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Anthony Zee: Back-of-the-Envelope Calculations
Anthony Zee: Back-of-the-Envelope Calculations
Published: 2012/03/04
Channel: hNeg
Back-of-envelope office space conundrum | Finance & Capital Markets | Khan Academy
Back-of-envelope office space conundrum | Finance & Capital Markets | Khan Academy
Published: 2011/04/18
Channel: Khan Academy
Back of the Envelope Calculations
Back of the Envelope Calculations
Published: 2012/08/24
Channel: EconProfessorKate
Back of the Envelope Calculations
Back of the Envelope Calculations
Published: 2011/01/27
Channel: poworkersforjustice
Back of the Envelope Calculator Tutorial
Back of the Envelope Calculator Tutorial
Published: 2016/03/04
Channel: Seventhwave
Valuate - how to run a multi-family back of the envelope analysis
Valuate - how to run a multi-family back of the envelope analysis
Published: 2016/12/21
Channel: Bruce Kirsch
Back of the envelope  RMS calculations in power electronics
Back of the envelope RMS calculations in power electronics
Published: 2017/03/05
Channel: Sam Ben-Yaakov
Back-of-the-envelope Meaning
Back-of-the-envelope Meaning
Published: 2015/04/22
Channel: SDictionary
Back of the Envelope - Episode 1 - Garbage Calculations
Back of the Envelope - Episode 1 - Garbage Calculations
Published: 2013/02/21
Channel: Leif Masrud
Back of Envelope Proof
Back of Envelope Proof
Published: 2016/04/29
Channel: Carl French
How to do a "Back of the Envelope Cashflow"
How to do a "Back of the Envelope Cashflow"
Published: 2013/12/10
Channel: Banks Consultancy
Beyond the "Back of the Envelope"
Beyond the "Back of the Envelope"
Published: 2014/03/06
Channel: ARPA-E
Financial Aid on the Back of an Envelope
Financial Aid on the Back of an Envelope
Published: 2012/02/26
Channel: Bassoon32
the back of the envelope
the back of the envelope
Published: 2013/12/17
Channel: Hannsoon Smokur
Back Of The Envelope Solution - Design of Computer Programs
Back Of The Envelope Solution - Design of Computer Programs
Published: 2012/06/02
Channel: Udacity
Back of the Envelope
Back of the Envelope
Published: 2013/01/03
Channel: Dick Cross
Back Of The Envelope - Design of Computer Programs
Back Of The Envelope - Design of Computer Programs
Published: 2012/06/02
Channel: Udacity
Back of the Envelope Estimation - ENGN2226 Online Classroom
Back of the Envelope Estimation - ENGN2226 Online Classroom
Published: 2013/10/13
Channel: Chris Browne
파고다원 유용한! 오늘의 영어회화 [back-of-the-envelope calculation]
파고다원 유용한! 오늘의 영어회화 [back-of-the-envelope calculation]
Published: 2016/05/24
Channel: 파고다 PAGODA
MetaMo Training [Thai ver.] (5/6): BoE (Back of the Envelope)
MetaMo Training [Thai ver.] (5/6): BoE (Back of the Envelope)
Published: 2014/07/06
Channel: MetaMoCommunity
Anna Salamon: "How Much it Matters to Know What Matters: A Back of the Envelope Calculation"
Anna Salamon: "How Much it Matters to Know What Matters: A Back of the Envelope Calculation"
Published: 2012/02/21
Channel: singularitysummit
Back of the Envelope Explanation of Real Estate Crowdfunding
Back of the Envelope Explanation of Real Estate Crowdfunding
Published: 2014/11/03
Channel: Can You Find Me Now
Back of the Envelope: Office Space Lease Conundrum: Video Brief
Back of the Envelope: Office Space Lease Conundrum: Video Brief
Published: 2014/11/03
Channel: Oliver Wright
Back of the Envelope - Episode 2 - Addendum
Back of the Envelope - Episode 2 - Addendum
Published: 2013/05/04
Channel: Leif Masrud
Lifetime Gaps
Lifetime Gaps
Published: 2015/09/22
Channel: LatitudesFinancial Strategies
Back of the Envelope Quantum Mechanics With Extensions to Many Body Systems and Integrable PDEs
Back of the Envelope Quantum Mechanics With Extensions to Many Body Systems and Integrable PDEs
Published: 2017/01/27
Channel: Jeremy Frederic
Fermi problem
Fermi problem
Published: 2015/10/25
Channel: Audiopedia
What Is The Fermi Problem?
What Is The Fermi Problem?
Published: 2017/07/22
Channel: tell sparky
Back of the Envelope Quantum Mechanics With Extensions to Many Body Systems and Integrable PDEs
Back of the Envelope Quantum Mechanics With Extensions to Many Body Systems and Integrable PDEs
Published: 2017/01/24
Channel: Hodgetts
How to run an Apartment Development BOTE analysis on Valuate
How to run an Apartment Development BOTE analysis on Valuate
Published: 2017/04/20
Channel: Bruce Kirsch
Back of the Envelope - Episode 3 - Survival Garden
Back of the Envelope - Episode 3 - Survival Garden
Published: 2013/05/07
Channel: Leif Masrud
The financing of extremism/terrorism; Loretta Napoleoni
The financing of extremism/terrorism; Loretta Napoleoni
Published: 2015/09/19
Channel: Universal Tolerance
TENX token post-Ico  price prediction/projection estimate 2018 ?
TENX token post-Ico price prediction/projection estimate 2018 ?
Published: 2017/07/08
Channel: Wealth Of The Future
Estimating the Tangential Velocity of Earth
Estimating the Tangential Velocity of Earth
Published: 2011/10/08
Channel: Timothy Palladino
Stanford Seminar - Runway: A New Tool for Distributed Systems Design
Stanford Seminar - Runway: A New Tool for Distributed Systems Design
Published: 2016/11/03
Channel: stanfordonline
Google-Lenovo Deal: Back of the Envelope Math
Google-Lenovo Deal: Back of the Envelope Math
Published: 2014/01/30
Channel: Bloomberg
Automated Tax Projection Features in VeriPlan
Automated Tax Projection Features in VeriPlan
Published: 2016/06/17
Channel: Larry Russell
I did some back-of-the-envelo
I did some back-of-the-envelo
Published: 2017/06/03
Channel: Nataliia Pinkevich
Can We Retire? A Funded Retirement
Can We Retire? A Funded Retirement
Published: 2015/09/22
Channel: LatitudesFinancial Strategies
Negge Überschlag
Negge Überschlag
Published: 2009/08/16
Channel: Neggenpost
P0016: CKP-CMP Correlation case study: GM 4.3 V6
P0016: CKP-CMP Correlation case study: GM 4.3 V6
Published: 2015/11/14
Channel: Pine Hollow Auto Diagnostics
Dr.ROWLEY explains RATIONAL behind PNM Commitment to RAPID RAIL sysyem!
Dr.ROWLEY explains RATIONAL behind PNM Commitment to RAPID RAIL sysyem!
Published: 2012/10/05
Channel: PNMAbroad
How much coal per kWh?
How much coal per kWh?
Published: 2013/08/25
Channel: Donnie Reinhard
Donut Takes a Tumble
Donut Takes a Tumble
Published: 2013/11/02
Channel: Erin Milligan-Mattes
doppel vw gestreckt
doppel vw gestreckt
Published: 2009/04/11
Channel: Mohre93
Juljas Überschlag
Juljas Überschlag
Published: 2009/09/05
Channel: El0VESN
Grand Theft Auto V - Mach einen Überschlag
Grand Theft Auto V - Mach einen Überschlag
Published: 2015/05/03
Channel: TheRabbit System2
Überschlag Salto übern Tisch
Überschlag Salto übern Tisch
Published: 2009/10/15
Channel: B3n386
Überschlag supi
Überschlag supi
Published: 2016/09/18
Channel: Synex
Dolce  & Gabbana Fall / Winter 2017
Dolce & Gabbana Fall / Winter 2017
Published: 2017/02/27
Channel: Next Management
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WIKIPEDIA ARTICLE

