science

Second principal meridian

Second principal meridian 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 Second principal meridian rather than just read about it. In short: The second principal meridian, or Paoli Meridian, coincides with 86° 28′ of longitude west from Greenwich, starts from a point two and one half miles west of the confluence of the Little Blue and Ohio rivers, runs north to the northern boundary of Indiana, and, with the base line in latitude 38° 28′ 20″, governs the surveys in Indiana and part of those in Illinois. See also List of principal and guide meridians and…

Key takeaways

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

Reference excerpt

The second principal meridian, or Paoli Meridian, coincides with 86° 28′ of longitude west from Greenwich, starts from a point two and one half miles west of the confluence of the Little Blue and Ohio rivers, runs north to the northern boundary of Indiana, and, with the base line in latitude 38° 28′ 20″, governs the surveys in Indiana and part of those in Illinois.

See also List of principal and guide meridians and base lines of the United States

Sources Raymond, William Galt (1914). Plane Surveying for Use in the Classroom and Field (via Internet Archive). New York: American Book Company. "Chapter Five: Land Surveying". Survey Manual (PDF). Springfield, Illinois: Illinois Department of Transportation, Bureau of Design and Environment. 2003-02-28. p. 5. Archived from the original (PDF) on 2011-05-25. Retrieved 2008-10-30.

External links "Cadastral Survey [second principal meridian]". U.S. Bureau of Land Management. Archived from the original on 2013-02-22. Retrieved 2012-09-29. "Principal Meridians and Base Lines". U.S. Bureau of Land Management. Archived from the original on 2012-10-18. Retrieved 2012-09-29. "The Second Principal Meridian, Paoli, Indiana". Principal Meridian Project. Retrieved 2012-09-29. "Second Principal Meridian". The Center for Land Use Interpretation. Retrieved 2012-09-29. "Hoosier National Forest, Initial Point". U.S. Forest Service. Retrieved 2012-10-07.

Illustrations

Worked examples

Example 1 — a first encounter with Second principal meridian

Start with the simplest possible case. Write down what Second principal meridian 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 Second principal meridian 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 Second principal meridian 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 Second principal meridian

In research: Second principal meridian 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 Second principal meridian 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: Second principal meridian is common in secondary-school and first-year university syllabi. It links to neighbouring topics Meridians (geography), Meridians and base lines of the United States, so understanding it makes those chapters shorter.
In everyday life: Look for Second principal meridian 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 Second principal meridian in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Second principal meridian 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 Second principal meridian out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Second principal meridian in simple terms?

Why does Second principal meridian 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 Second principal meridian?

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 Second principal meridian.