physics

Lucien LaCoste

Lucien LaCoste is a physics 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 Lucien LaCoste rather than just read about it. In short: Lucien LaCoste (1908 – 1995) was a physicist and metrologist. He coinvented the modern gravimeter and invented the zero-length spring and vehicle-mounted gravimeters.

Key takeaways

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

Reference excerpt

Lucien LaCoste (1908 – 1995) was a physicist and metrologist. He coinvented the modern gravimeter and invented the zero-length spring and vehicle-mounted gravimeters. He was also co-founder of LaCoste Romberg, a prominent company selling gravimetric instruments.

Life

LaCoste discovered the zero-length spring in 1932 while performing an assignment in Arnold Romberg's undergraduate physics course. A zero-length spring is a spring supported in such a way that its exerted force is proportional to its length, rather than the distance it is compressed. That is, over at least part of its travel, it does not conform to Hooke's law of spring compression. The zero-length spring is extremely important to seismometers and gravimeters because it permits the design of vertical pendulums with (theoretically) infinite periods. In practice, periods of a thousand seconds are possible, a hundredfold increase from other forms of pendulum. Over a short period starting in 1932, the design of these instruments was revolutionized, obsoleting all previous designs. During this period, LaCoste and his physics teacher Arnold Romberg invented the first modern seismographs and gravimeters, using steel and quartz (respectively) zero-length springs. While a graduate student, LaCoste decided to go into business together with Romberg, selling advanced gravimeters to oil-exploration companies. LaCoste's most famous invention is the ship- and aircraft-mounted gravimeter. These revolutionized exploration for minerals by allowing wide-ranging geological surveys. The chief problem that Lacoste defeated was to distinguish the accelerations of the vehicles from the accelerations due to gravity, and measure the minute changes in gravity. Since the accelerations from the vehicle typically are hundreds to thousands of times more forceful than the measured changes, this invention was considered impossible until LaCoste demonstrated it.

References

December 1984 issue of The Leading Edge. Eos, December 12, 1995, p. 516.

External links AGU's LaCoste page at the Wayback Machine (archived May 27, 2008)

Worked examples

Example 1 — a first encounter with Lucien LaCoste

Start with the simplest possible case. Write down what Lucien LaCoste claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In physics, 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 Lucien LaCoste 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 Lucien LaCoste 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 Lucien LaCoste

In research: Lucien LaCoste appears in physics 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 Lucien LaCoste 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: Lucien LaCoste is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1908 births, 1995 deaths, 20th-century American physicists, so understanding it makes those chapters shorter.
In everyday life: Look for Lucien LaCoste 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 Lucien LaCoste in 20 minutes

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

Frequently asked questions

What is Lucien LaCoste in simple terms?

Lucien LaCoste (1908 – 1995) was a physicist and metrologist. He coinvented the modern gravimeter and invented the zero-length spring and vehicle-mounted gravimeters.

Why does Lucien LaCoste matter?

Because it connects several physics 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 Lucien LaCoste?

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 Lucien LaCoste.