From Wikipedia, the free encyclopedia
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A back-of-the-envelope calculation is a rough calculation, typically jotted down on any available scrap of paper such as the actual back of an envelope. It is more than a guess but less than an accurate calculation or mathematical proof. The defining characteristic of back-of-the-envelope calculations is the use of simplified assumptions. A similar phrase is "back of a napkin", which is also used in the business world to describe sketching out a quick, rough idea of a business or product.[1] In British English, a similar idiom is "back of a fag packet".

History[edit]

In the natural sciences, back-of-the-envelope calculation is often associated with physicist Enrico Fermi,[2] who was well known for emphasizing ways that complex scientific equations could be approximated within an order of magnitude using simple calculations. He went on to develop a series of sample calculations, which are called "Fermi Questions" or "Back-of-the-Envelope Calculations" and used to solve Fermi problems.[3][4]

Fermi was known for getting quick and accurate answers to problems that would stump other people. The most famous instance came during the first atomic bomb test in New Mexico on 16 July 1945. As the blast wave reached him, Fermi dropped bits of paper. By measuring the distance they were blown, he could compare to a previously computed table and thus estimate the bomb energy yield. He estimated 10 kilotons of TNT; the measured result was 18.6.[5]

Perhaps the most influential example of such a calculation was carried out over a period of a few hours by Arnold Wilkins after being asked to consider a problem by Robert Watson Watt. Watt had learned that the Germans claimed to have invented a radio-based death ray, but Wilkins' one-page calculations demonstrated that such a thing was almost certainly impossible. When Watt asked what role radio might play, Wilkins replied that it might be useful for detection at long range, a suggestion that led to the rapid development of radar and the Chain Home system.[6]

Another example is Victor Weisskopf's pamphlet Modern Physics from an Elementary Point of View.[7] In these notes Weisskopf used back-of-the-envelope calculations to calculate the size of a hydrogen atom, a star, and a mountain, all using elementary physics.

Examples[edit]

Nobel laureate Charles Townes describes in a video interview for the University of California, Berkeley on the 50th anniversary of the laser, how he pulled an envelope from his pocket while sitting in a park and wrote down calculations during his initial insight into lasers.[8]

An important Internet protocol, the Border Gateway Protocol, was sketched out in 1989 by engineers on the back of "three ketchup-stained napkins," and is still known as the three-napkin protocol.[9]

The 2001 policy of New Labour to abolish the office of Lord Chancellor has been seen as a rushed "back-of-an-envelope" plan.[10]

See also[edit]

Notes and references[edit]

External links[edit]

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