Ever done a Fermi?

Here are few fun questions for you ‘How many piano tuners are there in Chicago?’ or How many people are using cell phones right now in the world? or How many sheep would it take for every person in the world to have a wool sweater? Seems like impossible questions to answer…right?

Is there something we can do or is there some way for us to piece together what is mostly unknown or challenging? 

Join me on this interesting podcast as I share more on the same.

Transcript

Ever done a Fermi?

Hello Everyone and welcome to the podcast of the Ordinary Maverick. This is Ajey, your host, an ordinary Maverick sharing real life thoughts and experiences and Maverick tips. If you haven’t hit the subscribe button yet, please do so, and you’ll not miss another episode.

Enrico Fermi received the Nobel Prize in Physics for his discovery of nuclear reactions caused by slow neutrons. And it was this mechanism that led to the development of atomic bombs and nuclear fission reactors. His work and contribution to science is well recognized for sure. However, he is most known for the famous ‘Fermi question’. It was something Fermi would do to amuse his friends and students by inventing and then also solving whimsical questions like, ‘How many piano tuners are there in Chicago?’…this one is one of the famous ones, actually. But there are several…how much popcorn would fill the room? How many people are using cell phones right now in the world? Or how many airplanes are flying over the US right now? How many hot dogs are bought during the major soccer league season? How many sheep would it take for every person in the world to have a wool sweater? Well….you get the drift…

A Fermi question generally asks for a quick estimate of a quantity that seems difficult or impossible to determine precisely. And the approach is to use common sense and rough estimates of the known to piece together what is mostly unknown!

It’s basically ‘back of the envelope’ calculations that are often done to arrive at some decisions or way forward. And what’s important here is that it helps one to kind of get the answer to a problem using rough estimates before one turns to more sophisticated methods to calculate a precise answer which can take days, months, and even years. What’s also most interesting, is that while putting these estimates together, one actually identifies errors, understands the assumptions and this actually helps problem solve and be better prepared for the intense and long drawn out calculations that one may then need to embark upon to get to the right answer.

One of the most famous Fermi problem is the one about piano tuners. This is how it goes…the question is ‘how many piano tuners are there in Chicago?. Now when one first hears it, you think…Gosh, how ever will I solve this? And maybe one needs a full survey..look at all the data etc etc.

But Fermi approached it with common sense. So here goes… One – look at the population of Chicago – approximately 3 million people. Two – assume that the average family contains four members so number of families in Chicago must be about 750,000. Three – if one in five families owns a piano, then there will be about 150,000 pianos in Chicago. Four – if the average piano tuner services 4 pianos every day of the week for five days, rested on weekends, and took a 2 weeks vacation during the summer…then in one year (52 weeks) he would service 1000 pianos. So 150,000 which is the estimated pianos in Chicago divided by 4 (pianos each day) x 5 (days per week) x 50 (2 weeks vacation so 50 weeks in a year) equals 150.

So there must be about 150 piano tuners in Chicago.

Wow!. Now granted this might not be totally accurate. But one does get a first cut estimate and there could be some degree of error…but the actual figure will be quite close to this estimate. Given that one has used logic and some facts to get to this answer.

This is what Fermi excelled in. In fact his estimate of the strength of the atom bomb was based on the distance traveled by pieces of paper he dropped from his hand during the blast. And his estimate is well within the order of magnitude that is accepted today.

Now what’s even more fascinating is applying Fermi to our life. Try it. Next time you have problems in front of you, use the Fermi principle. Use common sense and logic, as well as whatever information you do have, to make the assumptions and find the solutions.

We’ve done it. Now that I think back, we used the Fermi method, the back of the envelope calculations in buying a house. We didn’t actually have all the money at the time..almost 28 years ago. But doing the estimations, using the assumptions helped us gather courage and jump into committing for buying our first house…an apartment out in the far suburbs in the city of Mumbai…where owning real estate was a dream for many. I think that if we had become very precise to the last dollar, or shall I say the last rupee and done the ‘propah’ calculations…we might not have garnered that courage. Ha Ha…sometimes you just plunge in..right. Deep dive and swim and survive.

We’ve also done the Fermi while moving cities, continents, countries. Calculating the estimated costs of moving to a new country. And while doing so, stumbled upon the problems, writing down the unknowns and then trying to understand these unknowns better. It’s actually helped us get prepared and not caught unawares. Reminds me of how we planned our day out in the Kruger national safari park in South Africa. One needs to calculate distances and time etc as you really don’t want to get locked outside the gates of the camp! In Kruger, one drives around in your own car, taking different roads..but it’s absolutely essential that you reach a camp before a certain time. As once the gates are closed, you are not supposed to be outside. It is you who is in the animal world and not the other way around… well, we’ve gone many times to the Kruger…and always made it back in time. So I guess the estimations were working.

There’s another practical application in real life. Doing these back of the envelope calculations teaches one to continuously create stop points in life and reassess the situation. One realizes that estimates might be wrong, or new information may come up and you need to once again recalibrate. Nothing is finite yes, but starting off with the Fermi approach, thinking big, using estimates, logic and assumptions to find the answer to the most challenging problems including finding what you don’t know and then drilling down to find the answers – all helps in taking the plunge. You know, falling forward…always. 

It’s what they say, Mavericks live life. And one of the first things to do is to START. The Fermi approach does exactly that. Breaks up the seemingly most difficult questions into an answer. And that helps one get started. You can always fine tune as you go along. But if you don’t start and focus on the task at hand, you will never move. 

So fellow Mavericks out there…whatever problem is in front of you today…don’t worry. Just use the Fermi way, and you will find the solution.

Take it from a Maverick who’s always done it and moved forward.

Write your comments, share your feedback, I would love to hear from you. This is Ajey, signing off and wishing you have an amazing day. Keep well.