Comments, contributions, thoughts, musings, etc are welcome and
What are these pages?
Here are resources on
( back of the envelope
/ rough and ready
/ order of magnitude
/ thinking on your feet
Standing on the back of the envelope, one can see much of the
universe. I have found it a vantage point of great power and beauty, but
unfortunately one much neglected. It is my hope, in collecting
these resources, to increase its accessibility, and to draw greater
attention to it.
- Mitchell N Charity
I welcome and appreciate your questions, your thoughts, and your contributions.
It is rather remarkable how much we can understand our world.
But the opportunity is often obscured.
Either by sacrificing numeracy for simplicity, and finding both lost.
Or by failing to sacrifice trivia for understanding.
But there is a middle path.
One of models and math both simple and powerful.
Of thoughtfully chosen, `good enough' precision.
Of knowledge, live and insightful, which reveals rather than obscures.
A path, and a view, from the back of the envelope.
Encourage the use of the back of the envelope,
by collecting resources and broadcast.
In particular, support the memes
These pages are currently strongly biased towards physics. I believe
BotE's applicability to be much more general. I have a couple of
history pages in mind to illustrate.
- BotE is desirable.
- BotE is a good way to develop deep knowledge.
- BotE is accessible to young children.
- To support BotE, introductory material should have certain properties.
Having some free time, I wanted to improve my understanding of the
world. Brushing up my understanding of order of magnitude calculation
seemed a good place to start. But I didn't find a good description
online. But no problem, as teaching is a great way to learn something
deeply, I set out to create one. As I pushed into the paper
literature, and broadened my scope to back of the envelope work in
general, I became increasingly bemused. It seemed that the back of
the envelope was even more delightful, powerful, accessible to
children, encouraging of deep understanding; even more of an all
around neat thing than I had realized. There were scattered
columns in various fields saying, this is good, we should more of it.
But it still doesn't seem common. I have found it difficult to find
introductions and resources. Perhaps another example of neat stuff
currently being transmitted mainly by osmosis / apprenticeship.
It being difficult for people to use what is difficult to find,
this then is a collection of introductions and resources.
As seems to so often happen, you set out to do something simple and
straight-forward, but can't seem to find the tools you need, and thus
end up in the tool creation business.
Who am I?
I've spent the last few years working on the architecture of
global-scale information systems, at MIT's Laboratory for Computer
Science, my salary coming from your tax dollars via DARPA. I have
moved on to consulting, but needed a vacation, and A View from the Back of the
Envelope has been part of it.
- Mitchell N Charity <email@example.com>
These pages cover thought, and some bare-hands observation (but
nothing which requires having built tools), but little subsequent
action. One can imagine a follow-on, A View from the Engineer's
Workbench, with tool building and environment observation and
manipulation, targeted at kids and everyone. Stuff like E&M
coke bottle viewers, child-built "temporary" furniture,
engineering with stuff around the house, expanding your
observation/manipulation envelope, force transmission, etc etc etc).
But that is yet another big hunk to bite off, so first I'll see how
this one goes down.
Thanks go to the various people who have written columns and books
(and web pages) with a BotE flavor. To an MIT professor, whose name
escapes me, who taught a brief IAP seminar some years ago on Wise
Approximate GuesseS (WAGS).
To the librarians of the Minuteman Library Network, and Boston
Library Consortium. One still needs to spend money to get a decent
literature search capability, but it has been a great resource.
Specific thanks for suggestions and encouragement to: Suzanne
Barricelli, Alan Bawden, Carolyn Breen, David Luongo, Philip and
These pages are hosted by Vendian Systems.
It's been a while since this page was reviewed...
1997.Aug.13 Added some names to `thanks'.
1997.Jul.30 Upgraded format without touching content.
1997.Jul.12 Yanked in intro paragraphs from top page.
distant past Created.