1
Back of the Envelope Calculations
Back of the Envelope Calculations
DATE: 2012/08/23::
2
Back of the Envelope - Episode 1 - Garbage Calculations
Back of the Envelope - Episode 1 - Garbage Calculations
DATE: 2013/02/21::
3
Anthony Zee: Back-of-the-Envelope Calculations
Anthony Zee: Back-of-the-Envelope Calculations
DATE: 2012/03/04::
4
Back of the Envelope - Episode 3 - Survival Garden
Back of the Envelope - Episode 3 - Survival Garden
DATE: 2013/05/07::
5
Back of Envelope Office Space Conundrum
Back of Envelope Office Space Conundrum
DATE: 2011/04/18::
6
How to say back-of-the-envelope calculation in German | German Words
How to say back-of-the-envelope calculation in German | German Words
DATE: 2014/12/23::
7
Estimating the Tangential Velocity of Earth
Estimating the Tangential Velocity of Earth
DATE: 2011/10/08::
8
Six months of holidays a year. Only in Akhilesh Yadav
Six months of holidays a year. Only in Akhilesh Yadav's Uttar Pradesh
DATE: 2015/04/21::
9
The Dangers of Trampolines - My True Confession: SingingDrJosh - The Singing Pediatrician
The Dangers of Trampolines - My True Confession: SingingDrJosh - The Singing Pediatrician
DATE: 2012/12/02::
10
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"
DATE: 2012/02/21::
11
Mirada targeting 4mln cable customers in Mexico
Mirada targeting 4mln cable customers in Mexico
DATE: 2015/02/17::
12
MetaMo Training [Thai ver.] (5/6): BoE (Back of the Envelope)
MetaMo Training [Thai ver.] (5/6): BoE (Back of the Envelope)
DATE: 2014/07/06::
13
How much coal per kWh?
How much coal per kWh?
DATE: 2013/08/24::
14
Frontiers of Science
Frontiers of Science
DATE: 2007/04/25::
15
Back of the Envelope - Episode 2 - Addendum
Back of the Envelope - Episode 2 - Addendum
DATE: 2013/05/04::
16
Stock Selection Process For Momentum Breakout Stocks Part 3
Stock Selection Process For Momentum Breakout Stocks Part 3
DATE: 2013/09/10::
17
Gian Fulgoni Chairman & Co-founder, comScore (Festival of Media 2009) Part 1
Gian Fulgoni Chairman & Co-founder, comScore (Festival of Media 2009) Part 1
DATE: 2010/08/10::
18
NASA Spacecraft Dawn @ Dwarf Planet Ceres - What are those Bright Spots? - Possibility Of Life!
NASA Spacecraft Dawn @ Dwarf Planet Ceres - What are those Bright Spots? - Possibility Of Life!
DATE: 2015/04/02::
19
Gian Fulgoni Chairman & Co-founder, comScore (Festival of Media 2009) Part 2
Gian Fulgoni Chairman & Co-founder, comScore (Festival of Media 2009) Part 2
DATE: 2010/08/10::
20
HydroPad Demo
HydroPad Demo
DATE: 2012/03/23::
21
The best (scripted) wedding toast ever!
The best (scripted) wedding toast ever!
DATE: 2012/10/07::
22
Not Your Typical Commute To Work: Flight to Canada Glacier, Antarctica
Not Your Typical Commute To Work: Flight to Canada Glacier, Antarctica
DATE: 2015/03/19::
23
Back-of-the-envelope Meaning
Back-of-the-envelope Meaning
DATE: 2015/04/22::
24
My Voyage from Migrant Farm Worker to Brain Surgeon
My Voyage from Migrant Farm Worker to Brain Surgeon
DATE: 2012/01/24::
25
HUMANITARIAN CRISIS ON THE SOUTH BORDER, KIDS CROSSING UP FROM GUATEMALA
HUMANITARIAN CRISIS ON THE SOUTH BORDER, KIDS CROSSING UP FROM GUATEMALA
DATE: 2014/06/12::
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Dr. Frank Wang calculates power generated by Hoover Dam
Dr. Frank Wang calculates power generated by Hoover Dam
DATE: 2011/07/19::
27
What Cost Did Orioles Pay for Game Played at Vacant Stadium?
What Cost Did Orioles Pay for Game Played at Vacant Stadium?
DATE: 2015/05/04::
28
Heath Ceramics - Beautiful MUSA Tableware, Responsibly (extended version)
