science

Porhalaan

Porhalaan is a 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 Porhalaan rather than just read about it. In short: The Porhalaan is the traditional calendar of the Batak people of North Sumatra, Indonesia. The Batak Calendar is a lunisolar calendar consisting of 12 months divided to 30 days with an occasional leap month.

Key takeaways

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

Reference excerpt

The Porhalaan is the traditional calendar of the Batak people of North Sumatra, Indonesia. The Batak Calendar is a lunisolar calendar consisting of 12 months divided to 30 days with an occasional leap month. The Batak calendar is derived from Hindu calendar. The Batak people do not use the porhalaan as a mean to tell time, but rather to determine auspicious day, which is only used by the Batak shaman.

Ritual The name porhalaan came from the word hala, which is derived from Sanskrit kala, "scorpion", as the practice put observation of constellations into account. The porhalaan is used by the Batak people for divination. Batak people did not use the porhalaan for telling time. The responsibility of interpreting the porhalaan fell solely to the chief male ritualist known as the datu. The datu would read the porhalaan to determine which day is considered auspicious or inauspicious to hold a certain ritual. In order to minimize the risk of accidentally selecting an unfavorable day due to errors in calendar management, days are often chosen based on whether the day is able to promise happiness in two months time, probably the current month and the following one. There is often an extra 13th month in the calendar that serves this purpose, originally a Hindu leap year, but in the Batak context, it is used for a different reason. If the additional 13th month is not available, then the first month is simply used again for protection. Whether the 13th month is used to compensate for the difference to the solar year is not proven in the context of Batak society. The Porhalaan is usually written as a table of square boxes of 30 columns (days) of 12 or 13 rows (months) as recorded in the pustaha, the Batak magic book. Sometimes the porhalaan is written on a cylindrical piece of bamboo. The Porhalaan is the clearest example of the Batakization of Hindu culture. The original Hindu Calendar was borrowed, modified and reworked according to Batak empirical and pragmatic principles. The result is a simplification of the original calendar. All that remains of a complicated system of adjusting lunar months to the solar Zodiac is a divination calendar which is not used for the purpose of telling times.

Calendar system There is no designation of year in Batak Calendar. New Year begins on the New Moon in May, when the constellation Orion (siala sungsang) vanishes in the west and the constellation Scorpius (siala poriama) rises in the east. Porhalaan is divided into 12 months, each contains 30 days. Each month was named by its number, the first month is called simply "first month" or bulan si pahasada, second month is bulan si pahadua, etc. The eleventh month is called bulan li, while the twelfth month is named bulan hurung. The first day of each month (bona ni bulan) fell directly one day after the New Moon. The Full Moon usually fell on the 14th or 15th day. Porhalaan do not use the term for "week", but each month is divided into four each containing seven days. The name of each of the seven days was borrowed from the Sanskrit name. The first day is called Aditya ("sun"), the second Soma ("moon"), Anggara (Mars), Budha (Mercury), Brihaspati (Jupiter), Syukra (Venus), and Syanaiscara (Saturn). In the porhalaan way of naming days, the name of the day in the context of '30 days of a month' is maintained. For example, the third day in a month which fell on Tuesday is known Nggara telu uari. sixth day is Cukera enem berngi, ninth is Suma na siwah, tenth is Nggara sepuluh, and so on. The 7th, 14th, 21st, and 28th day is named after the moon phase, that is bělah (first quarter waxing moon), bělah purnama (full moon), bělah turun (third quarter waning moon), dan mate bulan (dead moon). The word pultak ("increasing") is added to the bright fortnight days of the porhalaan when the moon phase grows, while the word cěpik ("decreasing") is added to the dark fortnight days of the porhalaan when the moon phase decreases; this is obviously influenced by the Hindu shukla pasha and krishna paksha.

Worked examples

Example 1 — a first encounter with Porhalaan

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

In research: Porhalaan appears in 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 Porhalaan 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: Porhalaan is common in secondary-school and first-year university syllabi. It links to neighbouring topics Batak, Calendars, so understanding it makes those chapters shorter.
In everyday life: Look for Porhalaan 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 Porhalaan in 20 minutes

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

Frequently asked questions

What is Porhalaan in simple terms?

Why does Porhalaan matter?

Because it connects several 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 Porhalaan?

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 Porhalaan.