science

Opisometer

Opisometer 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 Opisometer rather than just read about it. In short: An opisometer, also called a curvimeter, meilograph, or map measurer, is an instrument for measuring the lengths of arbitrary curved lines. Explanation A simple opisometer consists of a toothed wheel of known circumference on a handle.

Key takeaways

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

Reference excerpt

An opisometer, also called a curvimeter, meilograph, or map measurer, is an instrument for measuring the lengths of arbitrary curved lines.

Explanation A simple opisometer consists of a toothed wheel of known circumference on a handle. The wheel is placed in contact with the curved line to be measured and run along its length. By counting the number of teeth passing a mark on the handle while this is done, the length of the line can be ascertained:

line length = wheel circumference × teeth counted/teeth on wheel. In more sophisticated models, sometimes called a chartometer, the wheel is connected via gearing to a rotary dial from which the line length can be directly read. The instrument is most commonly used to measure the lengths of roads, rivers and other line features on maps. Opisometers designed for this purpose provide scales reading the measured distance in kilometers and miles.

History of the opisometer Early versions of this instrument were patented in 1873 by the English engineer Edward Russell Morris. The instruments he produced were initially described as a Patent Chartometer although later versions were sold under the curious name of Wealemefna. Writing in 1881, Morris described how he had created a wholly original name in an attempt to outwit his imitators; he also refused to disclose the origin of the word.

See also Planimeter Steinhaus longimeter Surveyor's wheel

References

Media related to Opisometers at Wikimedia Commons The dictionary definition of opisometer at Wiktionary

Illustrations

Worked examples

Example 1 — a first encounter with Opisometer

Start with the simplest possible case. Write down what Opisometer 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 Opisometer 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 Opisometer 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 Opisometer

In research: Opisometer 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 Opisometer 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: Opisometer is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cartography, Length, distance, or range measuring devices, Navigational equipment, so understanding it makes those chapters shorter.
In everyday life: Look for Opisometer 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 Opisometer in 20 minutes

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

Frequently asked questions

What is Opisometer in simple terms?

An opisometer, also called a curvimeter, meilograph, or map measurer, is an instrument for measuring the lengths of arbitrary curved lines. Explanation A simple opisometer consists of a toothed wheel of known circumference on a handle.

Why does Opisometer 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 Opisometer?

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 Opisometer.