earth science

Perboewatan

Perboewatan 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 Perboewatan rather than just read about it. In short: Perboewatan (also spelled Perbuatan or Perbuwatan; apparently a Malay word of uncertain derivation) was one of the three main volcanic cones (the others being Danan and Rakata) on the island of Krakatoa (or Krakatau), in the Sunda Strait, in Indonesia. It was the lowest (121 m) and northernmost of the cones.

Key takeaways

Perboewatan 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 Perboewatan to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Perboewatan from memory before moving on to harder problems.

Reference excerpt

Perboewatan (also spelled Perbuatan or Perbuwatan; apparently a Malay word of uncertain derivation) was one of the three main volcanic cones (the others being Danan and Rakata) on the island of Krakatoa (or Krakatau), in the Sunda Strait, in Indonesia. It was the lowest (121 m) and northernmost of the cones. Perboewatan was completely destroyed during the 1883 eruption; the caldera is approximately 250 metres (820 ft) deep at its former location. Photographed on May 27, 1883 by visitors to the island, Perboewatan is the only cone on Krakatoa of which quality pre-1883 photographs exist. In the photos, it appears to be a low hill with a flat top. Climbers reported the erupting crater to be about 1,005 m (3,297 ft) across at the top, narrowing to 46 m (151 ft) at the bottom and 150–240 m deep. Samples were collected, revealing upon analysis a silica (SiO2) content of 65%. In February 1681, two individuals traveling through the Straits witnessed the eruption of Krakatoa. Johann Wilhelm Vogel, a mining assayer, was told that the eruption began in May 1680. Since they were passing to the north of the island, it was apparent that the cone they witnessed was Perboewatan. This is backed up by Verbeek's visit in 1880, during which he took samples from a "fresh-looking" lava flow on the northern coast. The flow was unweathered, with little vegetation, indicating recent origin. Perboewatan began erupting on 20 May 1883, having previously been thought extinct. On 27 May 1883, the General Governor Loudon took a sight-seeing group of about 90 to Krakatoa, landing on the northern end of the island, just below Perboewatan. Several in the party climbed up to the crater, which was still erupting. As the ship was leaving, a photographer took several photos of the erupting volcano. In Rogier Verbeek's reconstruction of the eruption, Perboewatan is thought to have been the first cone destroyed, at about 4:40 am on 27 August.

References

Furneaux, Rupert (1964). Krakatoa. Englewood Cliffs, N.J., Prentice-Hall.

Worked examples

Example 1 — a first encounter with Perboewatan

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

In research: Perboewatan 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 Perboewatan 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: Perboewatan is common in secondary-school and first-year university syllabi. It links to neighbouring topics Krakatoa, Sumatra geography stubs, Sunda Strait, so understanding it makes those chapters shorter.
In everyday life: Look for Perboewatan 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 Perboewatan in 20 minutes

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

Frequently asked questions

What is Perboewatan in simple terms?

Why does Perboewatan 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 Perboewatan?

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 Perboewatan.