science

Grain

Grain 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 Grain rather than just read about it. In short: A grain is a small, hard, dry fruit (caryopsis)–with or without an attached hull layer–harvested for human or animal consumption. A grain crop is a grain-producing plant.

Key takeaways

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

Reference excerpt

A grain is a small, hard, dry fruit (caryopsis)–with or without an attached hull layer–harvested for human or animal consumption. A grain crop is a grain-producing plant. The two main types of commercial grain crops are cereals and legumes. After being harvested, dry grains are more durable than other staple foods, such as starchy fruits (plantains, breadfruit, etc.) and tubers (sweet potatoes, cassava, and more).This durability has made grains well suited to industrial agriculture, since they can be mechanically harvested, transported by rail or ship, stored for long periods in silos, and milled for flour or pressed for oil. The grain market is a major global agricultural market that includes crops such as maize, rice, soybeans, wheat, and other grains.

Cereal and non-cereal grains In the grass family, a grain (narrowly defined) is a caryopsis, a fruit with its wall fused on to the single seed inside, belonging to a cereal such as wheat, maize, or rice. More broadly, in agronomy and commerce, seeds or fruits from other plant families are called grains if they resemble cereal caryopses. For example, amaranth is sold as "grain amaranth", and amaranth products may be described as "whole grains". The pre-Columbian civilizations of the Andes had grain-based food systems, but at higher elevations none of the grains belonged the cereal family. All three grains native to the Andes (kaniwa, kiwicha, and quinoa) are broad-leaved plants rather than grasses.

Cereal grains

Many different species of cereal are cultivated for their grains.

Warm-season cereals fonio maize (corn) millets (of multiple species) sorghum

Cool-season cereals barley oats rice rye spelt teff triticale wheat wild rice

Pseudocereal grains

Starchy grains from broadleaf (dicot) plant families are cultivated as nutritious alternatives to cereals. The three major pseudocereal grains are:

amaranth (Amaranth family) also called kiwicha buckwheat (Smartweed family) quinoa (Amaranth family, formerly classified as Goosefoot family)

Pulses or grain legumes

Pulses (the dried seeds of legumes, members of the pea family), have a higher protein content than most other plant foods, at around 20%, while soybeans have as much as 35%. As is the case with all other whole plant foods, pulses also contain carbohydrates and fat. Common pulses include:

chickpeas common beans common peas (garden peas) fava beans lentils lima beans lupins green gram black gram peanuts pigeon peas runner beans soybeans

Oilseed grains Oilseed grains are grown primarily for the extraction of their edible oil. Vegetable oils provide dietary energy and some essential fatty acids. They are also used as fuel and lubricants.

Mustard family

black mustard India mustard rapeseed (including canola)

Aster family

safflower sunflower seed

Other families flax seed (Flax family) hemp seed (Hemp family) poppy seed (Poppy family)

Historical importance Because grains are small, hard and dry, they can be stored, measured, and transported more readily than can other kinds of food crops such as fresh fruits, roots and tubers. The development of grain agriculture allowed excess food to be produced and stored easily which could have led to the creation of the first temporary settlements and the division of society into classes. This assumption that grain agriculture led to early settlements and social stratification has been challenged by James C. Scott in his book Against the Grain. He argues that the transition from hunter-gatherer societies to settled agrarian communities was not a voluntary choice driven by the benefits of increased food production due to the long storage potential of grains, but rather that the shift towards settlements was a coerced transformation imposed by dominant members of a society seeking to expand control over labor and resources.

Trade

Occupational safety and health Those who handle grain at grain facilities may encounter numerous occupational hazards and exposures. Risks include grain entrapment, where workers are submerged in the grain and unable to extricate themselves and dust explosions caused by fine particles of grain dust.

Illustrations

Worked examples

Example 1 — a first encounter with Grain

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

In research: Grain 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 Grain 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: Grain is common in secondary-school and first-year university syllabi. It links to neighbouring topics Crops, Edible nuts and seeds, Food ingredients, so understanding it makes those chapters shorter.
In everyday life: Look for Grain 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 Grain in 20 minutes

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

Frequently asked questions

What is Grain in simple terms?

A grain is a small, hard, dry fruit (caryopsis)–with or without an attached hull layer–harvested for human or animal consumption. A grain crop is a grain-producing plant.

Why does Grain 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 Grain?

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 Grain.