science

Phonomotor

Phonomotor 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 Phonomotor rather than just read about it. In short: The phonomotor or "vocal engine" was a device invented by Thomas Edison in 1878 to measure the mechanical force of sound. It converted sound energy or sound power into rotary motion which could drive a machine such as a small saw or drill.

Key takeaways

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

Reference excerpt

The phonomotor or "vocal engine" was a device invented by Thomas Edison in 1878 to measure the mechanical force of sound. It converted sound energy or sound power into rotary motion which could drive a machine such as a small saw or drill. It derived from his work on the telephone and phonograph.

Operation Sound waves entering a mouthpiece and falling on a diaphragm were conveyed by a piece of rubber tubing and a spring to a pawl, which vibrated against a very fine-toothed ratchet wheel. The diaphragm and mouthpiece were similar to those used on the phonograph. Vibrations caused by the voice caused a shaft and flywheel to rotate. Steady pressure from breath produced no motion, but some voices could produce rapid motion. The speed of rotation depended on the pitch of the sound. It was able to operate a small drill or saw which could bore or cut wood. When a long sustained sound got the flywheel up to an appreciable speed, considerable force was required to stop it.

Impact The Chicago Tribune in May 1878 predicted that it would be the basis for sound-powered toys such as dolls which bow when spoken to, though none are known to have been marketed. Edison described it as a scientific toy. A U.S patent application was filed for the "Vocal Engine" in 1878, and a patent was granted on December 10 of that year. An 1884 Nature article on sound mills, similar devices to the phonomotor, reported that Edison's device, "literally accomplished the feat of talking a hole through a deal board." A restored model of the phonomotor is in the Edison Menlo Park laboratory exhibit at the Greenfield Village Museum in Dearborn, Michigan, and was exhibited in operation for visitors in the 1930s.

References

External links T.A. Edison, "Vocal Engine" Archived September 22, 2016, at the Wayback Machine. US Patent 210,767, Patented December 10, 1878.

Illustrations

Worked examples

Example 1 — a first encounter with Phonomotor

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

In research: Phonomotor 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 Phonomotor 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: Phonomotor is common in secondary-school and first-year university syllabi. It links to neighbouring topics 19th-century inventions, American inventions, Audiovisual introductions in 1878, so understanding it makes those chapters shorter.
In everyday life: Look for Phonomotor 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 Phonomotor in 20 minutes

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

Frequently asked questions

What is Phonomotor in simple terms?

Why does Phonomotor 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 Phonomotor?

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 Phonomotor.