earth science

Jakob Sederholm

Jakob Sederholm is a earth 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 Jakob Sederholm rather than just read about it. In short: Jakob Johannes Sederholm (20 July 1863 – 26 June 1934) was a Finnish petrologist most associated with his studies of migmatites. Troubled by illness throughout his life, Sederholm originally chose to study geology to allow him to work outdoors.

Key takeaways

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

Reference excerpt

Jakob Johannes Sederholm (20 July 1863 – 26 June 1934) was a Finnish petrologist most associated with his studies of migmatites. Troubled by illness throughout his life, Sederholm originally chose to study geology to allow him to work outdoors. After studying first in Helsinki (where he was a student of Fredrik Johan Wiik), then in Stockholm and Heidelberg, Sederholm returned to Finland to work for the Geological Survey of Finland. In 1893 he assumed the role of director of this institution, a post he occupied until his death forty years later. Working on local Precambrian basement rocks, Sederholm instigated a map-making programme that, between 1899 and 1925, published many maps and descriptions of their geological history. Gneisses in the areas he studied (the so-called Baltic Shield) were often of mixed composition, with layers of granitic rock being interleaved with metamorphic rock. Sederholm termed these as migmatites, and viewed them as the product of the intrusion of igneous magma into metamorphic rocks at depth. During his career Sederholm received both the Murchison Medal from the Geological Society of London (1928) and the Penrose Medal from the Geological Society of America (also 1928). The mineral sederholmite is named in his honour. Aside from his geological work, Sederholm was a member of the Diet of Finland, and undertook missions from this to the League of Nations. From 1921 to 1923, he led the League of Nations' "Commission of Enquiry in Albania" in the Principality of Albania. He was also a member and chairman (twice) of the Economic Society of Finland. In the 1974 historical novel Centennial, James Michener listed Sederholm among those scientists who made early estimates of the age of the Earth. Sederholm's estimate was 40 million years.

Papers Hackman V. Jacob Johannes Sederholm: Biographic notes and bibliography // Bulletin de la Commission géologique de Finlande. 1935. N 112. 34 p. Papunen H. Jakob Johannes Sederholm – geologi, humanisti ja totuudenetsijä // Geologi. 2009. N 2. P. 35-38.

References

External links Biographical entry (Encyclopædia Britannica) Sederholm, Johannes Jakob. Complete Dictionary of Scientific Biography, 2008. Jakob Johannes Sederholm - Lithos, 2010. Murchison Medal winners (Geological Society of London) Penrose Medal winners (Geological Society of America) Sederholmite mineral data (Mindat.org) Sederholmite mineral data (WebMineral.com)

Illustrations

Worked examples

Example 1 — a first encounter with Jakob Sederholm

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

In research: Jakob Sederholm appears in earth 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 Jakob Sederholm 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: Jakob Sederholm is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1863 births, 1934 deaths, Earth scientist stubs, so understanding it makes those chapters shorter.
In everyday life: Look for Jakob Sederholm 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 Jakob Sederholm in 20 minutes

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

Frequently asked questions

What is Jakob Sederholm in simple terms?

Why does Jakob Sederholm matter?

Because it connects several earth 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 Jakob Sederholm?

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 Jakob Sederholm.