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Palm (unit)

Palm (unit) 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 Palm (unit) rather than just read about it. In short: The palm is an obsolete anthropic unit of length, originally based on the width of the human palm and then variously standardized. The same name is also used for a second, rather larger unit based on the length of the human hand.

Palm (unit) — main illustration
Palm (unit) — illustration

Key takeaways

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

Reference excerpt

The palm is an obsolete anthropic unit of length, originally based on the width of the human palm and then variously standardized. The same name is also used for a second, rather larger unit based on the length of the human hand. The width of the palm was a traditional unit in Ancient Egypt, Israel, Greece, and Rome and in medieval England, where it was also known as the hand, handbreadth, or handsbreadth. The length of the hand—originally the Roman "greater palm"—formed the palm of medieval Italy and France. In Spanish customary units palmo menor or coto was the palm, while palmo was the span, the distance between an outstretched thumb and little finger. In Portuguese palmo or palmo de craveira was the span.

History

Ancient Egypt

The Ancient Egyptian palm (Ancient Egyptian: shesep) has been reconstructed as about 75 mm or 3 in. The unit is attested as early as the reign of Djer, third pharaoh of the First Dynasty, and appears on many surviving cubit-rods. The palm was subdivided into four digits (djeba) of about 19 mm (0.75 in). Three palms made up the span (pedj) or lesser span (pedj-sheser) of about 22.5 cm (9 in). Four palms made up the foot (djeser) of about 30 cm (1 ft). Five made up the remen of about 37.5 cm (1 ft 3 in). Six made up the "Greek cubit" (meh nedjes) of about 45 cm (1 ft 6 in). Seven made up the "royal cubit" (meh niswt) of about 52.5 cm (1 ft 9 in). Eight made up the pole (nbiw) of about 60 cm (2 ft).

Ancient Israel

The palm was not a major unit in ancient Mesopotamia but appeared in ancient Israel as the tefah, tepah, or topah (Hebrew: טפח, lit. "a spread"). Scholars were long uncertain as to whether this was reckoned using the Egyptian or Babylonian cubit, but now believe it to have approximated the Egyptian "Greek cubit", giving a value for the palm of about 74 mm or 2.9 in. As in Egypt, the palm was divided into four digits (etzba or etsba) of about 18.5 mm (0.73 in) and three palms made up a span (zeret) of about 22.1 cm (9 in). Six made up the Hebrew cubit (amah or ammah) of about 44.3 cm (1 ft 5 in), although the cubits mentioned in Ezekiel follow the royal cubit in consisting of seven palms comprising about 51.8 centimeters (1 ft 8 in).

Ancient Greece

The Ancient Greek palm (Ancient Greek: παλαιστή, palaistḗ, δῶρον, dō̂ron, or δακτυλοδόχμη, daktylodókhmē) made up ¼ of the Greek foot (poûs), which varied by region between 27–35 cm (11 in – 1 ft 2 in). This gives values for the palm between 6.7–8.8 cm (2.6–3.5 in), with the Attic palm around 7.4 cm (2.9 in). These various palms were divided into four digits (dáktylos) or two "middle phalanges" (kóndylos). Two palms made a half-foot (hēmipódion or dikhás); three, a span (spithamḗ); four, a foot (poûs); five, a short cubit (pygōn); and six, a cubit (pē̂khys). The Greeks also had a less common "greater palm" of five digits.

Ancient Rome

The Roman palm (Latin: palmus) or lesser palm (palmus minor) made up ¼ of the Roman foot (pes), which varied in practice between 29.2–29.7 cm (11.5–11.7 in) but is thought to have been officially 29.6 cm (11.7 in). This would have given the palm a notional value of 7.4 cm (2.9 in) within a range of a few millimeters. The palm was divided into four digits (digitus) of about 1.85 cm (0.7 in) or three inches (uncia) of about 2.47 cm (1.0 in). Three made a span (palmus maior or "greater palm") of about 22.2 cm (9 in); four, a Roman foot; five, a hand-and-a-foot (palmipes) of about 37 cm (1 ft 3 in); six, a cubit (cubitus) of about 44.4 cm (1 ft 5.5 in).

