science

Osborne Fire Finder

Osborne Fire Finder is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Osborne Fire Finder rather than just read about it. In short: The Osborne Fire Finder is a type of alidade used by fire lookouts to find a directional bearing (azimuth) to smoke in order to alert fire crews to a wildland fire. History and development The forerunner to the device was invented around 1840 by Sir Francis Ronalds to help combat fire in London – he also named his innovation the "Fire Finder".

Key takeaways

Osborne Fire Finder belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Osborne Fire Finder to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Osborne Fire Finder from memory before moving on to harder problems.

Reference excerpt

The Osborne Fire Finder is a type of alidade used by fire lookouts to find a directional bearing (azimuth) to smoke in order to alert fire crews to a wildland fire.

History and development The forerunner to the device was invented around 1840 by Sir Francis Ronalds to help combat fire in London – he also named his innovation the "Fire Finder". Ronalds's fire finder comprised a theodolite atop a watchtower. Bearings and vertical angles from the horizon to surrounding features were recorded either on a surrounding cylinder in the form of a panorama or on a circular table at the base of the instrument. The location of any fire could thus be pinpointed even in the dark. The modern version was created by William "W. B." Osborne, a United States Forest Service employee from Portland, Oregon, and has been in service since 1915. Mr. Osborne also designed the photo-recording transit for making panoramic records of forest conditions, as well as a collapsible water-bag knapsack for firefighting (patented in the US in 1935). Many fire finders were manufactured from 1920 through 1935, but the manufacturer, Leupold & Stevens, Inc., stopped production of replacement parts after 1975.

Use The system is composed of a topographic map of the area oriented and centered on a horizontal plane table with a circular rim graduated in degrees (and fractions). Two sighting apertures are mounted above the map on opposite sides of the ring and slide around the arc.

The device is used by moving the sights until the observer can peek through the nearer sighting hole and view the cross hairs in the further sight aligned with the fire. The fire lookout notes the degrees on the graduated ring beneath the sight. Early Fire Finders were capable of a crude estimate of elevation based upon the level and elevation of the table, calculating distance and rough position of the fire by reference to any distinctive terrain features and by use of the scale shown on the map. However, in actual practice, fire distance and location were normally established using two or more Fire Finder-equipped lookout towers, using the intersection method to fix the precise location of the fire. Dispatchers at a central facility used a compass rose to mark lines of position from each reporting tower onto a large map to quickly find where the reported bearings intersect. Today, a more precise determination of a fire location can be made by the use of a single Fire Finder in conjunction with a digital elevation model (DEM).

Notes

References William B. Osborne profile Archived 2009-12-08 at the Wayback Machine, USFS History section, Forest History Society website Mooers Jr., Robert L., Finding Your Way In The Outdoors, Outdoor Life Press (1972), ISBN 0-943822-41-6 Fire Management Tech Tips USDA Forest Service, October 2003 Document: 0351 1311=SDTDC

External links

History of the Osborne Fire Finder by Ray Kresek

Illustrations

Worked examples

Example 1 — a first encounter with Osborne Fire Finder

Start with the simplest possible case. Write down what Osborne Fire Finder claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Osborne Fire Finder before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Osborne Fire Finder ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Osborne Fire Finder

In research: Osborne Fire Finder appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Osborne Fire Finder in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Osborne Fire Finder is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1915 introductions, Surveying instruments, Wildfire suppression equipment, so understanding it makes those chapters shorter.
In everyday life: Look for Osborne Fire Finder outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Osborne Fire Finder in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Osborne Fire Finder means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Osborne Fire Finder out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Osborne Fire Finder in simple terms?

The Osborne Fire Finder is a type of alidade used by fire lookouts to find a directional bearing (azimuth) to smoke in order to alert fire crews to a wildland fire. History and development The forerunner to the device was invented around 1840 by Sir Francis Ronalds to help combat fire in London – h…

Why does Osborne Fire Finder matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Osborne Fire Finder?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Osborne Fire Finder.