biology

Martin scale

Martin scale is a biology 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 Martin scale rather than just read about it. In short: The Martin scale is an older version of color scale commonly used in physical anthropology to establish more or less precisely the eye color of an individual. It was created by the anthropologist Rudolf Martin in the first half of the 20th century.

Key takeaways

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

Reference excerpt

The Martin scale is an older version of color scale commonly used in physical anthropology to establish more or less precisely the eye color of an individual. It was created by the anthropologist Rudolf Martin in the first half of the 20th century. Later he improved this scale with cooperation of Bruno K. Schultz, leading to the Martin-Schultz scale.

Original scale The original Martin scale, summarized below, consists of 16 colors (from light blue to dark brown-black) that correspond to the different eye colors observed in nature due to the amount of melanin in the iris. The numbering is reversed in order to match the Martin–Schultz scale, which is still used in biological anthropology. In this case, the higher the number, the lighter the eye color.

Light and light-mixed eyes (16-9) 16: light-blue iris 15-14-13: blue iris 12-11: light-gray iris 10-9: dark-gray iris

Mixed eyes (8-7) 8: green iris 7: green-brown iris

Dark-mixed eyes (6-5) 6: hazel iris 5: light-brown iris

Dark eyes (4-1) 4: brown iris 3-2: dark-brown iris 1: black-brown iris

Older versions Older versions of the Martin scale eye color chart have the following color divisions:

16-12: light and light-mixed iris 11-7: mixed iris 6-5: dark-mixed iris 4-1: dark iris

See also Eye color Martin–Schultz scale Human eye

Notes

Illustrations

Worked examples

Example 1 — a first encounter with Martin scale

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

In research: Martin scale appears in biology 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 Martin scale 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: Martin scale is common in secondary-school and first-year university syllabi. It links to neighbouring topics Biological anthropology, Color scales, Eye color, so understanding it makes those chapters shorter.
In everyday life: Look for Martin scale 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.

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Martin scale in 20 minutes

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

Frequently asked questions

What is Martin scale in simple terms?

Why does Martin scale matter?

Because it connects several biology 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 Martin scale?

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 Martin scale.