Heath Ceramics - Beautiful MUSA Tableware, Responsibly (extended version)
DATE: 2011/10/11::
29
Karl Johanson
Karl Johanson's Paper Starship
DATE: 2008/11/30::
30
buyMUSA: We Can Do This (:30)
buyMUSA: We Can Do This (:30)
DATE: 2011/09/21::
31
buyMUSA: We Can Do This (:60)
buyMUSA: We Can Do This (:60)
DATE: 2011/09/04::
32
Estimating Ammonia Emissions from Livestock Using Low-Cost, Time-Averaged Concentration Measurements
Estimating Ammonia Emissions from Livestock Using Low-Cost, Time-Averaged Concentration Measurements
DATE: 2013/05/29::
33
Clinton Supporters Ready To Take Fight To Convention
Clinton Supporters Ready To Take Fight To Convention
DATE: 2008/04/21::
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Dr.ROWLEY explains RATIONAL behind PNM Commitment to RAPID RAIL sysyem!
Dr.ROWLEY explains RATIONAL behind PNM Commitment to RAPID RAIL sysyem!
DATE: 2012/10/05::
35
Which five A1 companies pass Roger Montgomery
Which five A1 companies pass Roger Montgomery's cash flow test?
DATE: 2011/06/16::
36
Straight Up-Derivatives, Bailouts and YOU Part 1
Straight Up-Derivatives, Bailouts and YOU Part 1
DATE: 2009/01/29::
37
Heath Ceramics - Beautiful MUSA Tableware, Responsibly
Heath Ceramics - Beautiful MUSA Tableware, Responsibly
DATE: 2011/10/11::
38
How does Roger Montgomery quickly calculate cash flow?
How does Roger Montgomery quickly calculate cash flow?
DATE: 2011/06/03::
39
John Heins & Whitney Tilson: "The Art of Value Investing" | Talks at Google
John Heins & Whitney Tilson: "The Art of Value Investing" | Talks at Google
DATE: 2014/12/10::
40
AGI 2011: The Future of AGI Workshop Part 1 - Ethics of Advanced AGI
AGI 2011: The Future of AGI Workshop Part 1 - Ethics of Advanced AGI
DATE: 2011/08/31::
41
Basics of M&E in PPD, Section 5: Cost Benefits Analysis
Basics of M&E in PPD, Section 5: Cost Benefits Analysis
DATE: 2014/07/23::
42
cc TECH IN 2014 - Luis Von Ahn
cc TECH IN 2014 - Luis Von Ahn
DATE: 2014/12/02::
43
An example of how to calculate the value of my small busine
An example of how to calculate the value of my small busine
DATE: 2009/10/09::
44
Graham Hancock - The War on Consciousness BANNED TED TALK
Graham Hancock - The War on Consciousness BANNED TED TALK
DATE: 2013/03/15::
45
How to Select Compression Springs
How to Select Compression Springs
DATE: 2012/12/20::
46
Image to 3D - NTB
Image to 3D - NTB
DATE: 2013/08/15::
47
Affordable Aluminium Foil Insulation Melbourne - In Stock Now!
Affordable Aluminium Foil Insulation Melbourne - In Stock Now!
DATE: 2010/12/12::
48
Video #3: Third Party Certifications | Portland Home Builder, Legend Homes
Video #3: Third Party Certifications | Portland Home Builder, Legend Homes
DATE: 2013/01/14::
49
Five Cost Saving Tips for Dimensional Weight Shipping with FedEx and UPS | Part 3
Five Cost Saving Tips for Dimensional Weight Shipping with FedEx and UPS | Part 3
DATE: 2014/10/10::
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Back-Of-The Envelope Aerodynamics
Back-Of-The Envelope Aerodynamics
DATE: 2012/03/09::
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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 hard 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]

Another example is Victor Weisskopf's pamphlet Modern Physics from an Elementary Point of View.[6] 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.[7]

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.[8]

See also[edit]

Notes and references[edit]

External links[edit]

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