Continental Europe

The palms of medieval (Latin: palma) and early modern Europe—the Italian, Spanish, and Portuguese palmo and French palme—were based upon the Roman "greater palm", reckoned as a hand's span or length. In Italy, the palm (Italian: palmo) varied regionally. The Genovese palm was about 24.76–24.85 cm (9.7–9.8 in); in the Papal States, the Roman palm about 21.05 cm (8.3 in) according to Hutton but divided into the Roman "architect's palm" (palmo di architetti) of about 22.32 cm (8.8 in) and "merchant's palm" (palmo del braccio di mercantia) of about 21.21 cm (8.4 in) according to Greaves; and the Neapolitan palm reported as 20.31 cm (8.0 in) by Riccioli but 21.80 cm (8.6 in) by Hutton's other sources. On Sicily and Malta, it was 24.61 cm (9.7 in). In France, the palm (French: palme or pan) was about 24.61 cm (9.7 in) in Pernes-les-Fontaines, Vaucluse, and about 24.76 cm (9.7 in) in Languedoc. Palaiseau gave metric equivalents for the palme or palmo in 1816, and Rose provided English equivalents in 1900:

From 19th C. Italian sources emerges that : - the ancient Venetian palm, five of which made a passo (pace), was equivalent to 0.3774 metres. - the Neapolitan palm = 0.26333670 metres (from 1480 to 1840) - the Neapolitan palm = 0.26455026455 metres (according to the law of 6 April 1840) which differs from previously cited palm measure equivalents in metres above.

England

The English palm, handbreadth, or handsbreadth is three inches (7.62 cm) or, equivalently, four digits. The measurement was, however, not always well distinguished from the hand or handful, which became equal to four inches by a 1541 statute of Henry VIII. The palm was excluded from the British Weights and Measures Act 1824 that established the imperial system and is not a standard US customary unit.

Elsewhere The Moroccan palm is given by Hutton as about 18.20 cm (7.2 in).

Notes

References

Illustrations

Palm (unit): A diagram of various units derived from the human hand. The palm (3) was originally the width of the palm but was standardized as the somewhat smaller width of four digits (6). The related shaftment (1) and hand (2) were the width of the palm plus an open or closed thumb. The other units are the span (4) and finger (5).
A diagram of various units derived from the human hand. The palm (3) was originally the width of the palm but was standardized as the somewhat smaller width of four digits (6). The related shaftment (1) and hand (2) were the width of the palm plus an open or closed thumb. The other units are the span (4) and finger (5).
Palm (unit): Detail of the cubit rod in the Museo Egizio of Turin, showing digit, palm, hand and fist lengths
Detail of the cubit rod in the Museo Egizio of Turin, showing digit, palm, hand and fist lengths
Palm (unit): Sign giving the metric equivalents of the units in use in the 17th century in the covered market of Pernes-les-Fontaines in the Vaucluse
Sign giving the metric equivalents of the units in use in the 17th century in the covered market of Pernes-les-Fontaines in the Vaucluse
Palm (unit): The English palm as the width of four fingers.
The English palm as the width of four fingers.

Worked examples

Example 1 — a first encounter with Palm (unit)

Start with the simplest possible case. Write down what Palm (unit) 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 Palm (unit) 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 Palm (unit) 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 Palm (unit)

In research
Palm (unit) 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 Palm (unit) 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
Palm (unit) is common in secondary-school and first-year university syllabi. It links to neighbouring topics Human-based units of measurement, Obsolete units of measurement, Units of length, so understanding it makes those chapters shorter.
In everyday life
Look for Palm (unit) 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 Palm (unit) in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Palm (unit) means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Palm (unit) out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Palm (unit) in simple terms?

The palm is an obsolete anthropic unit of length, originally based on the width of the human palm and then variously standardized. The same name is also used for a second, rather larger unit based on the length of the human hand.

Why does Palm (unit) 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 Palm (unit)?

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 Palm (unit).

Tags

  • Human-based units of measurement
  • Obsolete units of measurement
  • Units of length

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