caustics
Caustic (optics)
Caustics made by the surface of water.
In optics, a caustic is the envelope of light rays reflected or refracted by a curved surface or object, or the projection of that envelope of rays on another surface. The caustic is a curve or surface to which each of the light rays is tangent, defining a boundary of an envelope of rays as a curve of concentrated light.
Hiding Images in Plain Sight
An Article by Matt FerraroI recently made a physical object that defies all intuition. It's a square of acrylic, smooth on both sides, totally transparent. A tiny window.
But it has the magic property that if you shine a flashlight on it, it forms an image.
Caustic Engineering
An Article by Geoff ManaughA piece of milled plexiglass acting as a projecting lens; via the Computer Graphics and Geometry Lab at the École Polytechnique Fédérale de Lausanne
New milling techniques applied to glass and plexiglass panels could be used to “create windows that are also cryptic projectors, summoning ghostly images from sunlight.”
[Pauly and Bompas] hope that the technique will be used in architectural design, to create windows that mould sunlight and throw images or patterns onto walls or floors,” which, if timed, milled, and manipulated just right, could produce a slowly animated sequence of images being projected by an otherwise empty window during different times of day.
Architectural Caustics
A Research PaperTo control the shape of a caustic pattern generated by a specular or refractive surface, we need to solve the inverse problem: how can we change the surface geometry, such that incident light is redirected to produce a desired caustic image?
Letters to the Future
The lapse of many years
At this point I wish to emphasize what I believe will ultimately prove to be the greatest purpose of our museum. This value will not, however, be realized until the lapse of many years, possibly a century, assuming that our material is safely preserved. And this is that the student of the future will have access to the original record of faunal conditions in California and the west, wherever we now work. He will know the proportional constituency of our faunae by species, the relative numbers of each species and the extent of the ranges of species as they exist today.
— Joseph Grinnell, 1910
The Grinnell System
The recording of field notes was common practice for biological surveyors and naturalists generations before Grinnell. His system continues this tradition but is distinguished by its distinctive standardized format. It consists of three sections:
- The journal contains a narrative account describing the study site and summarizing each day’s activities and observations, including a list of species encountered. This section is often peppered with sketches, photographs, or maps.
- The catalog is a sequential record of all voucher specimens collected, each with a unique field number and the information needed for the specimen’s museum tag, such as its sex, mass, breeding status, and standard body measurements.
- Species accounts are species-specific summaries of information and observations, gradually accumulated over multiple days at a site or across multiple sites, that eventually grow to detailed summaries of physical description, seasonal behaviors, microhabitat associations, and other characteristics.
Separating the notebook in this fashion allows each section to have its own context-specific structure and format.
Jim's system
From the earliest days of my fieldwork until now, throughout a given day I jotted notes, typically in pencil, into a small, spiral-bound pocket notebook, remembering the admonition not to trust one’s memory but to record observations as continually as possible. I then transcribes these notes into my handwritten journal in the evenings on the best of days or every few days when an intense field effort allowed.
From 2000 onward, I would still takes pencil notes in a small pocket notebook in the field, but I transcribes these into a word-processor document with margins set for the size of our field note pages. I combined this document with my field catalog for a particular trip and eventually both would be bound in the same manner as standard, handwritten field notes.
This approach had the advantage of producing both an archival paper copy as well as an electronic copy. It was also easy to intersperse specialized maps and digital photographs, which had become the norm by this time, throughout the journal text.
John's system
I have two field notebooks: a “raw" notebook and my formal Grinnellian notebook.
In the field, I take all my raw notes in a waterproof notebook using a fine-point permanent pen (or pencil when its raining). The entries have virtually no structure other than the date at the top of (almost) every page.
At the end of the day, I transcribe the notes into my Grinnellian journal as if I were writing a latter to a colleague.
Record them all
You can’t tell often in advance which observations will prove valuable. Do record them all!
— Joseph Grinnell, 1908
Recommendations for field notes
Being an end-user of someone else’s field notes certainly gives you insight into the benefits of good note-taking skills. Our experiences as end-users and creators of archival field notes lead us to a few specific recommendations:
(1) Don’t get bogged down in the details of format or style.
Rules are counterproductive if they prevent a researcher from taking field notes in the first place.
You will get more return by focusing on your content than by refining your formatting.
(2) Compose your notes as if you were writing a letter to someone a century in the future.
Writing for an external audience requires you to be more explicit in your descriptions and to take less knowledge for granted. Avoid the use of abbreviations, symbols, and other shortcuts that only you will understand.
Ask yourself: How would you describe this to someone over the phone?
(3) It is better to spend five minutes writing the important details than twenty minutes writing the trivial ones.
Field notes
Field notes example.
Camp's notes
Grinnell-era field notes example, Charles L. Camp.