astronomy

Johannes Phocylides Holwarda

Johannes Phocylides Holwarda 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 Johannes Phocylides Holwarda rather than just read about it. In short: Johannes Phocylides Holwarda (Jan Fokkesz, Jan Fokker, Johann Holwarda, Johannes Fokkes Holwarda, Jan Fokkens Holwarda, Jan Fokkes van haylen) (February 19, 1618—January 22, 1651) was a Frisian astronomer, physician, and philosopher. He was a professor of philosophy at the University of Franeker from 1639 to 1651.

Key takeaways

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

Reference excerpt

Johannes Phocylides Holwarda (Jan Fokkesz, Jan Fokker, Johann Holwarda, Johannes Fokkes Holwarda, Jan Fokkens Holwarda, Jan Fokkes van haylen) (February 19, 1618—January 22, 1651) was a Frisian astronomer, physician, and philosopher. He was a professor of philosophy at the University of Franeker from 1639 to 1651. Born in Holwerd, he is best remembered for his discovery of the length of Mira's (Omicron Ceti's) varying appearance cycle. In a systematic study in 1638, he found that Mira disappeared and reappeared in a varying cycle of about 330 days. Holwarda was also a supporter of "atomism". His Philosophia Naturalis, seu Physica Vetus-Nova, published posthumously in 1651, defines matter and form: matter is extended and divided into atoms while form is the texture of atoms. According to Phocylides, bodies are formed from atoms and a lack of atoms. Atoms, which he distinguished as simple or compound, are solid corpuscles that receive motion directly from God. The lunar crater Phocylides is named after him.

Notes

Illustrations

Worked examples

Example 1 — a first encounter with Johannes Phocylides Holwarda

Start with the simplest possible case. Write down what Johannes Phocylides Holwarda 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 Johannes Phocylides Holwarda 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 Johannes Phocylides Holwarda 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 Johannes Phocylides Holwarda

In research: Johannes Phocylides Holwarda 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 Johannes Phocylides Holwarda 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: Johannes Phocylides Holwarda is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1618 births, 1651 deaths, 17th-century Dutch astronomers, so understanding it makes those chapters shorter.
In everyday life: Look for Johannes Phocylides Holwarda 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 Johannes Phocylides Holwarda in 20 minutes

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

Frequently asked questions

What is Johannes Phocylides Holwarda in simple terms?

Why does Johannes Phocylides Holwarda 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 Johannes Phocylides Holwarda?

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 Johannes Phocylides Holwarda.