astronomy

Wilhelm Pfeffer

Wilhelm Pfeffer is a astronomy 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 Wilhelm Pfeffer rather than just read about it. In short: Wilhelm Friedrich Philipp Pfeffer (9 March 1845 – 31 January 1920) was a German botanist and plant physiologist born in Grebenstein. Academic career He studied chemistry and pharmacy at the University of Göttingen, where his instructors included Friedrich Wöhler (1800-1882), William Eduard Weber (1804-1891) and Wilhelm Rudolph Fittig (1835-1910).

Key takeaways

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

Reference excerpt

Wilhelm Friedrich Philipp Pfeffer (9 March 1845 – 31 January 1920) was a German botanist and plant physiologist born in Grebenstein.

Academic career He studied chemistry and pharmacy at the University of Göttingen, where his instructors included Friedrich Wöhler (1800-1882), William Eduard Weber (1804-1891) and Wilhelm Rudolph Fittig (1835-1910). Afterwards, he furthered his education at the universities of Marburg and Berlin. At Berlin, he studied under Alexander Braun (1805-1877) and was an assistant to Nathanael Pringsheim (1823-1894). Later on, he served as an assistant to Julius von Sachs (1832-1897) at Würzburg, In 1873 he was appointed professor of pharmacology and botany at the University of Bonn, followed by professorships at the Universities of Basel (from 1877) and Tübingen (from 1878), where he also served as director of the Botanischer Garten der Universität Tübingen. In 1887 he became a professor at the University of Leipzig and director of its botanical garden. He was elected to honorary membership of the Manchester Literary and Philosophical Society, in 1894, to membership of the Royal Swedish Academy of Sciences and an International Honorary Member of the American Academy of Arts and Sciences in 1897, an International Member of the United States National Academy of Sciences in 1903, and the American Philosophical Society in 1909.

Scientific work Pfeffer was a pioneer of modern plant physiology. His scientific interests included the thermonastic and photonastic movements of flowers, the nyctinastic movements of leaves, protoplastic physics and photosynthesis. In 1877, while researching plant metabolism, Pfeffer developed a semi-porous membrane to study the phenomena of osmosis. The eponymous Pfeffer cell is named for the osmometric device he constructed for determining the osmotic pressure of a solution. During his tenure at Leipzig, Pfeffer published an article on the use of photography to study plant growth. He wanted to extend the chronophotographic experiments of Étienne-Jules Marey (1830-1904) by producing a short film involving the stages of plant growth. This "movie" would be filmed over a period of weeks by frame-at-a-time exposure taken at regular spaced intervals. Later, time-lapse photography would become a commonplace procedure.

Written works Physiologische Untersuchungen - 1873 (Physiological studies) Lehrbuch der Pflanzenphysiologie (Textbook of plant physiology). Die periodischen Bewegungen der Blattorgane - 1875 (The periodic movements of "leaf organs") Osmotische Untersuchungen – Studien zur Zellmechanik - 1877 (Osmotic studies) Beiträge zur Kenntniss der Oxydationsvorgänge in lebenden Zellen - 1889 (Contributions to the knowledge of the oxidative processes in living cells). Über Aufnahme und Ausgabe ungelöster Körper - 1890 Studien zur Energetik der Pflanze - 1892 (Studies on the energetics of plants) Druck- und Arbeitsleistung durch wachsende Pflanzen - 1893 Untersuchungen über die Entstehung der Schlafbewegungen der Blattorgane - 1907 Der Einfluss von mechanischer Hemmung und von Belastung auf die Schlafbewegung - 1911 (The influence of mechanical stress on the inhibition of sleep and movement). Beiträge zur Kenntniss der Entstehung der Schlafbewegungen- 1915 (Contributions to the knowledge on the genesis of sleep movements).

References List of publications copied from an equivalent article at the German Wikipedia.

Illustrations

Worked examples

Example 1 — a first encounter with Wilhelm Pfeffer

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

In research: Wilhelm Pfeffer appears in astronomy 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 Wilhelm Pfeffer 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: Wilhelm Pfeffer is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1845 births, 1920 deaths, 19th-century German botanists, so understanding it makes those chapters shorter.
In everyday life: Look for Wilhelm Pfeffer 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 Wilhelm Pfeffer in 20 minutes

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

Frequently asked questions

What is Wilhelm Pfeffer in simple terms?

Wilhelm Friedrich Philipp Pfeffer (9 March 1845 – 31 January 1920) was a German botanist and plant physiologist born in Grebenstein. Academic career He studied chemistry and pharmacy at the University of Göttingen, where his instructors included Friedrich Wöhler (1800-1882), William Eduard Weber (1…

Why does Wilhelm Pfeffer matter?

Because it connects several astronomy 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 Wilhelm Pfeffer?

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 Wilhelm Pfeffer.