped by Adam Smith's invisible hand right in the face when she was extended an offer.

Adam Smith's invisible hand slaps Anna in the face

Supply and demand is quite often misunderstood principle of Economics. It has extensive application on real life!!

It works like this: an employer has a vacant position and offers a given amount of pay as salary. The market has at the same time potential employees or people who seek employment. These candidates reach out to the employer and if they meet the expectations they are extended an offer, in which case they can accept it or not.

IF the candidate accepts an offer, the employer is happy that he filled the outstanding position and understands that if another similar position opens up in the future it is ok to make a similar offer or perhaps even decrease it a little bit. Who knows? Maybe he offered too much and that's the reason why the candidate took the position in the first place.

IF the candidate rejects the offer, the employer scratches his head in confusion and determines that maybe the candidate wasn't happy about the offer, hence he decides to increase the benefits of coming to work in this position. Whether it is by increasing the base salary, bonus rewards, relocation aids, stock options, more vacation time, dental plan, corporate car or whatever, the punchline is that the employer will try to make the offer more appealing to future candidates.

Naturally, there are many companies with many outstanding job offers and many people seeking job opportunities everywhere, thus making this cycle extremely dynamic and so it's difficult to determine who has the upper hand on the mechanics of this game:

If there are many people out there who can perform the job and are willing to take the pay level, then it's tough luck for you; the employer will just hire the next guy who's willing to take the offer.

A candidate with less experience and qualifications is likely to accept a less rewarding job

Highly demanding candidates will be sent to the shark pit regardless of their qualifications in excess of the hiring bar

In contrast, if the skill set requested to perform on the job is quite particular such that you stand out as one of the few who can do it, then that's the time to get cocky and ask for a big fat signing bonus, third-world-politician-like salary* and a bigger office.

When the qualified candidates are few and far in between, the employer will expand the offer to unimaginable extents

To sum up, while it is true that you could alter the offer in your benefit by convincing all the other applicants to reject it, it's nearly impossible to get that ninja guy** to reject an offer, especially if full of debt. It's a stalemate. The next time you're made a job offer do your due diligence in advance. Know what's the market average for similar positions in similar companies and use this knowledge to make a better assessment of your choices.

*This means very, very high. Usually associated to an insanely high pay per actual work ratio
**No Income No Job or Assets 

Some resources and further reading:

  1. Shake the Invisible Hand
  2. Learn the ABC of Economics
  3. Dive deep!


  • The characters appearing in this work are fictional. Any resemblance to real persons, living or death, is purely coincidental... not!
  • Obviously, I don't own the shark image.
  • I don´t know how to draw sharks (or anything else for that matter).